Internet-draft Media Server Markup Language February 2006
(MSML)
SIPPING A. Saleem
Internet Draft G. Sharratt
Expires: August 26, 2006 Convedia
February 26, 2006
Media Server Markup Language (MSML)
draft-saleem-msml-00
Status of this Memo
By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that other
groups may also distribute working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on August 26, 2006.
Copyright Notice
Copyright (C) The Internet Society (2006). All Rights Reserved.
Abstract
The Media Server Markup Language (MSML) is used to control and invoke
many different types of services on IP Media Servers. Clients can use
it to define how multimedia sessions interact on a Media Server and
to apply services to individuals or groups of users. MSML can be
Saleem & Sharratt Expires - August 2006 [Page 1]
Internet-draft Media Server Markup Language February 2006
(MSML)
used, for example, to control Media Server conferencing features such
as video layout and audio mixing, create sidebar conferences or
personal mixes, and set the properties of media streams. As well,
clients can use MSML to define media processing dialogs, which may be
used as parts of application interactions with users or conferences.
Transformation of media streams to and from users or conferences as
well as IVR dialogs are examples of such interactions, which are
specified using MSML. MSML clients may also invoke dialogs with
individual users or with groups of conference participants using
VoiceXML.
Table of Contents
1. Introduction...................................................5
2. Conventions used in this document..............................6
3. Glossary.......................................................6
4. MSML SIP Usage.................................................7
5. Language Structure.............................................9
5.1 Package Scheme.............................................9
5.2 Profile Scheme............................................12
6. Execution Flow................................................13
7. Media Server Object Model.....................................14
7.1 Objects...................................................15
7.2 Identifiers...............................................17
8. MSML Core Package.............................................19
8.1 <msml>....................................................20
8.2 <send>....................................................20
8.3 <result>..................................................21
8.4 <event>...................................................21
9. MSML Conference Core Package..................................22
9.1 Conferences...............................................22
9.2 Media Streams.............................................23
9.3 <createconference>........................................24
9.3.1 <reserve>............................................26
9.3.1.1 <resource>......................................26
9.4 <modifyconference>........................................27
9.5 <destroyconference>.......................................29
9.6 <audiomix>................................................29
9.6.1 <n-loudest>..........................................30
9.6.2 <asn>................................................30
9.7 <videolayout>.............................................31
9.7.1 <root>...............................................31
9.7.2 <region>.............................................32
9.7.3 <selector>...........................................35
9.7.3.1 <vas> Voice Activate Switching..................37
9.8 <join>....................................................38
Saleem & Sharratt Expires - August 2006 [Page 2]
Internet-draft Media Server Markup Language February 2006
(MSML)
9.9 <modifystream>............................................40
9.10 <unjoin>.................................................41
9.11 <monitor>................................................42
9.12 <stream>.................................................42
9.12.1 Audio Stream Properties.............................43
9.12.1.1 <gain>.........................................44
9.12.1.2 <clamp>........................................44
9.12.2 Video Stream Properties.............................44
9.12.2.1 <visual>.......................................45
10. MSML Dialog Packages.........................................45
10.1 Overview.................................................45
10.2 Primitives...............................................47
10.3 Events...................................................49
10.4 MSML Dialog Usage with SIP...............................50
10.5 MSML Dialog Structure and Modularity.....................52
10.6 MSML Dialog Core Package.................................52
10.6.1 <dialogstart>.......................................53
10.6.2 <dialogend>.........................................55
10.6.3 <send>..............................................56
10.6.4 <exit>..............................................57
10.6.5 <disconnect>........................................57
10.7 MSML Dialog Base Package.................................57
10.7.1 <play>..............................................58
10.7.1.1 <audio>........................................60
10.7.1.2 <video>........................................61
10.7.1.3 <media>........................................62
10.7.1.4 <var>..........................................62
10.7.1.5 <playexit>.....................................63
10.7.2 <dtmfgen>...........................................63
10.7.2.1 <dtmfgenexit>..................................64
10.7.3 <record>............................................64
10.7.3.1 <play>.........................................68
10.7.3.2 <recordexit>...................................68
10.7.4 <dtmf> or <collect>.................................68
10.7.4.1 <play>.........................................70
10.7.4.2 <pattern>......................................70
10.7.4.3 <detect>.......................................71
10.7.4.4 <noinput>......................................71
10.7.4.5 <nomatch>......................................71
10.7.4.6 <dtmfexit>.....................................72
10.7.5 <moml>..............................................72
10.8 MSML Dialog Group Package................................72
10.8.1 <group>.............................................76
10.8.2 <groupexit>.........................................76
10.9 MSML Dialog Transform Package............................76
10.9.1 <vad>...............................................77
10.9.1.1 <voice>, <silence>, <tvoice>, <tsilence>.......77
10.9.2 <gain>..............................................78
Saleem & Sharratt Expires - August 2006 [Page 3]
Internet-draft Media Server Markup Language February 2006
(MSML)
10.9.3 <agc>...............................................78
10.9.4 <gate>..............................................79
10.9.5 <clamp>.............................................79
10.9.6 <relay>.............................................79
10.10 MSML Dialog Speech Package..............................79
10.10.1 <speech>...........................................80
10.10.1.1 <grammar>.....................................81
10.10.1.2 <match>.......................................82
10.10.1.3 <noinput>.....................................82
10.10.1.4 <nomatch>.....................................82
10.10.1.5 <speechexit>..................................82
10.10.2 <play>.............................................83
10.10.2.1 <tts>.........................................83
10.11 MSML Dialog Fax Detection Package.......................83
10.11.1 <faxdetect>........................................83
10.12 MSML Dialog Fax Send/Receive Package....................84
10.12.1 <faxsend>..........................................84
10.12.1.1 <sendobj>.....................................86
10.12.1.2 <hdrfooter>...................................86
10.12.1.3 <rxpoll>......................................87
10.12.1.4 <faxstart>....................................87
10.12.1.5 <faxnegotiate>................................88
10.12.1.6 <faxpagedone>.................................88
10.12.1.7 <faxobjectdone>...............................88
10.12.1.8 <faxopcomplete>...............................88
10.12.1.9 <faxpollstarted>..............................89
10.12.2 <faxrcv>...........................................89
10.12.2.1 <rcvobj>......................................90
10.12.2.2 <txpoll>......................................91
11. Response Codes...............................................91
12. MSML Conference Examples.....................................93
12.1 Establishing a Dial-in Conference........................93
12.2 Example of a Sidebar Audio Conference....................97
12.3 Example of Removing a Conference.........................99
12.4 Example of Modifying Video Layout........................99
13. MSML Dialog Examples........................................100
13.1 Announcement............................................100
13.2 Voice Mail Retrieval....................................101
13.3 Play and Record.........................................102
13.4 Speech Recognition......................................103
13.5 Play and Collect........................................104
13.6 User Controlled Gain....................................106
14. Change Summary..............................................106
15. Future Work.................................................107
16. XML Schema - MSML Core and MSML Conference Core Packages....107
17. XML Schema – MSML Dialog/Transform/Speech/Fax Packages......118
18. Security Considerations.....................................138
19. IANA Considerations.........................................138
Saleem & Sharratt Expires - August 2006 [Page 4]
Internet-draft Media Server Markup Language February 2006
(MSML)
20. URN Sub-Namespace Registration..............................139
21. XML Schema Registration.....................................139
22. References..................................................139
Acknowledgments.................................................141
Authors' Addresses..............................................141
Intellectual Property Statement.................................142
Copyright Statement.............................................142
Disclaimer of Validity..........................................143
Acknowledgement.................................................143
1. Introduction
Media servers contain dynamic pools of media resources. Control
Agents and other users of media servers (called media server clients)
can define and create many different services based on how they
configure and use those resources. Often, that configuration and the
ways in which those resources interact will be changed dynamically
over the course of a call, to reflect changes in the way that an
application interacts with a user.
For example, a call may undergo an initial IVR dialog before being
placed into a conference. Calls may be moved from a main conference
to a sidebar conference and then back again. Individual calls may be
directly bridged to create small n-way calls or simple sidebars. None
of these change the SIP [1] dialog or RTP [15] session. Yet these do
affect the media flow and processing internal to the media server.
The Media Server Markup Language (MSML) is an XML [4] language used
to change the flow of and services on media streams within a media
server. It is used to invoke many different types of services on
individual sessions, groups of sessions, and conferences. MSML allows
the creation of conferences, bridging different sessions together,
and bridging sessions into conferences.
MSML may also be used to create user interaction dialogs and allows
the application of media transforms to media streams. Media
interaction dialogs created using MSML allow construction of IVR
dialog sessions to individual users as well as to groups of users
participating in a conference. Dialogs may also be specified using
other languages, VoiceXML [7], which support complete single-party
application logic to be executed on the Media Server.
MSML is a transport independent language, such that it does not rely
on underlying transport mechanisms and language semantics are
independent of transport. However, SIP is a typical and commonly used
transport mechanism for MSML, invoked using the SIP URI scheme. This
Saleem & Sharratt Expires - August 2006 [Page 5]
Internet-draft Media Server Markup Language February 2006
(MSML)
specification defines using MSML Dialogs using SIP as the transport
mechanism.
A network connection may be established with the media server using
SIP. Media received and transmitted on that connection will flow
through different media resources on the media server depending on
the requested service. Basic Network Media Services with SIP [9]
defines conventions for associating a basic service with a SIP
Request-URI. MSML allows services to be dynamically applied and
changed by a Control Agent during the lifetime of the SIP dialog.
MSML has been designed to address the control and manipulation of
media processing operations (e.g., announcement, IVR, play and
record, ASR/TTS, fax, video), as well as control and relationships of
media streams (e.g., simple and advanced conferencing). It provides a
general-purpose media server control architecture. MSML can
additionally be used to invoke other more complex IVR languages such
as VoiceXML.
2. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [7].
3. Glossary
Media Server: a general-purpose platform for executing real-time
media processing tasks. This is a logical function that maps either
to a single physical device or to a portion of a physical device.
Media Server Client: an application which originates MSML requests to
a media server and also referred to as a Control Agent in this
specification.
Network Connection: a participant that represents the termination on
a media server of one or more RTP [15] sessions (for example audio
and video) associated with a call. Network connections are
established and removed using a session establishment protocol such
as SIP. An instance of a network connection is independent of MSML
processing instructions applied to it.
Dialog: an automated IVR participant. Examples of dialogs may be
announcement players, IVR interfaces, or voice recorders. Dialogs may
be defined in MSML or using VoiceXML [7].
Conference: an intermediary function that provides multimedia mixing
and other advanced conferencing services. This specification
Saleem & Sharratt Expires - August 2006 [Page 6]
Internet-draft Media Server Markup Language February 2006
(MSML)
currently considers conferences with audio and/or video media types,
but is extensible to other media types.
Identifier: a name that is used to refer to a specific instance of an
object on the media server, such as a conference or a dialog.
Identifiers are composed of one or more terms where each term
identifies an object class and instance.
Object: the generic term for a media server entity that terminates,
originates, or processes media. This specification defines four
classes of objects and specifies mechanisms to create them, join them
together, and destroy them.
Participant Object: an object in a media server that sources original
media in a call and/or receives and terminates media in a call.
Intermediary Object: an object in a media server that acts on media
within a call for the benefit of the participants.
Independent Object: an object that can exist on a media server
independent of other objects.
Operator: an intermediary object class that modifies or transforms a
media stream. Examples of operators may be audio gain controls, video
scaling, or voice masking. MSML defines operators as implicit
objects, which transform media when operations, such as gain control,
are applied to media streams.
Media Stream: a single media flow between two objects. A media stream
has a media type and may be unidirectional or bidirectional.
4. MSML SIP Usage
SIP is used to create and modify media sessions with a media server
according to the procedures defined in RFC 3261 [1]. Often, SIP third
party call control [16] will be used to create sessions to a media
server on behalf of end users. MSML is used to define and change the
service which a user connected to a media server will receive. MSML
clients are application servers, softswitches, or other forms of
control agents, and SHOULD have an authorized security relationship
with the media server. MSML itself does not define authorization
mechanisms.
MSML transactions are originated based upon events that occur in the
application domain. These events may be independent from any media or
user interaction. For example, an application may wish to play an
announcement to a conference warning that its scheduled completion
time is approaching. Applications themselves are structured in many
Saleem & Sharratt Expires - August 2006 [Page 7]
Internet-draft Media Server Markup Language February 2006
(MSML)
different ways. Their structure and requirements contribute to their
selection of protocols and languages. To accommodate differing
application needs, MSML has been designed to be neutral to other
languages and independent of the transport used to carry it.
Many alternatives exist for a transport mechanism for MSML. There may
be one or many transport channels used to carry MSML based upon the
requirements and structure of applications. SIP INVITE and INFO [17]
requests and responses have been chosen to carry MSML in this release
of the specification. INFO requests allow asynchronous mid-call
messages within SIP with few additional semantics. In addition, there
are existing widely deployed implementations of that method, it aids
in initial developments which are closely coupled with SIP session
establishment, and it allows MSML to be directly associated with user
dialogs when third party call control is used.
Although INFO is sometimes considered to not be a suitable general-
purpose transport mechanism for messages within SIP, there have been
proposals to make it more acceptable. MSML may evolve to include
other SIP usage and/or to work with other protocols or as a stand-
alone protocol established through SIP, in future releases of this
document.
MSML supports several models for client interaction. When clients use
3PCC to establish media sessions on behalf of end users, clients will
have a SIP dialog for each media session. MSML MAY be sent on these
dialogs. However the targets of MSML actions are not inferred from
the session associated with the SIP dialog. The targets of MSML
actions are always explicitly specified using identifiers as
previously defined.
An application, after interacting with a user, may want to affect
multiple objects within a media server. For example, tones or
messages are often played to a conference when connections are added
or removed. A separate message may also be played to a participant as
they are joined, or to moderators. Explicit identifiers, that is, not
inferred from a transport mechanism allow these multiple actions to
be easily grouped into a single transaction sent on any SIP dialog.
MSML also supports a model of dedicated control associations. This
supports decoupled application architectures where a client can
control media server services without also establishing all of the
media sessions itself. Control associations are created using SIP but
they do not have any associated media session. Although initially
INFO messages will be sent on this SIP dialog, just as with dialogs
associated with media sessions, it is possible that in the future,
the SIP dialog will be used to establish a separate control session
Saleem & Sharratt Expires - August 2006 [Page 8]
Internet-draft Media Server Markup Language February 2006
(MSML)
(defined in SDP [18]) that does not use SIP as the transport for MSML
messages.
A media server using MSML also sends asynchronous events to a client
using MSML scripts in SIP INFO. Events are sent based on previous
MSML requests and are sent within the SIP dialog on which the MSML
request that caused the event to be generated was received. If this
dialog no longer exists when the event is generated, the event is
discarded.
Events may be generated during the execution of a dialog created by a
<dialogstart> element. For example, dialogs can send events based on
user input. VoiceXML dialogs, on the other hand, generally interact
with other servers outside of MSML using HTTP.
An event is also generated when the execution of a dialog terminates,
either because of completion or failure. The exact information
returned is dependent on the dialog language, the capabilities of the
dialog execution environment, and what was requested by the dialog.
Both MSML and VoiceXML [7] allow information to be returned when they
exit. These events may be sent in a SIP INFO or a SIP BYE. SIP BYE is
used when the dialog itself specifies that the connection should be
disconnected, for example through the use of the <disconnect>
element.
Conferences may also generate events based upon their configuration.
An example of this is the notification of the set of active speakers.
5. Language Structure
5.1 Package Scheme
The primary mechanism for extending MSML is the "package". A package
is an integrated set of one or more XML schemas that define
additional features and functions via new or extended use of elements
and attributes. Each package, except for those defined in the current
document, is defined in a separate standards document, e.g., an
Internet Draft or an RFC. All packages, that extend the base MSML
functionality, MUST include references to the MSML base set of
schemas provided in the Internet drafts. A schema in a package MUST
only extend MSML, this is, it must not alter the existing
specification.
A particular MSML script will include references to all the schemas
defining the packages whose elements and attributes it makes use of.
A particular script MUST reference MSML base and optionally extension
package(s). See IANA Considerations section.
Saleem & Sharratt Expires - August 2006 [Page 9]
Internet-draft Media Server Markup Language February 2006
(MSML)
Each package MUST define its own namespace so that elements or
attributes with the same name in different packages do not conflict.
A script using a particular element or attribute MUST prefix the
namespace name on that element or attribute's name if it is defined
in a package (as opposed to being defined in the base).
MSML consists of a core package which provides structure without
support for any specific feature set. Additional packages, relying on
the core package, provide functional features. Any combination of
additional packages may be used along with the core package. The
following describes the set of MSML packages defined in this
document.
+----------------------------------------------+
| MSML Core |
+----------------------------------------------+
/ \
+--------+ +--------+
| Dialog | | Conf |
| Core | | Core |
- - +--------+ - - - - - - - - +--------+
/ / \ \ \
+--------+ +--------+ +---------+ +------+ +------+
| Dialog | | Dialog | |Dialog | |Dialog| |Dialog|
| Base | | Group | |Transform| |Speech| |Fax |
+--------+ +--------+ +---------+ +------+ +------+
o MSML Core package (Mandatory)
Describes the minimum base framework which MUST be implemented
to support additional core packages.
o MSML Conference Core package (Conditionally Mandatory, for
Conferencing)
Describes the audio and multimedia basic and advanced
conferencing package, which MAY be implemented.
o MSML Dialog Core package (Conditionally Mandatory, for Dialogs)
Describes the dialog core package which MUST be implemented for
any dialog services. However, systems supporting conferencing
only, MAY omit support for MSML dialogs. The MSML dialog core
package specifies the framework within which additional dialog
packages are supported. The MSML dialog base package MUST be
supported, while all other dialog packages MAY be supported.
Saleem & Sharratt Expires - August 2006 [Page 10]
Internet-draft Media Server Markup Language February 2006
(MSML)
o MSML Dialog Base package (Conditionally Mandatory, for
Dialogs)
o MSML Dialog Group package (Optional)
o MSML Dialog Transform package (Optional)
o MSML Dialog Fax Detection package (Optional)
o MSML Dialog Fax Send/Receive package (Optional)
o MSML Dialog Speech package (Optional)
The formal process for defining extensions to MSML Dialogs is to
define a new package. The new package MUST provide a text description
of what extensions are included and how they work. It MUST also
define an XML schema file (if applicable) that defines the new
package (which may be through extension, restriction of an existing
package, or a specific profile of an existing package). Dependencies
upon other packages MUST be stated. For example a package that
extends or restricts has a dependency on the original package
specification. Finally, the new package MUST be assigned a unique
name and version.
The types of things which can be defined in new packages are:
o new primitives
o extensions to existing primitives (events, shadow variables,
attributes, content)
o new recognition grammars for existing primitives
o new markup languages for speech generation
o languages for specifying a topology schema
o new pre-defined topology schemas
o new variables / segment types (sets & languages)
o new control flow elements
MSML Packages are assembled together to form a specific MSML profile
that is shared between different implementations. The base MSML
Dialog profiles which are defined in this document consist of the
MSML Core package, MSML Dialog Core package, MSML Dialog Base
Saleem & Sharratt Expires - August 2006 [Page 11]
Internet-draft Media Server Markup Language February 2006
(MSML)
package, MSML Dialog Group package, MSML Transform package, MSML Fax
packages, and the MSML Speech package.
MSML extension packages, which define primitives, MUST define the
following for each primitive within the package:
o the function which the primitive performs
o the attributes which may be used to tailor its behavior
o the events which it is capable of understanding
o the shadow variables which provide access to information
determined as a result of the primitive's operation.
The mechanism used to insure that a media server and its client share
a compatible set of packages is not defined. Currently it is expected
that provisioning will be used, possibly coupled with a future
auditing capability. Additionally, when used in SIP networks,
packages could be defined using feature tags and the procedures
defined for Indicating User Agent Capabilities in SIP [2] used to
allow a media server to describe its capabilities to other user
agents and its domain registrar.
5.2 Profile Scheme
Not all devices and applications using MSML will need to support the
entire MSML schema. For example, a media processing device might
support only audio announcements, only audio simple conferencing, or
only multimedia IVR. It is highly desirable to have a system for
describing what portion of MSML a particular media processing device
or Control Agent supports.
The Package scheme described earlier allows MSML functionality to be
functionally grouped, relying on the MSML core package. This scheme
allows a portion of the complete MSML specification to be
implemented, on a per package basis and also creates a framework for
future extension packages. However, within a given package, in some
cases, only a subset of the package functionality may be required. In
order to support subsets of packages, with greater degree of
granularity than at the package level, a profile scheme is required.
MSML package profiles would identify a subset of a given MSML package
with specific definitions of elements and attributes. Each MSML
package profile MUST be accompanied by one or more corresponding
schemas. To use the examples above, there could be an audio
announcements profile of the MSML Dialog Base package, an audio
Saleem & Sharratt Expires - August 2006 [Page 12]
Internet-draft Media Server Markup Language February 2006
(MSML)
simple conferencing profile of the MSML Conference Core package, and
a multimedia IVR profile of the MSML Dialog Base package.
MSML package profiles MUST be published separately from the MSML
specification, in one or more standards documents (e.g., Internet
Drafts or RFCs) dedicated to MSML package profiles. Profiles would
not be registered with IANA and any organization would additionally
be free to create its own profile(s) if required.
6. Execution Flow
MSML assumes a model where there is a single control context within a
media server for MSML processing. That context may have one or many
SIP [1] dialogs associated with it. It is assumed that any SIP
dialogs associated with the MSML control context have been
authorized, as appropriate, by mechanisms outside the scope of MSML.
A media server control context maintains information about the state
of all media objects and media streams within a media server. It
receives and processes all MSML requests from authorized SIP dialogs
and receives all events generated internally by media objects and
sends them on the appropriate SIP dialog. An MSML request is able to
create new media objects and streams, and to modify or destroy any
existing media objects and streams.
An MSML request may simply specify a single action for a media server
to undertake. In this case, the document is very similar to a simple
command request. Often, though, it may be more natural for a client
to request multiple actions at one time, or the client would like
several actions to be closely coordinated by the media server.
Multiple MSML elements received in a single request MUST be processed
sequentially in document order.
An example of the first scenario would be to create a conference and
join it with an initial participant. An example of the second case
would be to unjoin one or more participants from a main conference
and join them to a sidebar conference. In the first scenario, network
latencies may not be an issue, but it is simpler for the client to
combine the requests. In the second case, the added network latency
between separate requests could mean perceptible audio loss to the
participant.
Each MSML request is processed as a single transaction. A media
server MUST ensure that it has the necessary resources available to
carry out the complete transaction before executing any elements of
the request. If it does not have sufficient resources, it MUST return
a 520 response and MUST NOT execute the transaction.
Saleem & Sharratt Expires - August 2006 [Page 13]
Internet-draft Media Server Markup Language February 2006
(MSML)
The MSML request MUST be checked for well-formedness and validated
against the schema prior to executing any elements. This allows XML
[4] errors to reported immediately and minimizes failures within a
transaction and the corresponding execution of only part of the
transaction.
Each element is expected to execute immediately. Elements such as
<dialogstart>, which take an unpredictable amount of time, are
"forked" and executed in a separate thread (see MSML Dialog
packages). Once successfully forked, execution continues with the
element following the </dialogstart>. As such, MSML does not provide
mechanisms to sequence or coordinate other operations with dialog
elements.
Processing within a transaction MUST stop if any errors occur.
Elements that were executed prior to the error are not rolled back.
It is the responsibility of the client to determine appropriate
actions based upon the results indicated in the response. Most
elements MAY contain an optional "mark" attribute. The value of that
attribute from the last successfully executed element MUST be
returned in an error response. Note that errors that occur during the
execution of a dialog occur outside the context of an MSML
transaction. These errors will be indicated in an asynchronous event.
Transaction results are returned as part of the SIP request response.
The transaction results indicate the success or failure of the
transaction. The result MUST also include identifiers for any objects
created by a media server for which the client did not provide an
instance name. Additionally, if the transaction fails, the reason for
the failure MUST be returned, as well as an indication of how much of
the transaction was executed before the failure occurred SHOULD be
returned.
7. Media Server Object Model
Media servers are general-purpose platforms for executing real-time
media processing tasks. These tasks range in complexity from simple
ones such as serving announcements, to complex ones, such as speech
interfaces, centralized multimedia conferencing, and sophisticated
gaming applications.
Calls are established to a media server using SIP. Clients will often
use SIP third party call control (3PCC) [16] to establish calls to a
media server on behalf of end users. However MSML does not require
that 3PCC be used; only that the client and the media server share a
common identifier for the call and its associated RTP [15] sessions.
Saleem & Sharratt Expires - August 2006 [Page 14]
Internet-draft Media Server Markup Language February 2006
(MSML)
Objects represent entities which source, sink, or modify media
streams. A media streams is a bidirectional or unidirectional media
flow between objects on a media server. The following subsections
define the classes of objects that exist on a media server and the
way these are identified in MSML.
7.1 Objects
A media object is an endpoint of one or more media streams. It may be
a connection that terminates RTP sessions from the network or a
resource that transforms or manipulates media. MSML defines four
classes of media objects. Each class defines the basic properties of
how object instances are used within a media server. However most
classes require that the function of specific instances be defined by
the client, using MSML or other languages such as VoiceXML.
The following classes of media processing objects are defined. The
class names are given in parentheses:
o network connection (conn)
o conference (conf)
o dialog (dialog)
o operator (oper)
Network connection is an abstraction for the media processing
resources involved in terminating the RTP session(s) of a call. For
audio services a connection instance presents a full-duplex audio
stream interface within a media server. Multimedia connections have
multiple media streams of different media types, each corresponding
to an RTP session. Network connections get instantiated through SIP
[1].
A conference represents the media resources and state information
required for a single logical mix of each media type in the
conference (e.g. audio and video). MSML models multiple mixes/views
of the same media type as separate conferences. Each conference has
multiple inputs. Inputs may be divided into classes that allow an
application to request different media treatment for different
participants. For example, the video streams for some participants
may be assigned to fixed regions of the screen while those for other
participants may only be shown when they are speaking.
Saleem & Sharratt Expires - August 2006 [Page 15]
Internet-draft Media Server Markup Language February 2006
(MSML)
A conference has a single logical output per media type. For each
participant, it consists of the audio conference mix, less any
contributed audio of the participant, and the video mix shared by all
conference participants. Video conferences using voice activated
switching have an optional ability to show the previous speaker to
the current speaker.
Conferences are instantiated using the <createconference> element.
The content of the <createconference> element specifies the
parameters of the audio and/or video mixes.
Dialogs are a class of objects that represent automated participants.
They are similar to network connections from a media flow perspective
and may have one or more media streams as the abstraction for their
interface within a media server. Unlike connections however, dialogs
are created and destroyed through MSML, and the media server itself
implements the dialog participant. Dialogs are instantiated through
the <dialogstart> element. Contents of the <dialogstart> element
define the desired or expected dialog behavior. Dialogs may also be
invoked by referencing VoiceXML as the dialog description language.
Operators are implicit functions that are used to filter or transform
a media stream. The function that an instance of an operator fulfills
is defined as a property of the media stream. Operators may be
unidirectional or bidirectional and have a media type. Unidirectional
operators reflect simple atomic functions such as automatic gain
control, filtering tones from conferences, or applying specific gain
values to a stream. Unidirectional operators have a single media
input, which is connected to the media stream from one object, and a
single media output, which is connected to the media stream of a
different object.
Bidirectional operators have two media inputs and two media outputs.
One media input and output is associated with the stream to one
object and the other input and output is associated with a stream to
a different object. Bidirectional objects may treat the media
differently in each direction. For example, an operator could be
defined which changed the media sent to a connection based upon
recognized speech or DTMF received from the connection. Operators are
implicitly instantiated when streams are created or modified using
the elements <join> element and elements <modifystream> respectively.
The relationships between the different object classes is shown in
the figure below.
Saleem & Sharratt Expires - August 2006 [Page 16]
Internet-draft Media Server Markup Language February 2006
(MSML)
+--------------------------------------+
| Media Server |
| |
|------+ ,---. |
| | +------+ / \ |
<== RTP ==>| conn |<---->| oper |<---->( conf ) |
| | +------+ \ / |
|------+ `---' |
| ^ ^ |
| | | |
| | +------+ +------+ | |
| | | | | | | |
| +-->|dialog| |dialog|<---+ |
| | | | | |
| +------+ +------+ |
+--------------------------------------+
A single, full-duplex instance of each object class is shown together
with common relationships between them. An operator (such as gain) is
shown between a connection and a conference and dialogs are shown
participating both with an individual connection and with a
conference. The figure is not meant to imply only one to one
relationships. Conferences will often have hundreds of participants,
and either connections or conferences may be interacting with more
than one dialog. For example, one dialog may be recording a
conference while other dialogs announce participants joining or
leaving the conference.
7.2 Identifiers
Objects are referenced using identifiers that are composed of one or
more terms. Each term specifies an object class and names a specific
instance within that class. The object class and instance are
separated by a colon ":" in an identifier term.
Identifiers are assigned to objects when they are first created. In
general, either the MSML client or a media server may specify the
instance name for an object. Objects for which a client does not
assign an instance name will be assigned one by a media server. Media
server assigned instance names are returned to the client as a
complete object identifier in the response to the request that
created the object.
It is meaningful for some classes of objects to exist independently
on a media server. Network connections may be created through SIP at
any time. MSML can then be used to associate their media with other
objects as required to create services. Conferences may be created
Saleem & Sharratt Expires - August 2006 [Page 17]
Internet-draft Media Server Markup Language February 2006
(MSML)
and have specific resources reserved waiting for participant
connections.
Objects from these two classes, connections and conferences, are
considered independent objects since they can exist on a standalone
basis. Identifiers for independent objects consist of single term as
defined above. For example, identifiers for a conference and
connection could be "conf:abc" or "conn:1234" respectively. Clients
which choose to assign instance names to independent objects must use
globally unique instance names. One way to create globally unique
names is to include the domain name of the client as part of the
name.
Dialogs are created to provide a service to independent objects.
Dialogs may act as a participant in a conference or interact with a
connection similar to a two participant call. Dialogs depend upon the
existence of independent objects and this is reflected in the
composition of their identifiers. Operators modify the media flow
between other objects, such as application of gain between a
connection and a conference. As operators are merely media transform
primitives defined as properties of the media stream, they are not
represented by identifiers and created implicitly.
Identifiers for dialogs are composed of a structured list of slash
('/') separated terms. The left-most term of the identifier must
specify a conference or connection. This serves as the root for the
identifier. An example of an identifier for a dialog acting as a
conference participant could be:
conf:abc/dialog:recorder
All objects except connections are created using MSML. Connections
are created when media sessions get established through SIP. There
are several options clients and media servers can use to establish a
shared instance name for a connection and its media streams.
When media servers support multiple media types, the instance name
SHOULD be a call identifier that can be used to identify the
collection of RTP sessions associated with a call. When MSML is used
in conjunction with SIP and third party call control, the call
identifier MUST be the same as the local tag assigned by the media
server to identify the SIP dialog. This will be the tag the media
server adds to the "To" header in its response to an initial invite
transaction. RFC 3261 requires the tag values to be globally unique.
An example of a connection identifier is: conn:74jgd63956ts.
Saleem & Sharratt Expires - August 2006 [Page 18]
Internet-draft Media Server Markup Language February 2006
(MSML)
With third party call control, the MSML client acts as a back to back
user agent (B2BUA) to establish the media sessions. SIP dialogs are
established between the client and the media server allowing the use
of the media server local tag as a connection identifier. If third
party call control is not used, a SIP event package MAY be used to
allow a media server to notify new sessions to a client that has
subscribed to this information.
Identifiers as described above allow every object in a media server
to be uniquely addressed. They can also be used to refer to multiple
objects. There are two ways in which this can currently be done:
wildcards
common instance names
An identifier can reference multiple objects when a wildcard is used
as an instance name. MSML reserves the instance name comprised of a
single asterisk ('*') to mean all objects that have the same
identifier root and class. Instance names containing an asterisk
cannot be created. Wildcards MUST only be used as the right most term
of an identifier and MUST NOT be used as part of the root for dialog
identifiers. Wildcards are only allowed where explicitly indicated
below.
The following are examples of valid wildcards:
conf:abc/dialog:*
conn:*
Examples of illegal wildcard usage are:
conf:*/dialog:73849
Although identifiers share a common syntax, MSML elements restrict
the class of objects which are valid in a given context. As an
example, although it is valid to join two connections together, it is
not valid to join two IVR dialogs.
8. MSML Core Package
This section describes the core MSML package which MUST be supported
in order to use any other MSML packages. The core MSML package
defines a framework, without explicit functionality, over which
functional packages are used.
Saleem & Sharratt Expires - August 2006 [Page 19]
Internet-draft Media Server Markup Language February 2006
(MSML)
8.1 <msml>
<msml> is the root element. When received by a media server, it
defines the set of operations that form a single MSML request.
Operations are requested by the contents of the element. Each
operation MAY appear zero or more times as children of <msml>.
Specific operations are defined within the Conference package and in
the set of Dialog packages.
The results of a request or the contents of events sent by a media
server are also enclosed within the <msml> element. The results of
the transaction are included as a body in the response to the SIP
request that contained the transaction. This response will contain
any identifiers that the media server assigned to newly created
objects. All messages that a media server generates are correlated to
an object identifier. Objects and identifiers are discussed in
section 7 (Media Server Object Model).
Attributes:
version: "1.1" Mandatory
8.2 <send>
Events are used to affect the behavior of different objects within a
media server. The <send> element is used to send an event to the
specified recipient within the Media Server.
Attributes:
event: the name of an event. Mandatory.
target: an object identifier. When the identifier is for a
dialog, it may optionally be appended with a slash "/" followed
by the target to be included in a MSML Dialog <send>.
Mandatory.
valuelist: a list of zero or more parameters that are included
with the event.
mark: a token that can be used to identify execution progress
in the case of errors. The value of the mark attribute from the
last successfully executed MSML element is returned in an error
response. Therefore the value of all mark attributes within an
MSML document should be unique.
Saleem & Sharratt Expires - August 2006 [Page 20]
Internet-draft Media Server Markup Language February 2006
(MSML)
8.3 <result>
The <result> element is used to report the results of an MSML
transaction. It is included as a body in the final response to the
SIP request which initiated the transaction. An optional child
element <description> may include text which expands on the meaning
of error responses. Response codes are defined in section 11
(Response Codes).
attributes:
response: a numeric code indicating the overall success or
failure of the transaction, and in the case of failure, an
indication of the reason. Mandatory.
mark: in the case of an error, the value of the mark attribute
from the last successfully executed element that included the
mark attribute.
In the case of failure, a description of the reason SHOULD be
provided using the child element <description>.
Three other child elements allow the response to include identifiers
for objects created by the request but which did not have instance
names specified by the client. Those elements are <confid> and
<dialogid>, for objects created though a <createconference> and
<dialogstart> respectively.
8.4 <event>
The <event> element is used to notify an event to a media server
client. Three types of events are defined by MSML Core package;
"msml.dialog.exit", "msml.conf.nomedia", and "msml.conf.asn". These
correspond to the termination of an executing dialog, a conference
being automatically deleted when the last participant has left, and
the notification of the current set of active speakers for a
conference, respectively. Events may also be generated by an
executing dialog. In this case the event type is specified by the
dialog. (see MSML Dialog Core Package <send>).
attributes:
name: the type of event. If the event is generated because of
the execution MSML Dialog <send>, the value MUST be the value
of the "event" attribute from the <send> element within the
MSML Dialog Core package. If the event is generated because of
the execution of an <exit>, the value MUST be "moml.exit". If
the event is generated because of the execution of a
Saleem & Sharratt Expires - August 2006 [Page 21]
Internet-draft Media Server Markup Language February 2006
(MSML)
<disconnect>, the value MUST be "moml.disconnect". If the event
is generated because of an error, the value must be
"moml.error". Mandatory.
id: the identifier of the conference or dialog that generated
the event or caused the event to be generated. Mandatory.
<event> has two children, <name> and <value>, which contain the
name and value respectively of each namelist item associated
with the event.
9. MSML Conference Core Package
9.1 Conferences
A conference has a mixer for each type of media that the conference
supports. Each mix has a corresponding description that defines how
the media from participants contributes to that mix. A mixer has
multiple inputs that are combined in a media specific way to create a
single logical output.
The elements that describe the mix for each media type are called
mixer description elements. They are:
<audiomix> defines the parameters for mixing audio media.
<videolayout> defines the composition of a video window.
These elements, defined in sections 9.6 (Audio Mix) and 9.7 (Video
Layout) respectively, are used as content of the <createconference>
element to establish the initial properties of a conference. The
elements are used within the <modifyconference> element to change the
properties of a conference once it has been created, or within the
<destroyconference> element to remove individual mixes from the
conference.
Conferences may be terminated by an MSML client using the
<destroyconference> element to remove the entire conference or by
removing the last mixer(s) associated with the conference.
Conferences can also be terminated automatically by a media server
based on criteria specified when the conference is created. When the
conference is deleted, any remaining participants will have their
associated SIP dialogs left unchanged or deleted based on the value
of the "term" attribute specified when the conference was created.
Saleem & Sharratt Expires - August 2006 [Page 22]
Internet-draft Media Server Markup Language February 2006
(MSML)
9.2 Media Streams
Objects have at least one media input and output for each type of
media that they support. Each object class defines the number of
inputs and outputs objects of that class support. Media streams are
created when objects are joined, either explicitly using <join>, or
implicitly when dialogs are created using <dialogstart>. Dialog
creation has two stages, allocating and configuring the resources
required for the dialog instance, and implicitly joining those
resources to the dialog target during the dialog execution. Refer to
MSML Dialog Base package.
A join operation by default creates a bidirectional audio stream
between two objects. Video and unidirectional streams may also be
created. A media stream is created by connecting the output from one
object to the input of another object and vice versa (assuming a
bidirectional or full-duplex join).
Many objects may only support a single input for each type of media.
Within this specification, only the conference object class supports
an arbitrary number of inputs. When a stream is requested to be
created to an object that already has a stream of the same type
connected to its single input, the result of the request depends upon
the type of the media stream.
Audio mixing is done by summing audio signals. Automatically mixing
audio streams has common and straight forward applications. For
example, the ability to bridge two streams allows for the easy
creation of simple three-way calls or to bridge private announcements
with a [whispered] conference mix for an individual participant. In
the case of general conferences however, an MSML client SHOULD create
an audio conference and then join participants to the conference.
Conference mixers SHOULD subtract the audio of each participant from
the mix so that they do not hear themselves.
A media server that receives a request that requires joining an audio
stream to the single audio input of an object that already has an
audio stream connected, SHOULD automatically bridge the new stream
with the existing stream, creating a mix of the two audio streams.
The maximum number of streams that may be bridged in this manner is
implementation-specific. It is RECOMMENDED that a media server
support bridging at least two streams. A media server that cannot
bridge a new stream with any existing streams MUST fail the operation
requesting the join.
Unlike audio mixing, there are many different ways that two video
streams may be combined and presented. For example, they may be
presented side by side in separate panes, picture in picture, or in a
Saleem & Sharratt Expires - August 2006 [Page 23]
Internet-draft Media Server Markup Language February 2006
(MSML)
single pane which displays only a single stream at a time based on a
heuristic such as active speaker. Each of these options creates a
very different presentation and require significantly different media
resources.
A join operation does not describe how a new stream can be combined
with an existing stream. Therefore automatic bridging of video is not
supported. A media server MUST fail requests to join a new video
stream to an object that only supports a single video input and
already has a video stream connected to that input. For an object to
have multiple video streams joined to it, the object itself must be
capable in supporting multiple video streams. Conference objects can
support multiple video streams and provide a way to specify the
mixing presentation for the video streams.
A media server MUST NOT establish any streams unless the media server
is able to create all the streams requested by an operation. Streams
are only able to be created if both objects support a media type and
at least one of the following conditions is true:
1. each object that is to receive media is not already receiving a
stream of that type.
2. any object that is to receive media and is already receiving a
stream of that type supports receiving an additional stream of
that type. The only class of objects defined in this
specification that directly support receiving multiple streams
of the same type are conferences.
3. the media server is able to automatically bridge media streams
for an object that is to receive media and that is already
receiving a stream of the requested type. The only type of
media defined in this specification that MAY be automatically
bridged is audio.
The directionality of media streams associated with a connection are
modeled independently from what SDP [18] allows for the corresponding
RTP [15] sessions. Media servers MUST respect the SDP in what they
actually transmit but MUST NOT allow the SDP to affect the
directionality when joining streams internal to the media server.
9.3 <createconference>
<createconference> is used to allocate and configure the media mixing
resources for conferences. A description of the properties for each
type of media mix required for the conference is defined within the
content of the <createconference> element. Mixer descriptions are
described in Audio Mix and Video Layout sections. When no mixer
Saleem & Sharratt Expires - August 2006 [Page 24]
Internet-draft Media Server Markup Language February 2006
(MSML)
descriptions are specified, the default behavior MUST be equivalent
to inclusion of a single <audiomix>.
Clients can request that a media server automatically delete a
conference when a specified condition occurs by using the
"deletewhen" attribute. A value of "nomedia" indicates that the
conference MUST be deleted when no participants remain into the
conference. When this occurs, an "msml.conf.nomedia" event MUST be
notified to the MSML client. A value of "nocontrol" indicates the
conference MUST be deleted when the SIP [1] dialog that carries the
<createconference> element is terminated. When this occurs, a media
server MUST terminate all participant dialogs by sending a BYE for
their associated SIP dialog. A value of "never" MUST leave the
ability to delete a conference under the control of the MSML client.
attributes:
name: the instance name of the conference. If the attribute is
not present, the media server MUST assign a globally unique
name for the conference. If the attribute is present but the
name is already in use, an error (432) will result and MSML
document execution MUST stop. Events which the conference
generates use this name as the value of their "id" attribute
(see section 5.6.2 (<event>)).
deletewhen: defines whether a media server should automatically
delete the conference. Possible values are "nomedia",
"nocontrol", and "never". Default is "nomedia".
term: when true, the media server MUST send a BYE request on
all SIP dialogs still associated with the conference when the
conference is deleted. Setting term equal to false allows
clients to start dialogs on connections once the conference has
completed. Default true.
mark: a token which MAY be used to identify execution progress
in the case of errors. The value of the mark attribute from the
last successfully executed MSML element is returned in an error
response. Therefore the value of all mark attributes within an
MSML document should be unique.
An example of creating an audio conference is shown below. This
conference allows at most two participants to contend to be heard and
reports the set of active speakers no more frequently than every ten
seconds.
<?xml version="1.0" encoding="UTF-8"?>
Saleem & Sharratt Expires - August 2006 [Page 25]
Internet-draft Media Server Markup Language February 2006
(MSML)
<msml version="1.1">
<createconference name="example">
<audiomix>
<n-loudest n="3"/>
<asn ri="10s"/>
</audiomix>
</createconference>
</msml>
9.3.1 <reserve>
Conference resources may be reserved by including the <reserve>
element as a child of <createconference>. <reserve> allows the
specification of a set of resources which a media server will reserve
for the conference. Any requests for resources beyond those that have
been reserved should be honored on a best-effort basis by a media
server.
attributes:
required: boolean that specifies whether <createconference>
should fail if the requested resources are not available. When
set to false, the conference will be created, with no reserved
resources, if the complete reservation cannot be honored.
Default true.
9.3.1.1 <resource>
The resources to be reserved are defined using <resource>. The
contents of these elements describe a resource that is to be
reserved. Descriptions are implementation-dependent. Media servers
that support MSML Dialogs may use the elements from that package as
the basis for resource descriptions. Each resource element may use
the attribute "n" to define the quantity of the resource to reserve.
For example, the following creates a conference and reserves two
types of resources. One resource element may represent resources that
are shared by all participants of the conference while the other may
represent resources that are reserved for each of the expected
participants.
attributes:
Saleem & Sharratt Expires - August 2006 [Page 26]
Internet-draft Media Server Markup Language February 2006
(MSML)
n: number of resources to be reserved. Default 1.
type: specifies whether the resource is to be reserved by each
individual participant or reserved as a shared conference
resource. Valid values for this attribute are “individual” or
“shared”. Default “individual”.
<createconference>
<reserve>
<resource n="20">
<!--description of resources used by each participant-->
</resource>
<resource n="2" type=”shared”>
<!--description of the shared conference resources-->
</resource>
</reserve>
</createconference>
9.4 <modifyconference>
All of the properties of an audio mix or the presentation of a video
mix may be changed during the life of a conference using the
<modifyconference> element. Changes to an audio mix are requested by
including an <audiomix> element as a child of <modifyconference>.
This may also be used to add an audio mixer to the conference if none
was previously allocated. Changes to a video presentation are
requested by including a <videolayout> element as a child of
<modifyconference>. Similar to an audio mixer, this may be used to
add a video mixer if none was previously allocated.
Mixers are removed by including a mixer description element within
<destroyconference/>.
Features and presentation aspects are enabled/added or modified by
including the element(s) that define the feature or presentation
aspect within a mixer description. The complete specification of the
element must be included just as it would be included when the
conference is created. The new definition completely replaces any
previous definition that existed. Only things that are defined by
elements included in the mixer descriptions are affected. Any
existing configuration aspects of a conference, which are not
Saleem & Sharratt Expires - August 2006 [Page 27]
Internet-draft Media Server Markup Language February 2006
(MSML)
specified within the <modifyconference/> element, MUST maintain their
current state in the Media Server.
For example, if an MSML client wanted to change the minimum reporting
interval for active speaker notification from that shown in the
Conference Examples section (<createconference>) it would send the
following to the media server:
<?xml version="1.0" encoding="UTF-8"?>
<msml version="1.1">
<modifyconference id="conf:example">
<audiomix>
<asn ri="4"/>
</audiomix>
</modifyconference>
</msml>
This would also enable active speaker notification if it had not
previously been enabled. The N-loudest mixing is unaffected.
Multiple elements MAY be included in the mixer descriptions similar
to when conferences are created. For example, in a video conference,
the video mix description (<videolayout>) could specify that the
layout of the video being displayed should change such that the
regions currently displaying participants get smaller and new
region(s) are created to support additional participants. A media
server MUST make all of the requested changes or none of the
requested changes.
Additional examples of modifying conferences are presented in the
Conference Examples section.
attributes:
id: the identifier for a conference. Wildcards MUST NOT be
used. Mandatory.
mark: a token which can be used to identify execution progress
in the case of errors. The value of the mark attribute from the
last successfully executed MSML element is returned in an error
response. Therefore the value of all "mark" attributes within
an MSML document SHOULD be unique.
Saleem & Sharratt Expires - August 2006 [Page 28]
Internet-draft Media Server Markup Language February 2006
(MSML)
9.5 <destroyconference>
Destroy conference is used to delete mixers or to delete the entire
conference and all state and shared resources. When a mixer is
removed, all of the streams joined to that mixer are unjoined. When a
conference is destroyed, SIP dialogs for any remaining participants
MUST be maintained or removed based on the value of the "term"
attribute when the conference was created.
When there is no element content, <destroyconference/> deletes the
entire conference. Individual mixer(s) are removed by including a
mixer description element identifying the mix(es) to be removed as
content to <destroyconference/>. <audiomix/> is used remove audio
mixers and <videolayout/> is used remove video mixers. When one or
more mixer descriptions are specified, then Media Server MUST only
delete the specified mixer and MUST NOT affect any other existing
mixers. When <audiomix/> or <videolayout/> are identified for
individual removal, other feature aspects of the mix MUST NOT be
included. If specified, the Media Server MUST ignore any such
elements. When the last mixer is removed from a conference, a media
server MUST remove all conference state, leaving or removing any
remaining SIP dialogs as described above.
attributes:
id: the identifier for a conference. Mandatory.
mark: a token which can be used to identify execution progress
in the case of errors. The value of the mark attribute from the
last successfully executed MSML element is returned in an error
response. Therefore the value of all "mark" attributes within
an MSML document SHOULD be unique.
9.6 <audiomix>
The properties of the overall audio mix are specified using the
<audiomix> element.
Attributes:
id: an optional identifier for the audio mix.
An example of the description for an audio mix is:
<audiomix id="mix1">
<asn ri="10s"/>
<n-loudest n="3">
Saleem & Sharratt Expires - August 2006 [Page 29]
Internet-draft Media Server Markup Language February 2006
(MSML)
</audiomix>
9.6.1 <n-loudest>
The <n-loudest> element defines that participants contend to be
included in the conference mix based upon their audio energy. When
the element is not present, all participants are mixed.
Attributes:
n: the number of participants that will be included in the
audio mix based upon having the greatest audio energy.
9.6.2 <asn>
The <asn> element enables notification of active speakers. Active
speakers MUST be notified using the <event> element with an event
name of "msml.conf.asn". The namelist of the event consists of the
set of active speakers. The name of each item is the string "speaker"
with a value of the connection identifier for the connection.
Attributes:
ri: the minimum reporting interval defines the minimum duration
of time which must pass before changes to active speakers will
be reported. A value of zero disables active speaker
notification.
An example of an active speaker notification is:
<event name="msml.conf.asn" id="conf:example">
<name>speaker</name>
<value>conn:hd93tg5hdf</value>
<name>speaker</name>
<value>conn:w8cn59vei7</value>
<name>speaker</name>
<value>conn:p78fnh6sek47fg</value>
</event>
Saleem & Sharratt Expires - August 2006 [Page 30]
Internet-draft Media Server Markup Language February 2006
(MSML)
9.7 <videolayout>
A video layout is specified using the <videolayout> element. It is
used as a container to hold elements that describe all of the
properties of a video mix. The parameters of the window that displays
the video mix are defined by the <root> element. When the video mix
in composed of multiple panes, the location and characteristics of
the panes are defined by one or more <region> elements. A <region>
element is not required when only a single video stream is displayed
at one time and none of the visual attributes of regions are
required.
Some regions may be used to display a video stream based on a
selection criteria rather than having a video stream of a single
participant continuously presented in the region. One such an example
is a distance learning lecture where the instructor sees each of the
students periodically displayed in a region. When a region is used to
display one of a number of streams, it is placed as a child of a
<selector> element.
Attributes:
type: specifies the language used to define the layout. Layouts
defined using MSML MUST use the value "text/msml-basic-layout".
This is the same convention as defined for the layout package
from the W3C SMIL 2.0 specification [19]. The default when
omitted is "text/msml-basic-layout".
id: an optional identifier for the video layout.
9.7.1 <root>
The <root> element describes the root window or virtual screen in
which the conference video mix will be displayed. Simple conferences
can display participant video directly within the root window but
more complex conferences will use regions for this purpose. Areas of
the window which are not used to display video will show the root
window background.
All video presentations require a root window. It MUST be present
when a video mix is created and it cannot be deleted, however its
attributes MAY be changed using the <modifyconference> element.
Attributes:
size: the size of the root window specified as one of the five
standard common intermediate formats (e.g. CIF, QCIF, etc.).
Saleem & Sharratt Expires - August 2006 [Page 31]
Internet-draft Media Server Markup Language February 2006
(MSML)
backgroundcolor: the color for the root window background
defined using the values for the "background-color" property of
the CSS2 specification [20].
backgroundimage: the URI for an image to be displayed as the
root window background. Transparent portions of the image allow
the background color to show through.
9.7.2 <region>
<region> elements define video panes that are used to display
participant video streams. Regions are rendered on top of the root
window.
The size of a region is specified relative to the size of the root
window using the "relativesize" attribute. Relative sizes are
expressed as fractions (e.g. 1/4, 1/3) that preserve the aspect ratio
of the original video stream while allowing for efficient scaling
implementations.
Regions are located on the root window based on the value of the
position attributes "top" and "left". These attributes define the
position of the top left corner of the region as an offset from the
top left corner of the root window. Their values may be expressed
either as a number of pixels or as a percent of the vertical or
horizontal dimension of the root window. Percent values are appended
with a percent ('%') character. Percent values of "33%" and "67%"
should be interpreted as "1/3" and "2/3" to allow easy alignment of
regions whose size is expressed relative to the size of the root
window.
An example of a video layout with six regions is:
+-------+---+
| | 2 |
| 1 +---+
| | 3 |
+---+---+---+
| 6 | 5 | 4 |
+---+---+---+
<videolayout type="text/msml-basic-layout">
<root size="CIF"/>
<region id="1" left="0" top="0" size="2/3"/>
<region id="2" left="67%" top="0" size="1/3"/>
Saleem & Sharratt Expires - August 2006 [Page 32]
Internet-draft Media Server Markup Language February 2006
(MSML)
<region id="3" left="67%" top="33%" size="1/3">
<region id="4" left="67%" top="67%" size="1/3"/>
<region id="5" left="33%" top="67%" size="1/3"/>
<region id="6" left="0" top="67%" size="1/3"/>
</videolayout>
The area of the root window covered by a region is a function of the
region's position and its size. When areas of different regions
overlap, they are layered in order of their "priority" attribute. The
region with the highest value for the "priority" attribute is below
all other regions and will be hidden by overlapping regions. The
region with the lowest non-zero value for the "priority" attribute is
on top of all other regions and will not be hidden by overlapping
regions. The priority attribute may be assigned values between 0 and
1. A value of zero disables the region, freeing any resources
associated with the region, and unjoining any video stream displayed
in the region.
Regions that do not specify a priority will be assigned a priority by
a media server when a conference is created. The first region within
the <videolayout> element that does not specify a priority will be
assigned a priority of one, the second a priority of two, etc. In
this way, all regions that do not explicitly specify a priority will
be underneath all regions that do specify a priority. As well, within
those regions that do not specify a priority, they will be layered
from top to bottom, in the order they appear within the <videolayout>
element.
For example, if a layout was specified as follows:
<videolayout>
<root size="CIF"/>
<region id="a" ... priority=".3" .../>
<region id="b" ... />
<region id="c" ... priority=".2" ...>
<region id="d" ... />
</videolayout>
Then the regions would be layered, from top to bottom, c,a,b,d.
Saleem & Sharratt Expires - August 2006 [Page 33]
Internet-draft Media Server Markup Language February 2006
(MSML)
Portions of regions that extend beyond the root window will be
cropped. For example, a layout specified as:
<videolayout>
<root size="CIF"/>
<region id="foo" left="50%" top="50%" size="2/3"/>
</videolayout>
would appear similar to:
+-----------+
| root |
|background |
| +-----+--
| | |//
| | foo |//
+-----+-----+//
|////////
Visual attributes are used to define aspects of the visual appearance
of individual regions. A border may be defined together with a title
and/or logo. Text and logos are displayed as images on top of the
region's video, below all regions with a lower priority. The visual
attributes are "title", "titletextcolor", "titlebackgroundcolor",
"bordercolor", "borderwidth", and "logo".
Visual attributes can also be defined for individual streams (Video
Stream Properties). When visual attributes are specified as part of
both a region and a stream, those associated with the stream MUST
take precedence. This allows streams that are chosen for display
automatically (Stream Selection) to have proper text and logos
displayed. The region visual attributes are displayed when no stream
is associated with the region.
Two other attributes associated with a region, "blank" and "freeze",
define the state of the video displayed in the region. When the blank
or freeze attribute is assigned the value "true", then the Media
Server MUST display the region either as a blank region, or the video
image frozen at the last received frame.
Open Issue: these attributes are specified for a region and not
allowed for streams because that appears to be the common use case.
Saleem & Sharratt Expires - August 2006 [Page 34]
Internet-draft Media Server Markup Language February 2006
(MSML)
Applying them to streams would allow only that stream to be affected
within a selector while other streams continue to display normally.
Except for personal mixing scenarios, the same effect can be achieved
by having the participant mute their own transmission to the media
server.
Attributes associated with each region are:
id: a name that can be used to refer to the region.
left: the position of the region from the left side of the root
window.
top: the position of the region from the top of the root
window.
relativesize: the size of the region expressed as a fraction of
the root window size.
priority: a number between 0 and 1 that is used to define the
precedence when rendering overlapping regions. A value of zero
disables the region.
title: text to be displayed as the title for the region
titletextcolor: the color of the text
titlebackgroundcolor: the color of the text background
bordercolor: the color of the region border
borderwidth: the width of the region border
logo: the URI of an image file to be displayed
freeze: a boolean value, with a default of false, that defines
whether the video image should be frozen at the currently
displayed frame
blank: a boolean value, with a default of false, that defines
whether the region should display black instead of the
associated video stream
9.7.3 <selector>
It is often desired that one of several video streams be
automatically selected to be displayed. The <selector> element is
used to define the selection criteria and its associated parameters.
Saleem & Sharratt Expires - August 2006 [Page 35]
Internet-draft Media Server Markup Language February 2006
(MSML)
The selection algorithm is specified by the "method" attribute.
Currently defined selection methods allow for voice activated
switching and to iterate sequentially through the set of associated
video streams.
The regions that will display the selected video stream are placed as
child elements of the <selector> element. Including regions within a
<selector> element does not affect their layout with respect to
regions not subject to the selection. For simple video conferences
that display the video directly in the root window, the <root>
element can be placed as a child of <selector>. Region elements MUST
NOT be used in this case.
For example, below is a common video layout that allows the video
stream from the currently active speaker to be displayed in the large
region ("1") at the top left of the layout while the streams from
five other participants are displayed in regions located at the
layout periphery.
+-------+---+
| | 2 |
| 1 +---+
| | 3 |
+---+---+---+
| 6 | 5 | 4 |
+---+---+---+
<videolayout type="text/msml-basic-layout">
<root size="CIF"/>
<selector id="switch" method="vas">
<region id="1" left="0" top="0" size="2/3"/>
</selector>
<region id="2" left="67%" top="0" size="1/3"/>
<region id="3" left="67%" top="33%" size="1/3">
<region id="4" left="67%" top="67%" size="1/3"/>
<region id="5" left="33%" top="67%" size="1/3"/>
<region id="6" left="0" top="67%" size="1/3"/>
</videolayout>
Saleem & Sharratt Expires - August 2006 [Page 36]
Internet-draft Media Server Markup Language February 2006
(MSML)
All selector methods must be defined so that they work if only a
single region is a child of the selector. Selector methods that
support more than one child region MUST specify how the method works
across multiple regions. Media server implementations MAY support
only a single region for methods that are defined to allow multiple
regions.
The selector or region for a participant's video is defined using the
"display" attribute of <stream> during a join operation. Specifying a
selector allows the stream to be displayed according to the criteria
defined by the selector method. Specifying a region supports
continuous presence display of participants. Some streams may be
joined with both a selector and a region. In this case, the value of
<blankothers> attribute defines whether the streams associated with a
continuous presence region should be blanked when the stream is
selected for display in one of the selector regions.
Attributes common to all selector methods are:
id: a name that can be used to refer to the selector.
method: the name of the method used to select the video stream.
status: specifies whether the selector is "active" or
"disabled".
blankothers: when "true", video streams that are also displayed
in continuous presence regions will have the continuous
presence regions blanked when the stream is displayed in a
selection region.
9.7.3.1 <vas> Voice Activate Switching
Voice activated switching (VAS) is used to display the video stream
that correlates with the participant who is currently speaking. It is
specified using a selector method value of "vas".
If the video stream associated with the active speaker is not
currently displayed in a selection region, then it replaces the video
in the region that is displaying the video of the speaker that was
least recently active. If the video of the active speaker is
currently displayed in a selection region, then there is no change to
any region. When VAS is applied to a single region, this has the
effect that the current speaker is displayed in that region.
Attributes associated with voice activated switching are:
Saleem & Sharratt Expires - August 2006 [Page 37]
Internet-draft Media Server Markup Language February 2006
(MSML)
si: switching interval is the minimum period of time that must
elapse before allowing the video to switch to the active
speaker.
speakersees: defines whether the active speaker sees the
"current" speaker (themselves) or the "previous" speaker.
9.8 <join>
<join> is used to create one or more streams between two independent
objects. Streams may be audio or video and may be bidirectional or
unidirectional. A bidirectional stream is implicitly composed of two
unidirectional streams that can be manipulated independently. The
streams to be established are specified by <stream> elements (section
<stream>) as the content of <join>.
Without any content, <join> by default establishes a bidirectional
audio stream. When only a stream of a single type has previously been
created between two objects, or when only a unidirectional stream
exists, <join> can be used to add a stream of another media type or
make the stream bidirectional by including the necessary <stream>
elements. Bidirectional streams are made unidirectional by using
<unjoin> (section <unjoin>) to remove the unidirectional stream for
the direction that is no longer required.
In addition to defining the media type and direction of streams,
<stream> elements are also used to establish the properties of
streams, such as gain, voice masking, or tone clamping of audio
streams, or labels and other visual characteristics of video streams.
Properties are often defined asymmetrically for a single direction of
a stream. Creating a bidirectional stream requires two <stream>
elements within the <join>, one for each direction, if one direction
is to have different properties from the other direction.
If a media server can provide services using both compressed or
uncompressed media, the MSML client may need to distinguish within
requests which format is to be used. When compressed streams are
created, both objects must use the same media format or an error
response (450) is generated.
attributes:
id1: an identifier of either a connection or conference.
Wildcards MUST NOT be used. Any other object class results in a
440 error.
Saleem & Sharratt Expires - August 2006 [Page 38]
Internet-draft Media Server Markup Language February 2006
(MSML)
id2: an identifier of either a connection or conference.
Wildcards MUST NOT be used. Any other object class results in a
440 error.
mark: a token which can be used to identify execution progress
in the case of errors. The value of the mark attribute from the
last successfully executed MSML element is returned in an error
response. Therefore the value of all mark attributes within an
MSML document SHOULD be unique.
For example, consider a call center coaching scenario where a
supervisor can listen to the conversation between an agent and a
customer, and provide hints to the agent, which are not heard by the
customer. One join establishes a stream between the agent and the
customer and another join establishes a stream between the agent and
the supervisor. A third join is used to establish a half-duplex
stream from the customer to the supervisor. The media server
automatically bridges the media streams from the customer and the
supervisor for the agent, and from the customer and the agent for the
supervisor.
Assuming the following connections, each with a single audio stream:
conn:supervisor
conn:agent
conn:customer
The following would create the media flows previously described:
<?xml version="1.0" encoding="UTF-8"?>
<msml version="1.1">
<join id1="conn:supervisor" id2="conn:agent"/>
<join id1="conn:agent" id2="conn:customer"/>
<join id1="conn:supervisor" id2="conn:customer">
<stream media="audio" dir="to-id1"/>
</join>
</msml>
The following example, shows joining a participant to a multimedia
conference. It assumes that the conference has a video presentation
Saleem & Sharratt Expires - August 2006 [Page 39]
Internet-draft Media Server Markup Language February 2006
(MSML)
region named "topright". The "display" attribute is explained in
section Video Stream Properties.
<?xml version="1.0" encoding="UTF-8"?>
<msml version="1.1">
<join id1="conn:hd83t5hf7g3" id2="conf:example">
<stream type="audio"/>
<stream type="video" dir="from-id1" display="topright"/>
<stream type="video" dir="to-id1"/>
</msml>
9.9 <modifystream>
Media streams can have different properties such as the gain for an
audio stream or a visual label for a video stream. These properties
are specified as the content of <stream> elements (section <stream>).
<modifystream> is used to change the properties of a stream by
including one or more <stream> elements that are to have their
properties changed.
Stream properties MUST be set as specified by the element <stream> as
a child element of <modifystream> element. Any properties not
included in the <stream> element when modifying a stream MUST remain
unchanged. Setting a property for only one direction of a
bidirectional stream MUST NOT affect the other direction. The
directionality of streams can be changed using issuing an <unjoin>
followed by a <join>. Any streams that exist between the two objects
that are not included within <modifystream> MUST NOT be affected.
attributes:
id1: an identifier of either a conference or a connection. The
instance name MUST NOT contain a wildcard if "id2" contains a
wildcard. Mandatory.
id2: an identifier of either a conference or a connection. The
instance name MUST NOT contain a wildcard if "id1" contains a
wildcard. Mandatory.
mark: a token which can be used to identify execution progress
in the case of errors. The value of the mark attribute from the
last successfully executed MSML element is returned in an error
response. Therefore the value of all mark attributes within an
MSML document are RECOMMENDED to be unique.
Saleem & Sharratt Expires - August 2006 [Page 40]
Internet-draft Media Server Markup Language February 2006
(MSML)
9.10 <unjoin>
Unjoin removes one or more media streams between two objects. In the
absence of any content in <stream> element, all media streams between
the objects MUST be removed. Individual streams may be removed by
specifying them using <stream> elements, while the unspecified
streams MUST NOT be removed. A bidirectional stream is changed to a
unidirectional stream by unjoining the direction that is no longer
required, using the <unjoin> element. Operator elements MUST NOT be
specified within <stream> elements when streams are being unjoined
using the <unjoin> element. Any specified stream operators MUST be
ignored.
<unjoin> and <join> may be used together to move a media stream, such
as from a main conference to a sidebar conference.
attributes:
id1: an identifier of either a conference or a connection. The
instance name MUST NOT contain a wildcard if "id2" contains a
wildcard. Mandatory.
id2: an identifier of either a conference or a connection. The
instance name MUST NOT contain a wildcard if "id1" contains a
wildcard. Mandatory.
mark: a token which can be used to identify execution progress
in the case of errors. The value of the mark attribute from the
last successfully executed MSML element is returned in an error
response. Therefore the value of all mark attributes within an
MSML document SHOULD be unique.
The following removes a participant from a conference and plays a
leave tone for the remaining participants in the conference.
<?xml version="1.0" encoding="UTF-8"?>
<msml version="1.1">
<unjoin id1="conn:jd73ht89sf489f" id2="conf:1"/>
<dialogstart target="conf:1" type="application/moml+xml">
<play>
<audio uri="file://leave_tone.wav"/>
</play>
</dialogstart>
</msml>
Saleem & Sharratt Expires - August 2006 [Page 41]
Internet-draft Media Server Markup Language February 2006
(MSML)
9.11 <monitor>
Monitor is a specialized unidirectional join that copies the media
that is destined for a connection object. One example of the use for
<monitor> may be quality monitoring within a conference. The media
stream may be removed using the <unjoin> element (see section
<unjoin>).
attributes:
id1: an identifier of the connection to be monitored. Any other
object class results in a 440 error. Wildcards MUST NOT be
used.
id2: an identifier of the object which is to receive the copy
of the media destined to id1. id2 may be a connection or a
conference. Any other object class results in a 440 error.
Wildcards MUST NOT be used.
compressed: "true" or "false". Specifies whether the join
should occur before or after compression. When "true", id2 must
be a connection using the same media format as id1 or an error
response (450) is generated. Default is "false.
mark: a token which can be used to identify execution progress
in the case of errors. The value of the mark attribute from the
last successfully executed MSML element is returned in an error
response. Therefore the value of all mark attributes within an
MSML document SHOULD be unique.
9.12 <stream>
Individual streams are specified using the <stream> element. They MAY
be included as a child element in any of the stream manipulation
elements <join>, <modifystream>, or <unjoin>.
The type of the stream is specified using a "media" attribute that
uses values corresponding to the top-level MIME media types as
defined in RFC 2046 [21]. This specification only addresses audio and
video media. Other specifications may define procedures for
additional types.
A bidirectional stream is identified when no direction attribute
"dir" is present. A unidirectional stream is identified when a
direction attribute is present. The "dir" attribute MUST have a value
of "from-id1" or "to-id1" depending on the required direction. These
Saleem & Sharratt Expires - August 2006 [Page 42]
Internet-draft Media Server Markup Language February 2006
(MSML)
values are relative to the identifier attributes of the parent
element.
The compressed attribute is used to distinguish the compressed nature
of the stream when necessary. It is implementation specific what is
used when the attribute is not present. Joining compressed streams
acts much like an RTP [15] relay.
The properties of the media streams are specified as the content of
<stream> elements when the element is used as a child of <join> or
<modifystream>. Stream elements MUST NOT have any content when they
are used as a child of <unjoin> to identify specific streams to
remove.
Some properties are defined within MSML as additional attributes or
child elements of <stream> that are media type specific. Ones for
audio streams and video streams are defined in the following two sub-
sections. Operators, viewed as properties of the media stream, MAY be
specified as child elements of the <stream> element.
attributes:
media: "audio" or video". Mandatory
dir: "from-id1" or "to-id1".
compressed: "true" or "false". Specifies whether the stream
uses compressed media. Default is implementation specific.
9.12.1 Audio Stream Properties
Audio mixes can be specified to only mix the N-loudest participants.
However there may be some "preferred" participants that are always
able to contribute. When audio streams are joined to a conference
that uses N-loudest audio mixing, preferred streams need to be
identified.
A preferred audio stream is identified using the "preferred"
attribute. The "preferred" attribute MAY be used for an audio stream
that is input to a conference and MUST NOT be used for other streams.
Additional attributes of the <stream> element for audio streams are:
preferred: a boolean value that defines whether the stream does
not contend for N-loudest mixing. A value of "true" means that
the stream MUST always be mixed while a value of "false" means
that the stream MAY contend for mixing into a conference when
N-loudest mixing is enabled. Default "false".
Saleem & Sharratt Expires - August 2006 [Page 43]
Internet-draft Media Server Markup Language February 2006
(MSML)
There are two elements that can be used to change the characteristics
of an audio stream as defined below.
9.12.1.1 <gain>
The <gain> element may be used to adjust the volume of an audio media
stream. It may be set to a specific gain amount, to automatically
adjust the gain to a desired target level, or to mute the stream.
Attributes of the <gain> element are:
amt: a specific gain to apply specified in dB or the string
"mute" indicating that the stream should be muted. This
attribute MUST NOT be used if "agc" is present.
agc: boolean indicating whether automatic gain control is to be
used. This attribute MUST NOT be used if "amt" is present.
tgtlvl: the desired target level for AGC specified in dBm0.
This attribute MUST be specified if "agc" is set to "true".
This attribute MUST NOT be specified if "agc" is not present.
maxgain: the maximum gain that AGC may apply. Maxgain is
specified in dB. This attribute MUST be used if "agc" is
present and MUST NOT be used when "agc" is not present.
9.12.1.2 <clamp>
The <clamp> element is used to filter tones and/or audio-band dtmf
from a media stream.
Attributes of the <clamp> element are:
dtmf: boolean indicating whether DTMF tones should be removed.
tone: boolean indicating whether other tones should be removed.
9.12.2 Video Stream Properties
Video mixes define a presentation that may have multiple regions,
such as a quad-split. Each region displays the video from one or more
participants. When video streams are joined to such a conference, the
region that will display the video needs to be specified as part of
the join operation.
The region that will display the video is specified using the
"display" attribute. The "display" attribute MUST be used for a video
stream that is input to a conference and MUST NOT be used for other
Saleem & Sharratt Expires - August 2006 [Page 44]
Internet-draft Media Server Markup Language February 2006
(MSML)
streams. The value of the attribute MUST identify a <region> (see
section <region>) or a <selector> (see section <selector>) that is
defined for the conference. A stream MUST NOT be directly joined to a
region that is defined within a selector. Changing the value of the
"display" attribute can be used to change where in a video
presentation layout a video stream is displayed.
Additional attributes of the <stream> element for video streams are:
display: the identifier of a video layout region or selector
that is to be used to display the video stream.
9.12.2.1 <visual>
Some regions of video conferences may display different streams
automatically, such as when voice activated switching is used.
Connections MAY also be joined directly without the use of video
mixing. In these cases, the <visual> element may be used to define
visual display properties for a stream.
The <visual> element MAY use any of the visual attributes defined for
regions (see section <region>). This allows the visual aspects of
regions within a <selector> to be tailored to the selected video
stream, or for streams that are directly joined to display a name or
logo.
10. MSML Dialog Packages
10.1 Overview
MSML Dialog Packages define an XML [4] language for composing complex
media objects from a vocabulary of simple media resource objects
called primitives. It is primarily a descriptive or declarative
language to describe media processing objects. MSML dialogs operate
on a single or multiple streams which are identified by the MSML
document outside the scope of the MSML dialog package.
MSML Dialogs are intended to be used in different environments. As
such, the language itself does not define how an MSML Dialog is used.
Each environment in which MSML Dialog is used must define how it is
used, the set of services provided and the mechanism for passing
information between the environment and MSML Dialog. The specific
mechanisms used to realize the interface between MSML Dialog and its
environment are platform specific.
MSML Dialog packages provide two models for access to media resources
and service creation building blocks. Both models MAY be used in
conjunction with each other in a complementary manner. The first
Saleem & Sharratt Expires - August 2006 [Page 45]
Internet-draft Media Server Markup Language February 2006
(MSML)
model (referred to as “Media Primitives and Composites”, part of the
mandatory MSML Dialog Base package) contains media primitives (such
as digit collection and announcements) and composite functions (such
as play and collect combined as a single operation). The second model
(referred to as “Media Groups”, part of the optional MSML Dialog
Group package) allows the ability to define complex customized
interactions, via event passing mechanisms, between media primitives,
if required.
MSML Dialog Core Package
Defines core framework over which all MSML dialog packages
operate.
MSML Dialog Base Package
Media Primitives
<dtmf> or <collect>
DTMF digit collection
<play>
Playing of Announcements
<dtmfgen>
Generation of DTMF digits
<record>
Media recording
Media Composites
<collect>
Supports play and collect operation.
Composite function with inclusion of play.
<record>
Supports play and record operation.
Composite function with inclusion of play.
MSML Dialog Group Package
<group>
Allows grouping of media primitives for parallel
execution, with an event exchange mechanism
between the media primitives to achieve
customized media operations. All the above media
primitive elements are accepted within the
group.
Following operations MUST be supported using elements described above
using either the MSML Dialog Base Package or MSML Dialog Group
Package.
Saleem & Sharratt Expires - August 2006 [Page 46]
Internet-draft Media Server Markup Language February 2006
(MSML)
Announcement only
<play>
Collection only
<dtmf> or <collect>
Recording only
<record>
Play and Collect
<collect>
<play/>
</collect>
Play and Record
<record>
<play/>
</record>
Additional MSML Dialog packages are:
O MSML Dialog Transform Package
O MSML Dialog Speech Package
O MSML Fax Detection Package
O MSML Fax Send/Receive Package
MSML Dialogs MAY be used to simply expose primitive media resource
objects but will be used more often to describe dialog operations and
media transformation objects which can be controlled via user
interaction.
MSML Dialogs do not contain any computation or flow control
constructs. There are no results automatically generated when media
operations complete. Results MUST be explicitly requested using a
<send> or <exit> element within the definition of the MSML Dialog.
10.2 Primitives
Primitives perform a single function on a media stream or multiple
streams such as generating audio/video, recognizing speech or DTMF,
or adjusting the gain. They may be composed so that primitives
execute concurrently. Primitives not composed for concurrent
execution MUST simply execute sequentially in the order they occur in
a MSML document. All concurrently executing primitives in the same
MSML object (defined in one MSML document) MAY interact with each
other through events (see MSML Dialog Group package).
Saleem & Sharratt Expires - August 2006 [Page 47]
Internet-draft Media Server Markup Language February 2006
(MSML)
Currently all primitives use audio media; primitives for text and
video will be defined in future versions of this specification.
Primitives can roughly be considered to fall into one of three
descriptive categories.
o recognizers have a media input but no output. They allow
different things within a media stream to be recognized or
detected and for events to be generated based upon received
media.
o transformers have one media input and output and may send and
receive events;
o sources and sinks generate or consume media. They have either a
media input or a media output but not both. They may receive
and generate events.
o composites combine underlying primitives to provide higher-
level user interaction, without the need for specific event
based exchange between the primitives. The composite elements
provide a simpler mechanism for more commonly used services,
such as play and collect or play and record.
Primitives may define different media processing behavior (states)
based upon the events which they receive. Primitives which support
different processing states must define their default starting state
and should support the "initial" attribute to allow that state to be
specified when the primitive is instantiated. All primitives must
support the "terminate" event class.
The following types of primitives are defined within this
specification:
Recognizers Transformers Source/Sink Composites
------------------------------------------------------
dtmf agc play collect
faxtone clamp record record
speech gain dtmfgen
vad gate faxsend
relay faxrcv
Primitives have shadow variables, similar to those within VoiceXML
[7], which are automatically assigned values when the primitives are
used. Upon initialization of an MSML Dialog context, all shadow
variables have the string value "undefined". Each primitive has its
own instance of shadow variables which are global in scope to the
entire MSML Dialog context.
Saleem & Sharratt Expires - August 2006 [Page 48]
Internet-draft Media Server Markup Language February 2006
(MSML)
Names SHOULD be assigned to individual primitives when more than one
primitive of the same type is used within one MSML document. Shadow
variables are overwritten if the primitive has not been named and is
instantiated a second time.
Shadow variables cannot be modified under user control. They may be
returned from the MSML Dialog context using the <send> element.
10.3 Events
Events provide the mechanism for primitives to interact with each
other and for a MSML context to interact with its external
environment. The external environment is defined by the way in which
a MSML context has been invoked. This will often be through MSML but
other languages and protocols such as SIP may also be used.
Every primitive and group conceptually implements their own event
queue. Events sent to them get placed into their associated queue.
Events are removed from their queues and processed in order.
Primitives within a group conceptually have their own thread of
execution. Due to the asynchronous nature of servicing events from
multiple queues, it cannot be assumed that several events sent in
sequence to different queues, will be processed in the order in which
they were sent. For example, if recognition of something led to
sending events to both a <play> and a <record> in that order, it is
possible that the <record> may process its event before the <play>.
Primitives each define the set of events which they support and the
behavior associated with their handling of each event. This allows
many types of behaviors to be defined. For example, VCR type controls
can be constructed by defining primitives which support events
corresponding to each control. Media recognition/detection can be
used to cause those events to be generated.
Alternatively, events can be originated elsewhere, such as from a
Control Agent, and simply received by the primitive implementing the
control. Examples of the use of events include adjusting volume
(gain) and pause and resume of both announcement playout and record
creation.
Primitives act on events based upon the longest match of an event
name. Event names are a period '.' delimited sequence of tokens. The
first token, or the root of the name, can be considered an event
class. Matching allows a standard meaning to be defined and then
extended based upon what triggers an event's generation. For example,
a record primitive has different behavior depending upon whether it
completed because a user stopped speaking or because it was
Saleem & Sharratt Expires - August 2006 [Page 49]
Internet-draft Media Server Markup Language February 2006
(MSML)
cancelled. The recording is retained in the first case but not the
second.
Longest match allows new recognizers to be created and used without
changing how existing primitives are defined. For example, a face
recognition capability could be created which generates a
terminate.frowning event when a user looks puzzled. Although no
primitive directly defines this event, it will still effect a generic
terminate action. Primitives which require specialized behavior based
upon frowning may be extended to support this. As well, the event can
still be exported from the MSML context without requiring that
primitives receiving the event understand facial expressions.
10.4 MSML Dialog Usage with SIP
MSML Dialogs MAY be used directly with SIP for dialog interactions
(e.g., IVR or fax). It can be initially invoked as part of the
"Prompt and Collect" service described in "Basic Network Media
Services with SIP" [9]. That defines service indicators for a small
number of well defined services using the user part of the SIP
Request-URI (R-URI).
The prompt and collect service uses "dialog" as the service
indicator. URI parameters further refine the specific IVR request.
This document defines an additional parameter "msml-param" for the
dialog service indicator as follows:
dialog-parameters = ";" ( dialog-param [ vxml-parameters ] )
| moml-param
dialog-param = "voicexml=" dialog-url
moml-param = "moml=" moml-url
There are no additional URI parameters when MSML is used as the
dialog language.
MSML Dialogs defines discrete IVR dialog commands. These commands MAY
be included directly in the body of the INVITE to the "dialog"
service indicator by using the "cid" [12] URL scheme. This scheme
identifies a message body part which in this case would contain the
MSML Dialog request. Note that a multipart message body, containing a
single part, MUST be present even if the INVITE does not contain an
SDP offer. Subsequent MSML Dialog requests are sent in the body of
SIP INFO messages as are all messages from a media server.
An example of SIP URI as described above is:
sip:dialog@mediaserver.example.net;\
moml=cid:14864099865376@appserver.example.net
Saleem & Sharratt Expires - August 2006 [Page 50]
Internet-draft Media Server Markup Language February 2006
(MSML)
The body part that contained the MSML Dialog referenced by the URL
would have a Content-Id header of:
Content-Id: <14864099865376@appserver.example.net>
The results of executing an <exit> or <disconnect>, or of executing a
<send> which has a "target" attribute value equal to "source", are
notified in SIP INFO messages using the <event> element from MSML
Core package. No messages are sent if execution completes normally
without executing one of these elements.
If there is an error during validation or execution, then a media
server MUST notify the error as described above and must include the
namelist items "moml.error.status" and "moml.error.description". The
values for these items are defined in section 11.
A restricted subset of MSML Dialogs can also be used with the
"Announcement" service defined in [9]. This service uses "annc" as
the service indicator and defines parameters that describe an
announcement. The "play=" parameter identifies the URL of a prompt or
a provisioned announcement sequence. The value of the "play="
parameter can refer to a MSML Dialog body part using a "cid" URL as
described above. That body part must only contain the <play>
primitive.
Using MSML Dialogs enhances the announcement service by allowing the
client to specify a sequence of audio segments rather than requiring
each sequence to be provisioned as well as support for video.
Moreover, MSML Dialogs define a standard set of variables in contrast
to [9] which defines a parameterization mechanism but does not
formally specify any semantics.
If a media server does not understand the "cid" scheme or does not
understand MSML Dialogs, it must respond with the SIP response code
"488 - not acceptable here". If the MSML Dialog body contains
elements other than the <play> primitive, or there are errors during
validation, a media server must respond with a SIP response code "400
- bad request". Finally, if there is a discrepancy between parameters
specified in the Request-URI and corresponding attributes defined in
the MSML Dialog body, the Request-URI parameters must be silently
ignored.
MSML Dialogs MUST NOT change the operation of the announcement
service from that defined in [9]. When the announcement completes, a
media server issues a SIP BYE request. The INFO method MUST NOT used
with the announcement service.
Saleem & Sharratt Expires - August 2006 [Page 51]
Internet-draft Media Server Markup Language February 2006
(MSML)
10.5 MSML Dialog Structure and Modularity
MSML is structured as a set of packages. Only the core and base
packages are required. The Dialog Core package, defines the framework
for MSML requests to a media server, without specific functionality.
It consists of the “primitive” abstraction, an abstract element for
control flow, the sequential execution model, and the <send> element.
That is, the MSML Dialog Core package allows for the execution of a
sequence of one or more media processing primitives with the ability
to notify events to the invocation environment.
Primitives are contained within the MSML Dialog Base package, which
defines the basic <play>, <record>, <dtmf>, <dtmfgen> and <collect>
elements. Another package, the MSML Dialog Transform package, defines
the simple half duplex filters. More advanced primitives are defined
in the speech and fax packages. The MSML speech package depends on
the MSML Dialog base package as it extends the capability of <play>
by adding synthesized speech. Finally, the group execution model,
which is currently the only element which changes the flow of control
is defined in a separate MSML Dialog Group package. All of these
packages are optional with the exception that MSML Dialog Core and
MSML Dialog Base packages MUST be implemented to provide the minimal
functionality.
10.6 MSML Dialog Core Package
The MSML Dialog Core package defines the structural framework and
abstractions for MSML Dialogs(via its schema). It also defines the
basic elements which are not part of the core primitive or control
abstractions. This package is dependent on the MSML Core package.
Events generated by MSML Dialogs, such as prompt completion, digits
collected, or dialog termination, etc, are communicated by the Media
Server via the MSML Core Package (see MSML Core Package <event>).
MSML Dialogs are executed independently from the MSML core context.
When an MSML Dialog is started, MSML allocates the dialog control
resources, and if successful, starts those resources executing. MSML
core execution then continues without waiting for the MSML dialog to
complete. This forking of MSML dialog invocation from the MSML core
context is done via the <dialogstart> element. Media streams are
created between the MSML dialog target and other internal media
server resources as part of dialog execution. Stream creation is
subject to the requirements defined in MSML Core package and media
streams as defined in MSML Conference Core package.
Saleem & Sharratt Expires - August 2006 [Page 52]
Internet-draft Media Server Markup Language February 2006
(MSML)
10.6.1 <dialogstart>
The <dialogstart> element is used to instantiate an MSML media dialog
on connections or conferences. The dialog is specified either inline
or by a URI [8]. Inline dialogs MUST be composed of any of the MSML
Dialog packages. MSML dialogs MAY be defined externally as VoiceXML
[7]. The MSML dialog description MUST NOT be inline if the src
attribute, containing a URI, is present.
The originator of the MSML dialog is notified using a
"msml.dialog.exit" event when the dialog completes. Any results
returned by the dialog when it exits are sent as a namelist to the
event.
The "msml.dialog.exit" event is also used when dialogs fail due to
errors encountered fetching external documents or errors that occur
within the dialog execution thread. In this case, a namelist
containing the items "dialog.exit.status" and
"dialog.exit.description" is returned with the event to inform the
client of the failure and the failure reason. The values of these
items are defined within this package and the MSML Core package.
Information from the failed dialog may be returned as additional
namelist items.
attributes:
target: an identifier of a connection or a conference which
will interact with the dialog. The identifier must not contain
wildcards. Mandatory.
src: the URL of the dialog description. MUST NOT be used if the
MSML dialog description is inline. Otherwise an error (422)
will result and MSML document execution will stop.
type: a MIME type which identifies the type of language used to
describe the dialog. application/moml+xml and
application/vxml+xml are used to identify MSML Dialogs and
VoiceXML [7] respectively.
name: an instance name for the dialog. If the attribute is not
present, the media server will assign an identifier to the
dialog. If the attribute is present but the name is already
associated with the target, an error (431) will result and MSML
document execution will stop. Any results that a dialog
generates will be correlated to its identifier.
mark: a token which can be used to identify execution progress
in the case of errors. The value of the mark attribute from the
Saleem & Sharratt Expires - August 2006 [Page 53]
Internet-draft Media Server Markup Language February 2006
(MSML)
last successfully executed MSML element is returned in an error
response. Therefore the value of all "mark" attributes within
an MSML document should be unique.
The following sections show examples of initiating an external MSML
dialog, an in-line embedded MSML dialog, and an MSML initiated
VoiceXML dialog.
The following example starts a MSML dialog on a connection.
<?xml version="1.0" encoding="UTF-8"?>
<msml version="1.1">
<dialogstart target="conn:abcd1234"
type="application/moml+xml"
name="sample"
src="http://server.example.com/scripts/foo.moml"/>
</msml>
The following example starts an in-line embedded MSML dialog on a
connection.
<?xml version="1.0" encoding="UTF-8"?>
<msml version="1.1">
<dialogstart target=”conn:abcd1234” name=”sample”>
<play>
<audio uri="file://clip1.wav"/>
<audio uri="http://host1/clip2.wav"/>
<tts uri="http://host2/text.ssml"/>
<var type="date" subtype="mdy" value="20030601"/>
</play>
<send target="source"
event="done"
namelist="play.amt play.end"/>
</dialogstart>
</msml>
The following example starts a VoiceXML dialog on a connection.
Saleem & Sharratt Expires - August 2006 [Page 54]
Internet-draft Media Server Markup Language February 2006
(MSML)
<?xml version="1.0" encoding="UTF-8"?>
<msml version="1.1">
<dialogstart target="conn:abcd1234"
type="application/vxml+xml"
name="sample"
src="http://server.example.com/scripts/foo.vxml"/>
</msml>
If this dialog fails once its execution thread had begun, for example
the fetch of the VoiceXML document failed, an example of the event
which would be returned would be:
<?xml version="1.0" encoding="UTF-8"?>
<event name="msml.dialog.exit"
id="conn:abcd1234/dialog:sample">
<name>dialog.exit.status</name>
<value>423</value>
<name>dialog.exit.description</name>
<value>External document fetch error</value>
</event>
10.6.2 <dialogend>
Dialog end is used to terminate a MSML dialog created through
<dialogstart> before it completes of its own accord. The operation of
<dialogend> depends on the dialog language being used by the
executing context. When that context is VoiceXML, a
"connection.disconnected" event will be thrown to the VoiceXML
application. When that context is MSML Dialog, a "terminate" event
will be sent to the MSML core context.
<dialogend> allows the executing dialog the opportunity to gracefully
complete before generating a "msml.dialog.exit" event. Dialog results
may be returned and will be contained as a namelist to that event.
attributes:
id: the identifier of a dialog. Mandatory.
Saleem & Sharratt Expires - August 2006 [Page 55]
Internet-draft Media Server Markup Language February 2006
(MSML)
mark: a token which can be used to identify execution progress
in the case of errors. The value of the mark attribute from the
last successfully executed MSML Dialog element is returned in
an error response. Therefore the value of all "mark" attributes
within an MSML document should be unique.
For example, if the dialog from the previous example was still
executing, the following would terminate the dialog and generate a
"msml.dialog.exit" event.
<?xml version="1.0" encoding="UTF-8"?>
<msml version="1.1">
<dialogend id="conn:abcd1234/dialog:sample"/>
</msml>
10.6.3 <send>
Sends an event and optional namelist to the recipient identified by
the target attribute. Event names are defined by the recipient. In
the case where the recipient is an MSML Dialog group or primitive,
the events are defined within this document. Other recipients MAY use
names that are suitable for their environment.
The "target" attribute specifies the recipient of the event.
Recipients MAY be other MSML Dialog primitives or groups executing
within the object, the object itself, or the environment which
invoked the MSML Dialog. Sending events to media primitives or groups
is supported by the MSML Dialog Group package. Any target which is
unknown within the object is assumed to be destined to the external
environment. By convention, the string "source" SHOULD used to
address that environment but any target name distinct from the MSML
Dialog namespace MAY be used.
Attributes:
event: the name of an event.
target: the recipient of the event. The recipient MUST be a
MSML Dialog primitive, the currently executing group, or the
MSML Dialog environment. A primitive is specified by a
primitive type, optionally appended by a period '.' followed by
the identifier of a primitive. Identifiers are only needed when
more than one primitive of the same type exists in the object.
The executing group is specified using the token "group". The
environment is specified using the token "source", optionally
Saleem & Sharratt Expires - August 2006 [Page 56]
Internet-draft Media Server Markup Language February 2006
(MSML)
appended by a period '.' followed by any environment specific
target.
namelist: a list of zero or more shadow variables which are
included with the event.
10.6.4 <exit>
Exit causes execution of the MSML Dialog to terminate.
Attributes:
namelist: a list of one or more shadow variables which MAY
optionally be sent to the context which invoked the MSML Dialog
object.
10.6.5 <disconnect>
Disconnect is similar to <exit> but has the additional semantics of
indicating to the context which invoked the MSML Dialog, that it
should disconnect from a media server, the media stream associated
with the object. The method of disconnection depends upon how the
media stream was initially established. If SIP was used, a
<disconnect> would cause a media server to issue a BYE request. The
request would be sent for the SIP dialog associated with media
session on which the MSML Dialog was operating.
Attributes:
namelist: a list of one or more shadow variables which MAY
optionally be sent to the context which invoked the MSML Dialog
object.
10.7 MSML Dialog Base Package
The MSML Dialog Base package defines a required set of base
functionality for Media Server. It support individual media
primitives, such as playing an announcement or collection digits, as
well as composite operations such as play and collect. When this
package is used in conjunction with MSML Dialog Group package the
event based mechanism is used to control primitives. This package may
also be used in conjunction with MSML Speech package to extend the
functionality of prompts to include TTS and user input collection to
include ASR.
In the following sections, subsections of a primitive define child
elements of that primitive and are not themselves considered
primitives. They do not receive events or populate shadow variables.
Saleem & Sharratt Expires - August 2006 [Page 57]
Internet-draft Media Server Markup Language February 2006
(MSML)
10.7.1 <play>
Play is used to generate an audio or video stream. It MUST play in
sequence the media created by the child media elements <audio>,
<video>, <media>, <tts>, and <var>. When the play stops, either
because the terminate event is received or all media generation has
completed, the <playexit> element, if present, is executed. At least
one media generation element must be present.
Play supports two states; generate and suspend. Media generation
occurs in the generate state and is suspended in the suspend state.
Once in the suspend state, media generation continues upon receiving
the generate event. The default initial state is generate.
Audio MAY be generated in different languages by specifying the
xml:lang attribute for <play> and/or the child elements of <play>.
The language is inherited by the child elements but each child MAY
specify its own language. Except for physical audio clips, it is an
error if a language is specified but the media server can not render
the audio in the requested language.
Attributes:
id: an optional identifier which may be referenced elsewhere
for sending events to the play primitive.
interval: specifies the delay between stopping one iteration
and beginning another. The attribute has no effect if
iterations is not also specified. Default is no interval.
iterate: specifies the number of times the media specified by
the child media elements should be played. Each iteration is a
complete play of each of the child media elements in document
order. Defaults to once '1'.
initial: defines the initial state for the play element.
Default is "generate".
maxtime: defines the maximum allowed time for the <play> to
complete.
barge: defines whether or not audio announcements MAY be
interrupted by DTMF detection during play-out. The DTMF digit
barging the announcement is stored in the digit buffer. Valid
values for barge are “true” or “false”, and the attribute is
mandatory.
Saleem & Sharratt Expires - August 2006 [Page 58]
Internet-draft Media Server Markup Language February 2006
(MSML)
cleardb: defines whether the digit buffer is cleared or not,
prior to starting the announcement. Valid values for cleardb
are “true” or “false”, and the attribute is mandatory.
offset: defines an offset, measured in units of time, where the
<play> is to begin media generation. Offset is only valid when
all child media elements are <audio>.
skip: an amount, expressed in time, which will be used to skip
through the media when "forward" and "backward" events are
received. Default is 3s (three seconds).
xml:lang: specifies the language to use for content which can
be rendered in different languages.
Events:
Following describes input events to the media primitive object.
The MSML Dialog Group package allows an event exchange
mechanism between primitives.
pause: causes the play to enter the suspend state.
resume: causes play to enter the generate state.
forward: skips forward through the media. Only has effect when
all child media elements are <audio>.
backward: skips backward through the media. Only has effect
when all child media elements are <audio>.
restart: skips to the beginning of the media. Only has effect
when all child media elements are <audio>.
toggle-state: causes the suspend / generate state to toggle.
terminate: terminates the play and assigns values to the shadow
variables.
Shadow Variables:
play.amt: identifies the length of time for which media was
generated before the play was stopped. This does not include
time which may have elapsed while the play was in the suspend
state.
Saleem & Sharratt Expires - August 2006 [Page 59]
Internet-draft Media Server Markup Language February 2006
(MSML)
play.end: contains the event which caused the play to stop.
When the play stops because all media generation has completed,
end is assigned the value "play.complete".
Note: Attributes barge and cleardb provide a simplified mechanism for
controlling play operations with implicit DTMF without the use of
<group> and event exchange mechanism. When using the <play> element
within the group framework and barge is specified, detection of barge
condition generates an implicit terminate event to the play
primitive.
Following sections describe the child elements of <play>.
10.7.1.1 <audio>
Identifies pre-recorded audio to play. Local URI references may
resolve to a single physical audio clip, a logical clip, or a
provisioned sequence of clips (physical or logical). A logical clip
is one which can be rendered differently based on the language
attribute. Logical clips are provisioned for each of the languages
that a media server supports. Remote URI references are resolved
according to the capabilities of the remote server.
Attributes:
uri: Identifies the location of the audio to be played. The
file and http schemes are supported.
format: defines the encoding and file type of the audio
resource. The format attribute is defined as a string type of
form “audio/<filetype>;codecs=<codec>”. The keyword ‘audio’
identifies an audio content. The codecs field identifies the
audio file’s codec to be used for decoding the audio content.
If format attribute is not specified, the filetype MUST be
determined from the URI and the codec information MUST be
determined from the media resource.
audiosamplerate: Identifies audio sample rate in kHz. If not
specified, the sample rate SHOULD be determined from the media
resource.
audiosamplesize: Identifies audio sample size in bits. If not
specified, the sample size SHOULD be determined from the media
resource.
iterate: specifies the number of times the audio is to be
played. Defaults to once '1'.
Saleem & Sharratt Expires - August 2006 [Page 60]
Internet-draft Media Server Markup Language February 2006
(MSML)
xml:lang: specifies the language to use when the URI identifies
a logical clip, either directly, or as part of a sequence.
10.7.1.2 <video>
Identifies pre-recorded multimedia to play. Contents identified by
the URI attribute may contain audio only, video only, or both audio
and video. Media Server SHOULD attempt to play both audio and video
from the identified URI, if both are available in the content.
Attributes:
uri: Identifies the location of the video or multimedia to be
played. The file and http schemes are supported.
format: defines the encoding and file type of the video or
multimedia resource. The format attribute is defined as a
string type of form
“video/<filetype>;codecs=<codecx>,<codecy>”. The keyword
‘video’ identifies video only media or media containing audio
and video. The “codecs” field identifies the audio and/or video
codecs to be used for decoding the file content, where the
order of the codec values is not significant. In the event of
audio and video content, using ‘video’ keyword, the
codecs=<codecx>,<codecy> field MAY be used to identify the
audio codec and the video codec. If not specified, the codec
information SHOULD be determined from the media file.
audiosamplerate: Identifies audio sample rate in kHz. If not
specified, the sample rate SHOULD be determined from the media
file.
audiosamplesize: Identifies audio sample size in bits. If not
specified, the sample size SHOULD be determined from the media
file.
codecconfig: Identifies an optional special instruction string
for codec configuration. Default is to send no special
configuration string to the codec.
profile: Identifies a video profile name specific to the codec.
If not specified, default video profile of the codec SHOULD be
selected.
level: Identifies a video profile level to the codec. Default
is to send no profile information to the codec and allow the
codec to select an internal default.
Saleem & Sharratt Expires - August 2006 [Page 61]
Internet-draft Media Server Markup Language February 2006
(MSML)
imagewidth: Identifies the width of video image in pixels.
Default is to use image width information from media file.
imageheight: Identifies the height of video image in pixels.
Default is to use image height information from media file.
maxbitrate: Identifies the bitrate of the video signal in kbps.
Default is to use maximum bitrate information from the media
file.
framerate: Identifies the video frame rate in frames per
second. Default is to use frame rate information from the media
file.
iterate: specifies the number of times the audio is to be
played. Defaults to once '1'.
10.7.1.3 <media>
Identifies multimedia content for play. All content of <media>
element MUST start to play concurrently. This element may be used to
generate a multi-media stream from two independent media resources,
one identifying audio and the other identifying video.
The <media> element MUST contain at least one child element. Valid
child elements of <media> are <audio> and <video>, as described
earlier. <media> element MUST contain at most one <audio> element or
at most one <video> element.
10.7.1.4 <var>
Specifies the generation of audio from a variable using prerecorded
audio segments. A variable represents a semantic concept (such as
date or number) and dynamically produces the appropriate speech.
Prerecorded audio allows an application vendor or service provider to
choose the exact voice for their audio and therefore completely
control the "sound and feel" of the service provided to end users. It
provides very high audio quality and allows the variables to blend
seamlessly into the surrounding audio segments.
Text to speech (TTS) using SSML may also be used to render variables,
but may not provide as good quality, or allow as complete control of
the "sound and feel" or user experience. TTS is normally used for
reading text such as emails and for very large vocabularies such as
stock names. TTS results in a very clear difference between the
variables and the surrounding audio segments. (See MSML Dialog Speech
package).
Saleem & Sharratt Expires - August 2006 [Page 62]
Internet-draft Media Server Markup Language February 2006
(MSML)
Attributes:
type: specifies the type of variable. Mandatory. Variable type
must be one of "date", "digits", "duration", "month", "money",
"number", "silence", "time", or "weekday".
subtype: specifies an optional clarification of type. Specific
values depend upon the type.
value: text which should be rendered appropriate to the type
and subtype attributes.
xml:lang: specifies the language to use when rendering the
variable.
10.7.1.5 <playexit>
The <playexit> element MUST be invoked when generation of all content
of the <play> has come to completion. The contents of this element
MAY be used to send events.
Attributes:
none
10.7.2 <dtmfgen>
DTMF generator originates one or more DTMF digits in sequence.
Attributes:
id: an optional identifier which may be referenced elsewhere
for sending events to the dtmfgen primitive.
digits: A string of characters from the alphabet "0-9a-d#*"
which correspond to a sequence of DTMF tones. Mandatory.
level: used to define the power level for which the tones will
be generated. Expressed in dBm0 in a range of 0 to -96 dBm0.
Larger negative values express lower power levels. Note that
values lower than -55 dBm0 will be rejected by most receivers
(TR-TSY-000181, ITU-T Q.24A). Default is -6 dBm0.
dur: the duration in milliseconds for which each tone should be
generated. Implementations may round the value if they only
support discrete durations. Default 100 ms.
Saleem & Sharratt Expires - August 2006 [Page 63]
Internet-draft Media Server Markup Language February 2006
(MSML)
interval: the duration in milliseconds of a silence interval
following each generated tone. Implementations may round the
value if they only support discrete durations. Default 100 ms.
Events:
terminate: terminates DTMF generation and assigns values to the
shadow variables.
Shadow Variables:
dtmfgen.end: contains the event which caused DTMF generation to
stop.
The following sections describe the child elements of <dtmfgen>.
10.7.2.1 <dtmfgenexit>
The <dtmfgenexit> element MUST be invoked when the DTMF generation
operation completes or is terminated as a result of receiving the
terminate event. The <dtmfgenexit> element MAY be used to send events
when the recording has completed.
Attributes:
none
10.7.3 <record>
Record creates a recording. Similar to play, <record> supports two
states; create and suspend. Received media becomes part of the
recording when <record> is in the create state and is discarded when
it is in the suspend state.
Recording MUST be terminated when a terminate event is received or
when a nospeech event is received and no audio has yet been recorded.
<record> differentiates different types of terminate events.
An optional <play> element MAY be specified as a child element of
<record>. This mechanism provides a complete play-record operation,
where the prompt(s) specified within the <play> element are played in
advance of start of recording.
Note: Attributes prespeech, postspeech, and termkey provide a
simplified mechanism for controlling record operations using implicit
DTMF and VAD, without the use of <group> and event exchange
mechanism.
Saleem & Sharratt Expires - August 2006 [Page 64]
Internet-draft Media Server Markup Language February 2006
(MSML)
Attributes:
id: an optional identifier which may be referenced elsewhere
for sending events to the record primitive.
append: a boolean which defines whether the recording is
allowed to be appended to an existing file if dest already
exists. Default is "false". The attribute is ignored if the
scheme is http.
dest: the destination for the recording, which will contain
either audio only, video only, or both audio and video
depending on the stream(s) being recorded. Recording MAY be
either local or external based upon the attribute value. File
and http schemes are supported.
audiodest: the destination for the audio only recording.
Recording MAY be either local or external based upon the
attribute value. All combinations of dest, audiodest, and
videodest are valid. File and http schemes are supported.
videodest: the destination for the video only recording.
Recording MAY be either local or external based upon the
attribute value. All combinations of dest, audiodest, and
videodest are valid. File and http schemes are supported.
format: defines the encoding and file type of the recording.
The format attribute is defined as a string type of form
“audio|video/filetype;codecs=x,y”. The keyword ‘audio’
identifies an audio only recording, while the keyword ‘video’
identifies video only recording or an audio plus video
recording. The codecs field identifies the audio and/or video
codecs to be used for the recording, where the order of the
codec values is not significant. In the event of audio and
video recording, using ‘video’ keyword, the codecs=x,y field
MAY be used to identify the audio codec and the video codec.
codecconfig: Identifies an optional special instruction string
for codec configuration. Default is to send no special
configuration string to the codec.
audiosamplerate: Identifies audio sample rate in kHz. If not
specified, the sample rate SHOULD be determined from the media
source.
audiosamplesize: Identifies audio sample size in bits. If not
specified, the sample size SHOULD be determined from the media
source.
Saleem & Sharratt Expires - August 2006 [Page 65]
Internet-draft Media Server Markup Language February 2006
(MSML)
profile: Identifies a video profile name specific to the codec.
If not specified, default video profile of the codec SHOULD be
selected for the recording.
level: Identifies a video profile level to the codec. Default
is to send no profile information to the codec and allow the
codec to select an internal default.
imagewidth: Identifies the width of video image in pixels.
Default is to use image width information from the media
source.
imageheight: Identifies the height of video image in pixels.
Default is to use image height information from the media
source.
maxbitrate: Identifies the bitrate of the video signal in kbps.
Default is to use maximum bitrate information from the media
source.
framerate: Identifies the video frame rate in frames per
second. Default is to use frame rate information from the media
source.
initial: defines the initial state for the record element.
Default is "create", which starts the recording as soon as the
<record> element is executed. The “initial” attribute is
applicable only when <record> is used within the <group>
structure.
maxtime: defines the maximum length of the recording in units
of time.
prespeech: defines a timer value, in seconds, for detection of
absence of audio energy at the start of the record operation.
If no audio energy is detection for the amount of time
specified by prespeech, the recording is terminated. Default is
“0s”, which does not activate the prespeech timer.
postspeech: defines a timer value, in seconds, for detection of
absence of audio energy while the recoding is in progress.
During an in progress recording, if absence of audio energy is
detected as specified by the postspeech timer, the recording is
terminated. Default is “0s”, which disables the ability to
terminate a recording due to postspeech silence.
termkey: defines a single DTMF key which when detection
terminates the recording. Absence of this attribute prevents
Saleem & Sharratt Expires - August 2006 [Page 66]
Internet-draft Media Server Markup Language February 2006
(MSML)
the recording from being terminated due to detection of DTMF
digits. When termkey is specified, the detected DTMF digit
terminates the recording and the DTMF digit is not entered in
the digit buffer.
Events:
Following describes input events to the media primitive object.
The MSML Dialog Group package allows an event exchange
mechanism between primitives.
pause: causes the record to enter the suspend state. Received
media is discarded.
resume: causes record to resume if it was suspended. It has no
effect otherwise.
toggle-state: causes the suspend / create state to toggle.
terminate: terminates the recording and assigns values to the
shadow variables.
terminate.cancelled: terminates the recording and assigns
values to the shadow variables. If the dest attribute used the
file scheme, the local recording is deleted. Applications are
responsible for removing external files created using the http
scheme.
terminate.finalsilence: terminates the recording and assigns
values to the shadow variables. If the dest attribute used the
file scheme, the final silence is removed from the recording.
nospeech: terminates the recording and assigns values to the
shadow variables if it is received and no recording has yet
been created. The "nospeech" event is ignored if audio has
already been recorded.
Shadow Variables:
record.len: the actual length of the recording measured in
units of time. This does not include time which may have
elapsed while the record was in the suspend state.
record.end: contains the event which caused the record to
terminate. When the record terminates because maxtime is
exceeded, end is assigned the value
"record.complete.maxlength".
Saleem & Sharratt Expires - August 2006 [Page 67]
Internet-draft Media Server Markup Language February 2006
(MSML)
Record termination due to prespeech silence, results in
assigned value of “record.failed.prespeech”
Record termination due to postspeech silence, results in
assigned value of “record.complete.postspeech”
Record termination due to DTMF detection, results in assigned
value of “record.complete.termkey”
The following sections describe the child elements of <record>.
10.7.3.1 <play>
The optional <play> element as a child element of <record> allows a
prompt to be played prior to start of recording. The record operation
starts at the end of the play sequence or if the play is barged by
DTMF, assuming that barge=true is specified for <play>. For a
complete description, refer to <play> element.
10.7.3.2 <recordexit>
The <recordexit> element MUST be invoked when the record operation
completes or when the recording is terminated as a result of
receiving the terminate event. The <recordexit> element MAY be used
to send events when the recording has completed.
Attributes:
none
10.7.4 <dtmf> or <collect>
DTMF input fulfils several roles within MSML Dialogs. It is used to
trigger events which will affect the media processing operation of
other primitives. It is also used to collect DTMF digits from a media
stream which are to be reported back to the user of MSML Dialog.
Often DTMF detection is used for both purposes. Barge is the most
common example, where a prompt is stopped based upon DTMF input but
more digits may remain to be collected.
DTMF detection supports multiple simultaneous recognition patterns.
Different patterns can be used to trigger sending different events in
order to implement DTMF controls. Alternatively one pattern may be
used to represent a collection and another pattern, a substring of
the first, used as a barge indication.
An optional <play> element MAY be specified as a child element of
<dtmf> or <collect>. This mechanism provides a complete play-collect
Saleem & Sharratt Expires - August 2006 [Page 68]
Internet-draft Media Server Markup Language February 2006
(MSML)
operation, where the prompt(s) specified within the <play> element
are played in advance of DTMF digit collection.
Note that all patterns share the same digit collection buffer, inter-
digit timing, a single <nomatch> element, and a single <noinput>
element. As such, multiple patterns may not be suitable to support
simultaneous collections for different purposes. When this is
required, separate <dtmf> elements should be used instead.
<dtmf> terminates if any of the <pattern>, <noinput>, or <nomatch>
elements are matched the maximum number of times that they are
allowed. The number of times they may match may be specified as an
attribute of <dtmf> or of the individual child elements.
Element identifier <dtmf> is equivalent to <collect>. However,
<collect> is the preferred name. MSML clients SHOULD use <collect>,
while MSML servers SHOULD support both.
Attributes:
id: an optional identifier which may be referenced elsewhere
for sending events to this primitive.
cleardb: a boolean indication of whether the buffer for digit
collection should be cleared of any collected digits when the
element is instantiated. If set to false, any digits currently
in the buffer MUST be immediately compared against the pattern
elements.
fdt: defines the first-digit timer value. The first-digit timer
is started when DTMF detection is initially invoked. If no DTMF
digits are detected during this initial interval, the <noinput>
element MUST be invoked.
idt: defines the inter-digit timer to be used when digits are
being collected. When specified, the timers is started when the
first digit is detected and restarted on each subsequent digit.
Timer expiration is applied to all patterns. After that, if any
patterns remain active and a nomatch element is specified, the
nomatch is executed and DTMF input MUST terminate. The idt
attribute should only be used when digit collection is being
performed. No default.
starttimer: boolean value which defines whether the first digit
timer (fdt) is started initially. When set to false, the
starttimer event must be received for it to start. Default
false.
Saleem & Sharratt Expires - August 2006 [Page 69]
Internet-draft Media Server Markup Language February 2006
(MSML)
iterate: specifies the number of times the <pattern>,
<noinput>, and <nomatch> elements may be executed unless those
elements specify differently. The value "forever" MAY be used
to indicate that these may be executed any number of times.
Default is once '1'.
Events:
Following describes input events to the media primitive object.
The MSML Dialog Group package allows an event exchange
mechanism between primitives.
starttimer: starts the first digit timer (fdt) if it has not
already been started. Has no effect otherwise.
terminate: terminates the DTMF input and assigns values to the
shadow variables.
Shadow Variables:
dtmf.digits: the string of DTMF digits which have been received
(the contents of the digit buffer).
dtmf.len: the number of digits in the digit buffer.
dtmf.last: the last digit in the digit buffer.
dtmf.end: contains the event which caused the <dtmf> to
terminate or is assigned one of "dtmf.match", "dtmf.noinput",
or "dtmf.nomatch" depending upon which of the corresponding
elements reached its maximum.
The following sections describe the child elements of <dtmf> or
<collect>.
10.7.4.1 <play>
The optional <play> element as a child element of <dtmf> or <collect>
allows a prompt to be played prior to DTMF digit collection. DTMF
digit collection starts at the end of the play sequence or if the
play is barged by DTMF, assuming that barge=true is specified for
<play>. For a complete description, refer to <play> element.
10.7.4.2 <pattern>
The pattern element describes one or more DTMF digits that are to be
recognized. When the pattern is matched, the child elements MUST be
executed.
Saleem & Sharratt Expires - August 2006 [Page 70]
Internet-draft Media Server Markup Language February 2006
(MSML)
Attributes:
digits: The digit pattern which should be matched.
format: an enumerated value which defines the format used to
express the digit pattern. The format may be "mgcp" or "megaco"
for patterns expressed as digit map from those specifications,
or as one of the simple built-in formats defined within this
specification. Currently, a single built-in format
"moml+digits" is defined which allows a match based on either
one or more specific digits, or based upon a specific length
specification with an optional return key. "moml+digits" is the
default.
iterate: specifies the number of times the <pattern> may be
matched. The value "forever" may be used to indicate that
<pattern> may be matched any number of times. This value
overrides any specified in <dtmf>. Default is once '1'.
10.7.4.3 <detect>
The contents of the <detect> element MUST be executed whenever any
DTMF is first detected. It MUST be matched at most once.
Attributes:
none
10.7.4.4 <noinput>
The <noinput> element is used when DTMF is being collected. Children
of the <noinput> element MUST be executed when DTMF has not been
detected and the first digit timeout occurs.
Attributes:
iterate: specifies the number of times the <noinput> may be
triggered. The value "forever" may be used to indicate that
<noinput> may be triggered any number of times. This value
overrides any specified in <dtmf>. Default is once '1'.
10.7.4.5 <nomatch>
The <nomatch> element is used when DTMF is being collected. Children
of the <nomatch> element MUST be executed when it is determined that
none of the individual patterns can be matched.
Attributes:
Saleem & Sharratt Expires - August 2006 [Page 71]
Internet-draft Media Server Markup Language February 2006
(MSML)
iterate: specifies the number of times the <nomatch> may be
triggered. The value "forever" may be used to indicate that
<nomatch> may be triggered any number of times. This value
overrides any specified in <dtmf>. Default is once '1'.
10.7.4.6 <dtmfexit>
The <dtmfexit> element MUST be invoked when the dtmf input completes
because one of <pattern>, <noinput>, or <nomatch> occurred its
maximum number of times.
Attributes:
None
10.7.5 <moml>
The root element <moml> MUST be used when the document is a stand-
alone MSML Dialog, where the invoking application media type
indicates ‘application/moml+xml’. Additionally, for backwards
compatibility, the <moml> element MUST be used within <dialogstart>
which contains an in-line embedded MSML dialog.
Valid contents of <moml> are all elements described within this MSML
Dialog Base package.
Attributes:
version: "1.0" Mandatory.
id: an identifier unique to this object. Events returned from
MSML dialog (the "target" attribute of a <send> is equal to
"source") will be correlated with this identifier. Mandatory.
Events:
terminate: terminates the MOML context. A terminate event gets
sent to the currently executing <group> or primitive.
10.8 MSML Dialog Group Package
The group package defines a single control flow construct that
specifies concurrent execution. Primitives are composed for
concurrent execution by placing them within a <group> element. Groups
define how media flows between multiple concurrently executing
primitives. They have one or more inputs and one or more outputs. A
Saleem & Sharratt Expires - August 2006 [Page 72]
Internet-draft Media Server Markup Language February 2006
(MSML)
<group> represents the declaration of a complex media processing
operation. The event interaction between primitives (see the
following sub-section) is defined within the context of one or more
groups. However groups themselves do not scope events, they simply
define that primitives are concurrently executing and a primitive
must be executing in order to receive an event.
Placing primitives within a group structure is an optional feature of
this specification. It allows for complex services to created using
the event exchange mechanism between the primitives. For simpler
services, such as play/collect or play/record, the use of group
mechanism is not necessary. MSML Dialog Group package is dependent on
the MSML Dialog Base package.
Groups may also be used to describe media objects which transform a
media stream while optionally allowing application or user control of
the transformation. For example a gain control could be defined which
responds to user speech or DTMF input. In this case a recognition
primitive would send events to a gain control primitive.
Groups have one attribute which defines the media flow within them.
They also have a dimension which defines how many media inputs and
outputs they have. Currently dimensions of 1 and 2 are supported
based upon the group topology. These correspond to a group with one
input and one output and a group with two inputs and two outputs.
Media flow to and from the primitives within the group is based upon
a topology attribute of the <group> element. This differs from a
similar mechanism in Media Policy Manipulation in the Conference
Policy Control Protocol [3] which explicitly defined connections. The
topology attribute defines a topology schema and implies the group
dimension.
There are several common ways in which primitives are often connected
together. A schema provides a convenient template which can be
applied to multiple primitives without having to define all of the
individual media relationships. The following two schemas are
initially defined for 1 dimensional groups:
o parallel: specifies that media sent to the group is sent to every
primitive which has an input. The group bridges the output from every
primitive which has an output into a single common group output;
o serial: specifies that the first primitive listed in the group
receives the media sent to the group. Its output is to be connected
to the input of the next primitive defined within the group and so on
until the last primitive within the group which becomes the group
output.
Saleem & Sharratt Expires - August 2006 [Page 73]
Internet-draft Media Server Markup Language February 2006
(MSML)
Groups with these topologies are shown in the two diagrams below. The
group on the left has a parallel topology and that on the right has a
serial topology.
/-> P1 --\
/ \
G(in) +---> P2 ----> G(out) G(in) --> P1 --> P2 --> P3 --> G(out)
\ /
\-> P3 --/
More complex media flows MAY be created by nesting groups of serial
and parallel topologies within each other. For example, the diagram
below has a group with a serial topology nested within a star
topology.
/-----> P1 ------------------------\
/ \
Gs(in) +-> Gp(in) --> P2 --> P3 --> Gp(out) -+> Gs(out)
This combination could be used to create record operation where DTMF
was to be clamped from the recording itself, but a DTMF key press is
still used to stop the recording. In this case, P1 would be a DTMF
recognizer, P2 would be a clamp primitive, and P3 a recorder as shown
by the following example. This example omits child elements and
attributes not concerned with the core concept. The following section
discusses sending events and the details of each of the primitives is
defined in section 4.
<group topology="parallel">
<dtmf/>
<group topology="serial">
<clamp/>
<record/>
</group>
</group>
A single schema, "fullduplex" is defined for a two dimensional group.
A full-duplex two dimensional group is has exactly two immediate
Saleem & Sharratt Expires - August 2006 [Page 74]
Internet-draft Media Server Markup Language February 2006
(MSML)
children. Those children may be primitives or other one dimensional
groups. A "fullduplex" group must only be used as the top most group
and must not be nested. Each primitive (P1) and group (G2) becomes
half of the full-duplex group as shown in the diagram below.
G-A(in1) +-> G2 --> G-B(out1)
G-A(out2) <-- P1 <-+ G-B(in2)
Full duplex groups are symmetrical when both halves are the same.
They are asymmetrical when they differ. Asymmetric groups need to
have a name associated with each side. The left side is defined as
the input of the first child of the full-duplex group combined with
the output of the second child. The right side is reverse. These
sides were labeled A and B respectively in the preceding diagram.
An example of a full-duplex group is the user operated gain control
mentioned at the beginning of this sub-section. The gain should
operate on the audio which a user hears, but the gain is controlled
by recognizing things such as DTMF or spoken commands in media which
the user originates. The following shows the XML tag grouping which
would accomplish this and corresponds to the media flow shown in the
diagram above. If the user's audio is not required for anything other
than control of the gain, then the <relay> is not required and the
internal group could be omitted. A complete XML description for this
is included in the examples section.
<group topology="fullduplex">
<group topology="parallel">
<dtmf/>
<relay/>
</group>
<gain/>
</group>
Primitives within a group MUST begin concurrently but MAY finish
asynchronously based upon events which they receive or their task
completes. A group MUST terminate when all of the primitives within
it have completed. If the group contains a <groupexit> element, then
the contents of that element MUST be executed as part of group
termination.
Saleem & Sharratt Expires - August 2006 [Page 75]
Internet-draft Media Server Markup Language February 2006
(MSML)
A group itself MAY receive a terminate event requesting termination.
A terminate event sent to the group causes a terminate event to be
sent to each of its currently active primitives. The <groupexit>
element is not executed until all primitives have processed their
respective terminate events.
10.8.1 <group>
The <group> element allows the contained primitives to be executed
concurrently.
Attributes:
topology: specifies a schema which defines the flow of media within
the group. Three schemas are initially defined. "fullduplex" is
specified for use with two dimensional groups. "parallel" and
"serial" are for use with one dimensional groups. The definition of
these topologies is defined in section 2. Mandatory.
id: identifies name of the group. Mandatory when groups are nested.
Events:
terminate: causes a terminate event to be sent to each element
contained within the group.
10.8.2 <groupexit>
The <groupexit> element allows events to be sent when group
processing completes. Group processing completes when all contained
primitives terminate.
Attributes:
none
Events:
none
10.9 MSML Dialog Transform Package
The MSML Dialog Transform package gathers together the simple
primitives which work as filters on half duplex media streams.
Saleem & Sharratt Expires - August 2006 [Page 76]
Internet-draft Media Server Markup Language February 2006
(MSML)
10.9.1 <vad>
Voice activity detection (VAD) is used to detect voice and silence
when speech recognition is not required. Similar to both speech and
DTMF, a VAD has different media conditions which it can match. Those
conditions can be qualified by a minimum length of time which is
required for them to be considered recognized.
Attributes:
starttimer: boolean value which defines whether the timer is
started to allow recognition of the initial condition (voice,
silence). When set to false, the starttimer event must be
received in order for the initial condition to be recognized.
The timer does not affect recognition of the transition
conditions. Default false.
Events:
starttimer: starts the timer to allow recognition of the
initial condition if it has not already been started. Has no
effect otherwise.
terminate: terminates voice activity detection.
Shadow Variables:
none
The following sections describe the child elements of <vad>.
10.9.1.1 <voice>, <silence>, <tvoice>, <tsilence>
Each child element corresponds to a condition which a VAD can detect.
The first two detect when voice or silence has been initially present
for a minimum length of time since the VAD was started. The second
two require that a transition to the voice or silence condition first
occur.
Attributes:
len: the length of time the condition must persist in order to
be recognized. In the case of <tvoice> and <tsilence>, the
length of time applies only to the final recognized condition.
sen: the maximum length of time the condition not being
detected may occur without causing the detector to begin
measuring that condition.
Saleem & Sharratt Expires - August 2006 [Page 77]
Internet-draft Media Server Markup Language February 2006
(MSML)
10.9.2 <gain>
Gain MAY be used to adjust of the gain of a media stream by a
specific amount.
attributes:
incr: an increment, expressed in dB, which will be used to
adjust the gain when "louder" and "softer" events are received.
Default is 3 dB.
amt: a specific gain to apply specified in dB.
events:
mute: self explanatory.
unmute: self explanatory.
reset: sets the gain to zero dB.
louder: makes the audio on a stream louder.
softer: makes the audio on a stream quieter.
amt: sets the gain to the specified value between -96 dB and 9
dB.
10.9.3 <agc>
Automatic gain control MAY be used to have a media server
automatically adjust the gain of a media stream.
attributes:
tgtlvl: the desired target level for AGC specified in dBm0.
maxgain: the maximum gain that AGC will apply specified in dB.
events:
mute: self explanatory.
unmute: self explanatory.
Saleem & Sharratt Expires - August 2006 [Page 78]
Internet-draft Media Server Markup Language February 2006
(MSML)
10.9.4 <gate>
A simple filter which will pass or halt media, regardless of the
format of the media stream, based on the events it receives. <gate>
shares the same mute and unmute events for compatibility with the
gain primitives <gain> and <agc>.
attributes:
initial: the values "pass" and "halt" define whether media is
initially allowed to pass. Default is to pass.
events:
mute: halts media flow through the primitive.
unmute: allows media to pass through the primitive.
10.9.5 <clamp>
This element MAY be used to filter DTMF tones from a media stream.
Media other than DTMF tones is passed unchanged.
attributes:
none.
events:
none.
10.9.6 <relay>
This element is a simple primitive which copies its input to its
output.
attributes:
none.
events:
none.
10.10 MSML Dialog Speech Package
The MSML speech package defines functionality which MAY be used for
automatic speech recognition <speech> and extends the <play>
Saleem & Sharratt Expires - August 2006 [Page 79]
Internet-draft Media Server Markup Language February 2006
(MSML)
primitive defined in the MSML Dialog Base package to include speech
synthesis. As such, this package depends on the MSML Dialog Base
package.
10.10.1 <speech>
Activates grammars or user input rules associated with speech
recognition. If multiple grammars are specified, all are activated.
All active grammars share the same timers, recognition attributes,
and <noinput> and <nomatch> elements. Each grammar may have its own
<match> element.
<speech> terminates if any of the <grammar>, <noinput>, or <nomatch>
elements are matched the maximum number of times that they are
allowed. The number of times they may match may be specified as an
attribute of <speech> or of the individual child elements.
Attributes:
noint: specifies a time period during which speech input must
be started, otherwise the associated <noinput> element is
invoked.
norect: specifies a maximum time period during in which speech
must begin to be matched, otherwise the associated <nomatch>
element is invoked.
spcmplt: specifies the length of silence necessary after speech
before a result will be finalized in the case where there is a
complete match of an active grammar. Following the silence, the
appropriate <match> element will be triggered if the result is
above the confidence level. Otherwise a <nomatch> element will
be triggered.
spincmplt: specifies the length of silence necessary after
speech before a result will be finalized in the case where
there is a incomplete match of all active grammars. Following
the silence, the <nomatch> element will be triggered.
confidence: the minimum confidence level which the recognizer
must have to consider a recognition result as matching a
grammar. Expressed as an integer between 1-100.
sens: specifies the sensitivity of the recognizer to determine
whether speech is present. Lower sensitivity may be required
for the recognizer to work well in the presence of high
background noise or line echo.
Saleem & Sharratt Expires - August 2006 [Page 80]
Internet-draft Media Server Markup Language February 2006
(MSML)
starttimer: boolean value which defines whether the no input
(noint) and no recognition (norect) are started initially. When
set to false, the starttimer event must be received in order to
start them. Default false.
iterate: specifies the number of times the <grammar>,
<noinput>, and <nomatch> elements may be executed unless those
elements specify differently. The value "forever" may be used
to indicate that these may be executed any number of times.
Default is once '1'.
Events:
sens: sets the sensitivity of the recognizer as described
above.
starttimer: starts the no input (noint) and no recognition
(norect) timers if they have not already been started. Has no
effect otherwise.
terminate: terminates the speech input and assigns values to
the shadow variables.
Shadow Variables:
speech.end: contains the event which caused the <speech> to
terminate or is assigned one of "speech.match",
"speech.noinput", or "speech.nomatch" depending upon which of
the corresponding elements reached its maximum.
speech.results: contains the results of a matched grammar. The
results are formatted using the Natural Language Semantics
Markup Language (NLSML) [6]. When this variable is referenced
to return results, the results are returned as a separate MIME
entity.
The following sections describe the child elements of <speech>.
10.10.1.1 <grammar>
Specifies and activates a speech grammar based on Speech Recognition
Grammar Specification (SRGS) [5] XML notation. Grammars may be
referenced by a URI or defined inline. Child elements of <match> MUST
be executed when the specified speech grammar is matched.
Attributes:
Saleem & Sharratt Expires - August 2006 [Page 81]
Internet-draft Media Server Markup Language February 2006
(MSML)
uri: specifies the location of an SRGS grammar when the grammar
is not defined inline.
iterate: specifies the number of times the <grammar> may be
matched. The value "forever" MAY be used to indicate that
<grammar> may be matched any number of times. This value
overrides any specified in <speech>. Default is once '1'.
10.10.1.2 <match>
<match> is a child of <grammar> and specifies the actions to take
when the corresponding grammar is matched.
10.10.1.3 <noinput>
The <noinput> element is used when speech is being recognized.
Children of the <noinput> element MUST be executed when speech has
not been detected and the no input timeout (noint) occurs.
Attributes:
iterate: specifies the number of times the <noinput> may be
triggered. The value "forever" may be used to indicate that
<noinput> may be triggered any number of times. This value
overrides any specified in <speech>. Default is once '1'.
10.10.1.4 <nomatch>
The <nomatch> element is used when speech is being recognized.
Children of the <nomatch> element MUST be executed when it is
determined that none of the active grammars will match.
Attributes:
iterate: specifies the maximum number of times the <nomatch>
may be triggered. The value "forever" MAY be used to indicate
that <nomatch> may be triggered any number of times. This value
overrides any specified in <speech>. Default is once '1'.
10.10.1.5 <speechexit>
The <speechexit> element MUST be invoked when the speech input
completes because one of <grammar>, <noinput>, or <nomatch> occurred
its maximum number of times.
Attributes:
none
Saleem & Sharratt Expires - August 2006 [Page 82]
Internet-draft Media Server Markup Language February 2006
(MSML)
10.10.2 <play>
The <play> element, as defined in the MSML Dialog Base package, is
extended with a new child element for synthesizing speech. From an
XML perspective, <tts> is a member of a media substitution group. See
the schema at the end of this document for details.
The following sections describe the child elements of <play>.
10.10.2.1 <tts>
Contents of the <tts> element are rendered using Text To Speech
services and must be compliant to the SSML specification. Element
content MAY be plain text, contain the SSML <speak> element, or the
uri attribute should identify the location of text to be rendered.
Attributes:
uri: Identifies the location of the text to be rendered. The
file and http schemes are supported.
iterate: specifies the number of times the text to speech block
is to be rendered. Defaults to once '1'.
xml:lang: specifies the language to use when it is not
explicitly specified as an attribute for <speak>.
10.11 MSML Dialog Fax Detection Package
The fax detection package defines primitives which allow a media
server to provide facsimile detection services.
10.11.1 <faxdetect>
Fax tone detection is used to detect the presence of the T.30 CNG
tone in a media stream. Child elements of <faxtone> are executed when
the CNG tone is detected.
Attributes:
None
Saleem & Sharratt Expires - August 2006 [Page 83]
Internet-draft Media Server Markup Language February 2006
(MSML)
10.12 MSML Dialog Fax Send/Receive Package
10.12.1 <faxsend>
The <faxsend> primitive provides the functionality of a calling fax
terminal. This typically means sending a set of pages. However, it
can also mean requesting the called terminal to send pages instead
of, or in addition to, sending pages. The fax images to send are
defined by the <sendobj> elements, described below.
Requesting the called terminal to send pages happens when the
<rxpoll> element is included as part of <faxsend>. This element may
be included in addition to, or instead of, the <sendobj> element. One
<sendobj> (at a minimum) or <rxpoll> element must be present. When
both are present, a media server will first send pages and will then
poll the other terminal, requesting pages.
Because fax is a distinct media type, the <faxsend> primitive is not
expected to interact with other primitives. Rather, it will interact
using fax protocols with a remote fax terminal (or gateway) and will
send requested status events to its invoking environment. During fax
operation, shadow variables are used to record the progress and
parameters of the varying stages of fax operation.
Status events are requested by including one or more status request
elements. These elements correspond to different stages or events in
fax operation and cause pre-defined events to be sent to the invoking
environment when they occur. Since the only recipient of these events
is expected to be a fax Control Agent, requests are simplified by
associating a pre-defined namelist of shadow variables with each
event. This decision may be revisited to allowed tailored namelists
based on further implementation experience. Status requests apply
both to sending and polling operation.
Attributes:
lclid: the identifier that a media server uses to identify
itself.
minspeed: the minimum acceptable speed to negotiate for the
operation.
maxspeed: the maximum speed to negotiate for the operation.
This attribute is primarily for testing purposes.
ecm: specifies whether Error Correction Mode (ECM) is allowed
to be used if supported by the remote terminal. Defaults to
"true".
Saleem & Sharratt Expires - August 2006 [Page 84]
Internet-draft Media Server Markup Language February 2006
(MSML)
Events:
terminate: terminates the fax send operation.
Shadow Variables:
fax.rmtid: the identifier of the remote fax terminal.
fax.rate: the negotiated speed for the operation.
fax.resolution: identifies the resolution of the image. Both
metric and inch based resolutions are defined. Metric based
resolutions are: 75x75, 150x150, 204x98, 204x196, 204x391,
408x391. Inch based resolutions are: 200x200, 300x300, 400x400,
600x600.
fax.pagesize: identifies the negotiated page size. Metric sizes
are "A3", "A4", "A5", "A6", and "B4". Inch based page sizes are
"Letter" and "Legal".
fax.encoding: identifies the image encoding utilized. Valid
values are "MH", "R", "MMR", and "JPEG".
fax.ecm: identifies whether ECM operation was used.
fax.pagebadlines: the number of bad lines in a page.
fax.objbadlines: the number of bad lines in an object.
fax.opbadlines: the number of bad lines in an operation.
fax.objuri: the objuri of the current object.
fax.resendcount: the number of pages resent due to errors.
fax.totalpages: the number of pages processed or stored.
fax.totalobjects: the count of the objects used in the
operation.
fax.duration: the duration of the operation expressed as a
duration in seconds and milliseconds (e.g. "23s250ms").
fax.result: contains the reason which caused the fax operation
to complete. When the operation completes successfully, the
value will be assigned "fax.success". Other values include:
"fax.partial", "fax.nofax", "fax.remotedisconnect",
"fax.uri.access.error", and "fax.invalid.startpage".
Saleem & Sharratt Expires - August 2006 [Page 85]
Internet-draft Media Server Markup Language February 2006
(MSML)
The following sections describe the child elements of <faxsend>.
10.12.1.1 <sendobj>
<sendobj> is used to define a fax transmission. There MAY be multiple
instances of the element which will be transmitted in order.
Attributes:
objuri: a URI that points to the fax image that will be
transmitted. Mandatory.
startpage: the first page of a multi-page objuri to send.
pagecount: page count.
10.12.1.2 <hdrfooter>
<hdrfooter> describes the header/footer that a media server MAY put
on pages. The header or footer may be defined as the content of the
<format> child element. The <format> element is only allowed if the
type attribute has a value of "header" or "footer".
Attributes:
type: specifies whether a header or a footer should be put on
pages and identifies the source of the header or footer. The
following enumerated values may be used:
"header" indicates that the media server should put a header
on pages using the contents of the <format>
element.
"nohdr" indicates that there should be no header or footer.
"footer" indicates that the media server should put a footer
on pages using the contents of the <format>
element.
style: defines the style of insertion onto a fax page that a
media server should use for the header or footer. Valid styles
are "append", "overlay", or "replace".
<format> is a child of the <hdrfooter> element that defines the style
format to be used for the header or footer. It uses a "C" language
style format statement (as shown below) to define the contents and
layout of the header or footer.
Saleem & Sharratt Expires - August 2006 [Page 86]
Internet-draft Media Server Markup Language February 2006
(MSML)
code length name format
%a 3 day of week 3-character abbreviation
%d 2 date 01-31
%m 2 month 01-12
%y 2 year 00-99
%Y 4 year 0000-9999
%I 2 12 hour 01-12
%H 2 24 hour 00-23
%M 2 minute 00-59
%S 2 seconds 00-59
%p 2 AM/PM AM or PM
%P 2 page number 01-99
%T 2 total pages 01-99
%l 20 local ID (sender) 0-9, + or spaces
%r 20 remote ID (rcvr) 0-9, + or spaces
%% 1 percent display % in header/ftr
10.12.1.3 <rxpoll>
<rxpoll> provides the information necessary for a receive polling
operation to occur. The object(s) to be received are defined by one
or more <rcvobj> elements. The <rcvobj> is defined further under the
child elements of <faxrcv>. The <rxpoll> element MAY also include a
description of the header/footer that a media server SHOULD put on
received pages. The <hdrfooter> element and it's usage is described
above.
Attributes:
rmtid: specifies the identifier of the remote fax terminal that
to be associated with a polling operation. A media server MUST
NOT execute a polling operation unless the value of rmtid
matches that of the connected remote machine.
10.12.1.4 <faxstart>
Requests that an event be sent when fax operation has begun. When
triggered, the following will be executed:
<send target="source" event="fax.start"/>
Saleem & Sharratt Expires - August 2006 [Page 87]
Internet-draft Media Server Markup Language February 2006
(MSML)
10.12.1.5 <faxnegotiate>
Requests that an event be sent when a negotiation has been completed.
Multiple events MAY be sent each time a DCS frame is sent or
received. When triggered, the following will be executed:
<send target="source" event="fax.negotiate"
namelist="fax.rmtid
fax.rate
fax.resolution
fax.pagesize
fax.encoding
fax.ecm"/>
10.12.1.6 <faxpagedone>
Requests that an event be sent when a page has been sent or received.
When triggered, the following will be executed:
<send target="source" event="fax.pagedone"
namelist="fax.resolution
fax.pagesize
fax.encoding
fax.pagebadlines
fax.resendcount"/>
10.12.1.7 <faxobjectdone>
Requests that an event be sent when an objuri has been completed.
When triggered, the following will be executed:
<send target="source" event="fax.objectdone"
namelist="fax.objuri
fax.objbadlines
fax.resendcount
fax.totalpages
fax.result"/>
10.12.1.8 <faxopcomplete>
Requests that an event be sent when an operation has been completed.
When triggered, the following will be executed:
Saleem & Sharratt Expires - August 2006 [Page 88]
Internet-draft Media Server Markup Language February 2006
(MSML)
<send target="source" event="fax.opcomplete"
namelist="fax.totalpages
fax.opbadlines
fax.resendcount
fax.totalobjects
fax.duration
fax.result"/>
10.12.1.9 <faxpollstarted>
Requests that an event be sent when a polling operation has started.
When triggered, the following will be executed:
<send target="source" event="fax.opcomplete"
namelist="fax.rmtid
fax.rate
fax.resolution
fax.pagesize
fax.encoding
fax.ecm"/>
10.12.2 <faxrcv>
The <faxrcv> primitive provides the functionality of a called fax
terminal. Typically this type of operation is to receive pages.
However, it can include sending pages instead of, or in addition to,
receiving them. The fax objects to receive are defined by the
<rcvobj> elements, described below.
A media server SHOULD send pages as a polled terminal when the
<txpoll> element is included as part of <faxrcv>. This element may be
included in addition to, or instead of, the <rcvobj> element. One
<rcvobj> or <txpoll> element must be present. When both are present,
a media server SHOULD first receive pages and will then allow the
other terminal to poll the media server, requesting pages.
Because fax is a distinct media type, the <faxrcv> primitive is not
expected to interact with other primitives. Rather, it will interact
using fax protocols with a remote fax terminal and will send
requested status events to its invoking environment. During fax
operation, shadow variables are used to record the progress and
parameters of the varying stages of fax operation.
Status events are requested by including one or more status request
elements. These elements correspond to different stages or events in
fax operation and cause pre-defined events to be sent to the invoking
environment when they occur. Since the only recipient of these events
is expected to be a fax Control Agent, requests are simplified by
Saleem & Sharratt Expires - August 2006 [Page 89]
Internet-draft Media Server Markup Language February 2006
(MSML)
associating a pre-defined namelist of shadow variables with each
event. This decision may be revisited to allowed tailored namelists
based on further implementation experience. Status requests apply
both to receiving and polling operation.
Attributes:
lclid: the identifier that a media server uses to identify
itself.
ecm: specifies whether ECM mode is allowed to be used if
supported by the remote terminal. Defaults to "true".
Events:
terminate: terminates the fax reception operation.
Shadow Variables:
<faxrcv> supports the same set of shadow variables as <faxsend>
The following sections describe the child elements of <faxrcv>.
In addition to the elements defined below, <faxrcv> MAY also have the
following child elements which were defined under <faxsend>:
o <hdrfooter>
o <faxstart>
o <faxnegotiate>
o <faxpagedone>
o <faxobjectdone>
o <faxopcomplete>
o <faxpollstarted>
Their meaning and usage is the same as previously defined.
10.12.2.1 <rcvobj>
<rcvobj> is used to define fax objects that a media server will
receive. There may be multiple instances of the element which will be
used in order.
Attributes:
objuri: a URI that points to the location that a received image
is to be stored. Mandatory.
Saleem & Sharratt Expires - August 2006 [Page 90]
Internet-draft Media Server Markup Language February 2006
(MSML)
maxpages: the maximum number of pages that will be stored in
objuri.
10.12.2.2 <txpoll>
<txpoll> provides the information for a polling operation to occur as
part of a fax receive operation. Multiple object(s) to be send may be
supplied by one or more <sendobj> elements. In the event of multiple
occurrences, a media server MUST select the <sendobj> element whose
rmtid attribute matches that of the remote terminal.
The <sendobj> element was defined previously as a child element of
<faxsend>. For <txpoll> is extended with an rmtid attribute that
specifies the identifier of the remote fax terminal and is used to
select the specific <sendobj> to send.
A media server SHOULD put a header/footer on transmitted pages based
on any <hdrfooter> element included as part of <txpoll>.
Attributes:
none
11. Response Codes
Response codes are used to indicate reasons for failures as well as
completion status. The appropriate code and description must be
passed to the invoking environment on failure.
The response codes defined in this section are returned as the value
of the response attribute to the <result> element. Some values may
also be returned as part of a namelist to an "msml.dialog.exit" event
generated when an executing MSML dialog fails.
Informational (1xx)
Reserved for future use
Success (200)
200 OK
Request Error (4xx)
400 Bad Request
401 Unknown Element
402 Unsupported Element
Saleem & Sharratt Expires - August 2006 [Page 91]
Internet-draft Media Server Markup Language February 2006
(MSML)
403 Missing mandatory element content
404 Forbidden element content
405 Invalid element content
406 Unknown attribute
407 Attribute not supported
408 Missing mandatory attribute
409 Forbidden attribute is present
410 Invalid attribute value
420 Unsupported media description language
421 Unknown media description language
422 Ambiguous request (both URI and inline description)
423 External document fetch error
424 Syntax error in foreign language
425 Semantic error in foreign language
426 Unknown error executing foreign language
430 Object does not exist
431 Object instance name already used
432 Conference name already in use
433 reserved
434 External document fetch error
440 Cannot join objects of the specified class
441 Objects have incompatible media types
442 reserved
443 reserved
444 Number of media inputs exceeded
450 Objects have incompatible media formats
451 Incompatible media stream format
Saleem & Sharratt Expires - August 2006 [Page 92]
Internet-draft Media Server Markup Language February 2006
(MSML)
Server Error (5xx)
500 Internal media server error
503 Service Unavailable
510 Not in service
511 Service Unavailable
520 No resource to fulfill request
521 Internal limit exceeded
12. MSML Conference Examples
These examples focus on MSML Conference Core package used by an
Control Agent (CA) to control services on a Media Server (MS). They
show the relationship between SIP signaling to establish media
sessions and MSML service control commands. For brevity, only the
content of MSML messages is shown. The examples assumes that the CA
and MS use the IPv4 address and UDP port number of the audio stream
(on the MS) to identify the MSML connection.
12.1 Establishing a Dial-in Conference
UA Control Agent Media Server
| | |
| | INVITE F1 |
| |-------------------------->|
| | 200 F2 |
| |<--------------------------|
| | ACK F3 |
| |-------------------------->|
| | |
| | createconference> F4 |
| |-------------------------->|
| | 200 F5 |
| |<--------------------------|
| INVITE (SDP UA) F6 | |
|------------------------>| |
| | INVITE (SDP UA) F7 |
| |-------------------------->|
| | 200 (SDP MS) F8 |
| |<--------------------------|
| | ACK F9 |
Saleem & Sharratt Expires - August 2006 [Page 93]
Internet-draft Media Server Markup Language February 2006
(MSML)
| |-------------------------->|
| 200 (SDP MS) F10 | |
|<------------------------| |
| ACK F11 | |
|------------------------>| |
| | <dialogstart> F12 |
| |-------------------------->|
| | 200 F13 |
| |<--------------------------|
| | HTTP interactions F14 |
| |<------------------------->|
| | <event>(dialog.exit) F15 |
| |<--------------------------|
| | <join> F16 |
| |-------------------------->|
| | 200 F17 |
| |<--------------------------|
| ... | ... |
| | |
| | <dialogstart> F18 |
| |-------------------------->|
| | 200 F19 |
| |-------------------------->|
| | HTTP interactions F20 |
| |<--------------------------|
| | <event>(dialog.exit) F21 |
| |-------------------------->|
| ... | ... |
| | |
Steps 1-3: establish an MSML control channel for the conference.
Alternatively, a control channel could already have been established
which was used for all CA/MS interactions. A control channel per
conference is only one possible model. Currently MSML uses SIP INFO
requests and responses on this SIP dialog. There is a proposal to use
this message exchange to establish a TCP channel for MSML similar to
the approach used for MRCPv2. This approach would require that a
request identifier be added to the <msml> element to correlate
requests and responses. This currently relies on the SIP INFO request
and response for this property. MSML messages are shown without
specifying the transport in this example but it assumes a
request/response correlation based on transport messages.
Step 4: create a conference that will mix the loudest two speakers
and report those speakers to the Control Agent every ten seconds. The
Saleem & Sharratt Expires - August 2006 [Page 94]
Internet-draft Media Server Markup Language February 2006
(MSML)
media server will automatically terminate remaining media sessions
and delete the conference and associated resources and when the
control channel is terminated.
<msml version="1.1">
<createconference name="exampleConf" deletewhen="nocontrol">
<audiomix>
<n-loudest n="3"/>
<asn ri="10s"/>
</audiomix>
</createconference>
</msml>
Step 5: conference created successfully
<msml version="1.1">
<result response="200"/>
</msml>
Steps 6-11: standard 3PCC establishment of a user initiated media
session to a media server. This is the equivalent of a dial-in
conference participant. The "To:" header returned by the MS in the
200 response of Step F8 was:
To: <sip:msml@ms.example.com>;tag=jd87dfg4h
Step 12: request an initial dialog with the participant to prompt for
their name, desired conference, etc. The dialog completes by
informing the participant they are joining the conference. If this
was not the first participant, the dialog could also announce the
other participants.
<msml version="1.1">
<dialogstart target="conn:jd87dfg4h" name=”12345”
type="application/vxml+xml"
src="http://server.example.com/scripts/initial.vxml"/>
</msml>
Step 13: dialog started successfully. The dialog identifier is
returned.
Saleem & Sharratt Expires - August 2006 [Page 95]
Internet-draft Media Server Markup Language February 2006
(MSML)
<msml version="1.1">
<result response="200"/>
<dialogid>conn:jd87dfg4h/dialog:12345</dialogid>
</msml>
Step 14: sequence of HTTP VoiceXML dialog interactions.
Step 15: the VoiceXML browser exits (but does not disconnect). If a
namelist had been specified within the VoiceXML <exit> element, it
would have been included in the <event> sent to the CA.
<msml version="1.1">
<event name="msml.dialog.exit"
id="conn:jd87dfg4h/dialog:12345"/>
</msml>
Step 16: join the participant to the conference and have the volume
of their contributing audio automatically adjusted to a target level
of -20 dBm0.
<msml version="1.1">
<join id1="conn:jd87dfg4h" id2="conf:exampleConf">
<stream media="audio" dir="from-id1">
<gain agc="true" tgtlvl="-20"/>
</stream>
<stream media="audio" dir="to-id1"/>
</msml>
Step 17: successfully joined to conference
<msml version="1.1">
<result response="200"/>
</msml>
Steps 6 through 17 are repeated for the second participant.
Saleem & Sharratt Expires - August 2006 [Page 96]
Internet-draft Media Server Markup Language February 2006
(MSML)
Step 18: play a join tone or message announcing the new participant
to the conference.
<msml version="1.1">
<dialogstart target="conf:exampleConf"
type="application/vxml+xml"
src="http://server.example.com/scripts/joinmsg.vxml"/>
</msml>
Step 19: dialog started successfully. The dialog identifier is
returned. Media Server assigned a unique identifier since name
attribute was not specified in <dialogstart>.
<msml version="1.1">
<result response="200"/>
<dialogid>conf:ExampleConf/dialog:j6fs8745</dialogid>
</msml>
Step 20: HTTP VoiceXML dialog interaction(s).
Step 21: the VoiceXML browser exits.
<msml version="1.1">
<event name="msml.dialog.exit"
id="conf:ExampleConf/dialog:j6fs8745"/>
</msml>
Steps 6 through 21 are repeated for the third and subsequent
participants.
12.2 Example of a Sidebar Audio Conference
This example assumes that a conference has already been established
as in the previous example. It creates a sidebar conference that
hears the main conference as a whisper. Three participants are moved
Saleem & Sharratt Expires - August 2006 [Page 97]
Internet-draft Media Server Markup Language February 2006
(MSML)
to the sidebar. After some period of time, the sidebar participants
are returned to the main conference and the sidebar is deleted.
Step1: the sidebar conference is created. It is joined half-duplex to
the main conference and a manual gain object is inserted in the media
stream. Three participants are then moved from the main conference to
the sidebar. Although not shown, an CA could include the "mark"
attribute in each element to allow recovery in the event of a mid-
transaction error.
<msml version="1.1">
<createconference name="sidebarConf"
deletewhen="nomedia">
<audiomix/>
</createconference>
<join id1="conf:sidebarConf" id2="conf:exampleConf">
<stream media="audio" dir="to-id1">
<gain amt="-20"/>
</stream>
</join>
<unjoin id1="conn:gs5s4-1" id2="conf:exampleConf"/>
<join id1="conn:gs5s4-1" id2="conf:sidebarConf"/>
<unjoin id1="conn:hd764gr9-2" id2="conf:exampleConf"/>
<join id1="conn:hd764gr9-2" id2="conf:sidebarConf"/>
<unjoin id1="conn:h37frdvgs65-3" id2="conf:exampleConf"/>
<join id1="conn:h37frdvgs65-3" id2="conf:sidebarConf"/>
</msml>
Step 2: sidebar conference created successfully and participants
joined.
<msml version="1.1">
<result response="200"/>
</msml>
Step 3: once the sidebar conference has completed, the participants
are rejoined to the main conference. The sidebar is destroyed
automatically by the MS when the last media stream is removed as
specified when the sidebar conference was created.
<msml version="1.1">
<unjoin id1="conn:gs5s4-1" id2="conf:sidebarConf"/>
<join id1="conn:gs5s4-1" id2="conf:exampleConf"/>
<unjoin id1="conn:hd764gr9-2" id2="conf:sidebarConf"/>
<join id1="conn:hd764gr9-2" id2="conf:exampleConf"/>
<unjoin id1="conn:h37frdvgs65-3" id2="conf:sidebarConf"/>
<join id1="conn:h37frdvgs65-3" id2="conf:exampleConf"/>
</msml>
Saleem & Sharratt Expires - August 2006 [Page 98]
Internet-draft Media Server Markup Language February 2006
(MSML)
Step 4: participants successfully moved to main conference and
sidebar destroyed.
<msml version="1.1">
<result response="200"/>
</msml>
12.3 Example of Removing a Conference
This example assumes a conference created similar to the first
example where there is an MSML control channel specific to the
conference and the conference has been configured to be deleted when
that channel is removed (using SIP).
Steps 1-2: the CA signals BYE for the SIP dialog used to establish
the conference control channel.
Steps 3-6: the MS initiates terminating the media sessions for each
participant remaining in the conference.
The MS deletes the conference and removes all resources when the last
participant has been removed.
12.4 Example of Modifying Video Layout
Assume that a conference named "example" is created using the
following mixer descriptions.
+---+---+
| 1 | 2 |
+---+---+
| 3 | 4 |
+---+---+
<createconference name="quad-split">
<audiomix>
<n-loudest n="3"/>
<asn ri="10s"/>
</audiomix>
<videolayout>
Saleem & Sharratt Expires - August 2006 [Page 99]
Internet-draft Media Server Markup Language February 2006
(MSML)
<root size="CIF" background="white" />
<selector id="default" method="vas" si="500ms">
<region id="1" left="0" top="0" size="1/4"/>
</selector>
<region id="2" left="50%" top="0" size="1/4"/>
<region id="3" left="0%" top="50%" size="1/4">
<region id="4" left="50%" top="50%" size="1/4"/>
</videolayout>
</createconference>
The following would change the size of the video window to QCIF and
the background color to the default "black".
<modifyconference id="conf:example">
<videolayout>
<root size="4CIF"/>
</videolayout>
</modifyconference>
The relative location of the regions does not change. However the
sizes of the regions do change because they are relative to the size
of the root window. The result is a layout that looks identical but
half the size.
The following would freeze the video displayed in region "2" without
affecting any other attributes of that region.
<modifyconference id="conf:example">
<videolayout>
<region id="2" left="50%" top="0" size="1/4"
freeze="true"/>
</videolayout>
</modifyconference>
13. MSML Dialog Examples
These examples focus on the MSML Dialog Base package and the MSML
Dialog Group package.
13.1 Announcement
The following is a simple announcement scenario. Two recorded audio
files are played in sequence followed by generated speech followed by
a variable. The results are reported once media generation completes.
<?xml version="1.0" encoding="UTF-8"?>
Saleem & Sharratt Expires - August 2006 [Page 100]
Internet-draft Media Server Markup Language February 2006
(MSML)
<msml version="1.1">
<dialogstart target=”conn:12345” name=”12345”>
<play>
<audio uri="file://clip1.wav"/>
<audio uri="http://host1/clip2.wav"/>
<tts uri="http://host2/text.ssml"/>
<var type="date" subtype="mdy" value="20030601"/>
</play>
<send target="source" event="done" namelist="play.amt
play.end"/>
</dialogstart>
</msml>
13.2 Voice Mail Retrieval
Below is an example which shows a simple voice mail retrieval
operation consisting of playing a message and allowing the user to
pause and resume play using '5' to toggle the state. The operation
would terminate when the play completed or the user entered '#'.
During the play, the user can advance forward and backward through
the message as well as rewinding to the beginning.
<?xml version="1.0" encoding="UTF-8"?>
<msml version="1.1">
<dialogstart target=”conn:12345” name=”12345”>
<group topology="parallel">
<play>
<audio uri="file://message.wav"/>
<playexit>
<send target="group" event="terminate"/>
</playexit>
</play>
<dtmf iterate="forever">
<pattern digits="5">
<send target="play" event="toggle-state"/>
</pattern>
<pattern digits="6">
<send target="play" event="forward"/>
</pattern>
<pattern digits="7">
<send target="play" event="backward"/>
</pattern>
<pattern digits="8">
<send target="play" event="restart"/>
</pattern>
<pattern digits="#">
<send target="play" event="terminate"/>
</pattern>
Saleem & Sharratt Expires - August 2006 [Page 101]
Internet-draft Media Server Markup Language February 2006
(MSML)
</dtmf>
</group>
</dialogsgtart>
</msml>
13.3 Play and Record
A more complex example is a play and record operation. This sources
and sinks media and uses voice activity DTMF detection and
recognition to influence behavior. Any DTMF input or voice activity
will barge the play and cause the record to begin. However, if the
prompt was barged with a DTMF digit of '#', the record terminates
without starting. When the play terminates, it send a starttimer
event to the VAD to allow it to recognize an initial silence
condition. The recording will be terminated (without starting) when
the VAD detects an initial 3 seconds of silence.
Once resumed (based upon voice detection) the recording may be
terminated under several conditions. It will terminate after 5
seconds of silence or after 60 seconds elapses. It will also
terminate if a '#' key is recognized. Every aspect of this behavior
can be modified by changing what is recognized and the events which
are sent. The following example uses the MSML Dialog Group package.
<?xml version="1.0" encoding="UTF-8"?>
<msml version="1.1">
<dialogstart target=”conn:12345” name=”12345”>
<group topology="parallel">
<play>
<audio uri="file://prompt.wav"/>
<playexit>
<send target="vad" event="starttimer"/>
</playexit>
</play>
<dtmf>
<pattern digits="#">
<send target="record" event="terminate.termkey"/>
</pattern>
<detect>
<send target="play" event="terminate"/>
</detect>
</dtmf>
<vad>
<voice len="10ms">
<send target="play" event="terminate"/>
<send target="record" event="resume"/>
</voice>
<silence len="3s">
Saleem & Sharratt Expires - August 2006 [Page 102]
Internet-draft Media Server Markup Language February 2006
(MSML)
<send target="record" event="nospeech"/>
</silence>
<tsilence len="5s">
<send target="record" event="terminate.finalsilence"/>
</tsilence>
</vad>
<record initial="suspend" maxtime="60s"
dest="file://record.wav" format="g729">
<recordexit>
<send target="group" event="terminate"/>
</recordexit>
</record>
<groupexit>
<send target="source" event="done"
namelist="record.len record.end"/>
</groupexit>
</group>
</dialogstart>
</msml>
The following implements the same functionality, as described above,
in using the MSML Dialog Base package, using the <record> composite
mechanism for the play and record operation.
<?xml version="1.0" encoding="UTF-8"?>
<msml version="1.1">
<dialogstart target=”conn:12345” name=”12345”>
<record prespeech=”3s” postspeech=”5s” maxtime="60s" termkey=”#”
dest="file://record.wav" format="g729">
<play barge=”true”>
<audio uri="file://prompt.wav"/>
</play>
<recordexit>
<send target="source" event="done"
namelist="record.len record.end"/>
</recordexit>
</record>
</dialogstart>
</msml>
13.4 Speech Recognition
The following simple example requests that a user speak the name of a
city and returns the result.
<?xml version="1.0" encoding="UTF-8"?>
<msml version="1.1">
<dialogstart target=”conn:12345” name=”12345”>
Saleem & Sharratt Expires - August 2006 [Page 103]
Internet-draft Media Server Markup Language February 2006
(MSML)
<group topology="parallel">
<play>
<audio uri="file://prompt.wav"/>
</play>
<speech>
<grammar version="1.0">
<rule id="city" scope="public">
<item>
<one-of>
<item>vancouver</item>
<item>new york</item>
<item>london</item>
</one-of>
</item>
</rule>
<match>
<send target="group" event="terminate"/>
</match>
</grammar>
<noinput>
<send target="group" event="terminate"/>
</noinput>
<nomatch>
<send target="group" event="terminate"/>
</nomatch>
</speech>
<groupexit>
<send target="source" event="done"
namelist="speech.end speech.results"/>
</groupexit>
</group>
</dialogstart>
</msml>
13.5 Play and Collect
This example prompts a user to enter 4 DTMF digits terminated by the
'#' key. The prompt will be barged and the user has 10 seconds to
begin entering input or no input will be indicated.
<?xml version="1.0" encoding="UTF-8"?>
<msml version="1.1">
<dialogstart target=”conn:12345” name=”12345”>
<group topology="parallel">
<play>
<audio uri="file://prompt.wav"/>
<playexit>
<send target="dtmf" event="starttimer"/>
Saleem & Sharratt Expires - August 2006 [Page 104]
Internet-draft Media Server Markup Language February 2006
(MSML)
</playexit>
</play>
<dtmf fdt="10s" idt="16s">
<pattern digits="xxxx#">
<send target="group" event="terminate"/>
</pattern>
<detect>
<send target="play" event="terminate"/>
</detect>
<noinput>
<send target="group" event="terminate"/>
</noinput>
<nomatch>
<send target="group" event="terminate"/>
</nomatch>
</dtmf>
<groupexit>
<send target="source" event="done"
namelist="dtmf.digits dtmf.end"/>
</groupexit>
</group>
</dialogstart>
</msml>
The following implements the same functionality, as described above,
using the MSML Dialog Base package, using the <collect> composite
mechanism for the play and collect operation.
<?xml version="1.0" encoding="UTF-8"?>
<msml version="1.1">
<dialogstart target=”conn:12345” name=”12345”>
<collect fdt="10s" idt="16s">
<play barge=”true”>
<audio uri="file://prompt.wav"/>
</play>
<pattern digits="xxxx#">
<send target="source" event="done"
namelist="dtmf.digits dtmf.end"/>
</pattern>
<noinput>
<send target="source" event="done"
namelist="dtmf.end"/>
</noinput>
<nomatch>
<send target="source" event="done"
namelist="dtmf.end"/>
</nomatch>
Saleem & Sharratt Expires - August 2006 [Page 105]
Internet-draft Media Server Markup Language February 2006
(MSML)
</dtmf>
</dialogstart>
</msml>
13.6 User Controlled Gain
This shows an example of nesting groups to create an arbitrary full
duplex media control. DTMF is detected on media flowing in one
direction and used to adjust the gain applied to media flowing in the
opposite direction. Additionally, the stream which is used to detect
DTMF has DTMF removed and its gain automatically adjusted before
leaving the group. This widget could be used between a conference
participant and a conference mixer.
<?xml version="1.0" encoding="UTF-8"?>
<msml version="1.0">
<dialogstart target=”conn:12345” name=”12345”>
<group topology="fullduplex">
<group topology="parallel">
<dtmf>
<pattern digits="1" iterate="forever">
<send target="gain" event="louder"/>
</pattern>
<pattern digits="2" iterate="forever">
<send target="gain" event="softer"/>
</pattern>
</dtmf>
<group topology="serial">
<clamp/>
<agc tgtlvl="0"/>
</group>
</group>
<gain amt="0" incr="5"/>
</group>
</dialogstart>
</msml>
14. Change Summary
MSML-00 is an initial draft, however it is derived from draft-
melanchuk-sipping-msml-06 [22] and draft-melanchuk-sipping-moml-06
[23]. Earlier versions of these specifications were co-authored by
Tim Melanchuk (while he was an employee of Convedia) and Garland
Sharratt. All functionality supported in [22] and [23] is supported
within this MSML specification, no new functionality is introduced in
this initial version, and there are no XML or SIP interface changes
introduced, allowing MSML-00 client/server implementations to be
fully compatible with implementations based on [22] and [23]. This
Saleem & Sharratt Expires - August 2006 [Page 106]
Internet-draft Media Server Markup Language February 2006
(MSML)
specification completely replaces earlier internet drafts MSML [22]
and MOML [23].
Additional sample scripts added and includes minor wording
corrections.
Previous versions of MSML specification are defined in this internet
draft as MSML Core and MSML Conference Core packages.
Previous versions of MOML specification are defined in this internet
draft as MSML Dialog Core, MSML Dialog Base, and all other MSML
Dialog packages.
15. Future Work
The following capabilities may be added in future versions of this
draft:
o Ability for MSML clients to audit or query the Media Server for
supported set of MSML packages and profiles.
O Ability for MSML clients to perform state auditing of current
resources allocated and in use by the Media Server.
o Ability to version MSML packages and profiles and naming scheme
for MSML extension packages.
16. XML Schema - MSML Core and MSML Conference Core Packages
The MSML schema uses one core schema which defines the MSML
Conference Core package and which includes two other schemas; one
defines the MSML datatypes, the other defines the MSML Dialog
packages.
The schema including MSML Core package and MSML Conference Core
package is:
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema elementFormDefault="qualified"
attributeFormDefault="unqualified"
xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:include schemaLocation="moml.xsd"/>
<xs:include schemaLocation="msml-datatypes.xsd"/>
<xs:element name="msml">
Saleem & Sharratt Expires - August 2006 [Page 107]
Internet-draft Media Server Markup Language February 2006
(MSML)
<xs:complexType>
<xs:choice>
<xs:group ref="msmlRequest" maxOccurs="unbounded"/>
<xs:element name="event">
<xs:complexType>
<xs:choice maxOccurs="unbounded">
<xs:sequence>
<xs:element name="name" type="msmlEventNameValue.datatype"/>
<xs:element name="value">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:pattern value="[a-zA-Z0-9.]+"/>
</xs:restriction>
</xs:simpleType>
</xs:element>
</xs:sequence>
</xs:choice>
<xs:attribute name="name" type="msmlEventName.datatype"
use="required"/>
<xs:attribute name="id" type="msmlEventSource.datatype"
use="required"/>
</xs:complexType>
</xs:element>
<xs:element name="result">
<xs:complexType>
<xs:sequence>
<xs:element name="description" minOccurs="0">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:pattern value="[a-zA-Z0-9.-_]+"/>
</xs:restriction>
</xs:simpleType>
</xs:element>
<xs:choice minOccurs="0" maxOccurs="unbounded">
<xs:element name="confid" type="confID.datatype"/>
<xs:element name="dialogid" type="dialogID.datatype"/>
</xs:choice>
</xs:sequence>
<xs:attribute name="response">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:pattern value="\d{3}"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="mark" type="mark.datatype"/>
</xs:complexType>
</xs:element>
Saleem & Sharratt Expires - August 2006 [Page 108]
Internet-draft Media Server Markup Language February 2006
(MSML)
</xs:choice>
<xs:attribute name="version" type="xs:string"
use="required" fixed="1.1"/>
</xs:complexType>
</xs:element>
<xs:group name="msmlRequest">
<xs:choice>
<xs:element name="createconference">
<xs:complexType>
<xs:all>
<xs:element name="audioMix" type="audioMixType"/>
<xs:element name="videoLayout" type="videoLayoutType"/>
<xs:element name="reserve">
<xs:complexType>
<xs:sequence>
<xs:element name="resource" maxOccurs="unbounded">
<xs:complexType>
<xs:sequence>
<xs:any namespace="##other" processContents="lax"
minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="n" type="xs:positiveInteger"
default="1"/>
<xs:anyAttribute namespace="##any"/>
</xs:complexType>
</xs:element>
</xs:sequence>
<xs:attribute name="required"
type="boolean.datatype" default="true"/>
</xs:complexType>
</xs:element>
</xs:all>
<xs:attribute name="name" type="msmlInstanceID.datatype"/>
<xs:attribute name="deletewhen" default="never">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="nomedia"/>
<xs:enumeration value="nocontrol"/>
<xs:enumeration value="never"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="term" type="boolean.datatype"
default="true"/>
<xs:attribute ref="mark"/>
</xs:complexType>
</xs:element>
<xs:element name="modifyconference">
Saleem & Sharratt Expires - August 2006 [Page 109]
Internet-draft Media Server Markup Language February 2006
(MSML)
<xs:complexType>
<xs:all>
<xs:element name="audioMix" type="audioMixType" minOccurs="0"/>
<xs:element name="videoLayout" type="videoLayoutType"
minOccurs="0"/>
</xs:all>
<xs:attribute name="id" type="confID.datatype" use="required"/>
<xs:attribute ref="mark"/>
</xs:complexType>
</xs:element>
<xs:element name="destroyconference">
<xs:complexType>
<xs:all>
<xs:element name="audioMix" type="basicAudioMixType"
minOccurs="0"/>
<xs:element name="videoLayout"
type="basicVideoLayoutType" minOccurs="0"/>
</xs:all>
<xs:attribute name="id" type="confID.datatype" use="required"/>
<xs:attribute ref="mark"/>
</xs:complexType>
</xs:element>
<xs:element name="dialogstart">
<xs:complexType>
<xs:sequence>
<xs:group ref="momlRequest"/>
<xs:group ref="sendType" minOccurs="0"/>
</xs:sequence>
<xs:attribute name="target"
type="independentID.datatype" use="required"/>
<xs:attribute name="type"
type="dialogLanguage.datatype" use="required"/>
<xs:attribute name="name" type="msmlInstanceID.datatype"/>
<xs:attribute name="src" type="xs:anyURI" use="optional"/>
<xs:attribute ref="mark"/>
</xs:complexType>
</xs:element>
<xs:element name="dialogend">
<xs:complexType>
<xs:attribute name="id" type="dialogID.datatype"
use="required"/>
<xs:attribute ref="mark"/>
</xs:complexType>
</xs:element>
<xs:element name="join">
<xs:complexType>
<xs:sequence>
<xs:element name="stream" type="streamType"
Saleem & Sharratt Expires - August 2006 [Page 110]
Internet-draft Media Server Markup Language February 2006
(MSML)
minOccurs="0" maxOccurs="4"/>
</xs:sequence>
<xs:attribute name="id1" type="independentID.datatype"
use="required"/>
<xs:attribute name="id2" type="independentID.datatype"
use="required"/>
<xs:attribute ref="mark"/>
</xs:complexType>
</xs:element>
<xs:element name="modifystream">
<xs:complexType>
<xs:sequence>
<xs:element name="stream" type="streamType" maxOccurs="4"/>
</xs:sequence>
<xs:attribute name="mark" type="mark.datatype"/>
</xs:complexType>
</xs:element>
<xs:element name="unjoin">
<xs:complexType>
<xs:sequence>
<xs:element name="stream" type="basicStreamType"
minOccurs="0" maxOccurs="4"/>
</xs:sequence>
<xs:attribute name="id1" type="independentID.datatype"
use="required"/>
<xs:attribute name="id2" type="independentID.datatype"
use="required"/>
<xs:attribute ref="mark"/>
</xs:complexType>
</xs:element>
<xs:element name="monitor">
<xs:complexType>
<xs:attribute name="id1" type="connID.datatype" use="required"/>
<xs:attribute name="id2" type="independentID.datatype"
use="required"/>
<xs:attribute name="compressed"
type="boolean.datatype" default="false"/>
<xs:attribute ref="mark"/>
</xs:complexType>
</xs:element>
<xs:element name="send">
<xs:complexType>
<xs:attribute name="event" type="msmlEvent.datatype"
use="required"/>
<xs:attribute name="target" type="msmlTarget.datatype"
use="required"/>
<xs:attribute name="valuelist" type="xs:string"/>
<xs:attribute ref="mark"/>
Saleem & Sharratt Expires - August 2006 [Page 111]
Internet-draft Media Server Markup Language February 2006
(MSML)
</xs:complexType>
</xs:element>
</xs:choice>
</xs:group>
<xs:complexType name="basicStreamType">
<xs:attribute name="dir">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="to-id1"/>
<xs:enumeration value="from-id1"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="media">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="audio"/>
<xs:enumeration value="video"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
</xs:complexType>
<xs:complexType name="streamType">
<xs:complexContent>
<xs:extension base="basicStreamType">
<xs:choice minOccurs="0" maxOccurs="unbounded">
<xs:element name="gain">
<xs:complexType>
<xs:attribute name="amt" use="optional">
<xs:simpleType>
<xs:restriction base="xs:integer">
<xs:minInclusive value="-96"/>
<xs:maxInclusive value="96"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="agc" type="boolean.datatype"/>
<xs:attribute name="tgtlvl" use="optional">
<xs:simpleType>
<xs:restriction base="xs:nonPositiveInteger">
<xs:minInclusive value="-40"/>
<xs:maxInclusive value="0"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="maxgain" default="10">
<xs:simpleType>
<xs:restriction base="xs:nonNegativeInteger">
Saleem & Sharratt Expires - August 2006 [Page 112]
Internet-draft Media Server Markup Language February 2006
(MSML)
<xs:minInclusive value="0"/>
<xs:maxInclusive value="40"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
</xs:complexType>
</xs:element>
<xs:element name="clamp">
<xs:complexType>
<xs:attribute name="dtmf" type="boolean.datatype"/>
<xs:attribute name="tones" type="boolean.datatype"/>
</xs:complexType>
</xs:element>
<xs:element name="visual"/>
</xs:choice>
<xs:attribute name="preferred" type="boolean.datatype"/>
<xs:attribute name="display" type="xs:string"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<xs:complexType name="basicAudioMixType">
<xs:attribute name="id" type="xs:string" use="required"/>
</xs:complexType>
<xs:complexType name="audioMixType">
<xs:complexContent>
<xs:extension base="basicAudioMixType">
<xs:all>
<xs:element name="asn" minOccurs="0">
<xs:complexType>
<xs:attribute name="ri" type="posDuration.datatype"/>
</xs:complexType>
</xs:element>
<xs:element name="n-loudest" minOccurs="0">
<xs:complexType>
<xs:attribute name="n" type="xs:positiveInteger"
use="required"/>
</xs:complexType>
</xs:element>
</xs:all>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<xs:complexType name="basicVideoLayoutType">
<xs:attribute name="id" type="xs:string" use="required"/>
<xs:attribute name="type" type="xs:string"
use="required" fixed="text/msml-basic-layout"/>
</xs:complexType>
<xs:complexType name="videoLayoutType">
Saleem & Sharratt Expires - August 2006 [Page 113]
Internet-draft Media Server Markup Language February 2006
(MSML)
<xs:complexContent>
<xs:extension base="basicVideoLayoutType">
<xs:choice>
<xs:element name="selector">
<xs:complexType>
<xs:complexContent>
<xs:extension base="selectorType">
<xs:sequence>
<xs:element name="root" type="rootType"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:element>
<xs:sequence>
<xs:element name="root" type="rootType"/>
<xs:choice maxOccurs="unbounded">
<xs:element name="selector" minOccurs="0"
maxOccurs="unbounded">
<xs:complexType>
<xs:complexContent>
<xs:extension base="selectorType">
<xs:sequence>
<xs:element name="region"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:element>
<xs:element name="region" minOccurs="0" maxOccurs="unbounded">
<xs:complexType>
<xs:complexContent>
<xs:extension base="regionType"/>
</xs:complexContent>
</xs:complexType>
</xs:element>
</xs:choice>
</xs:sequence>
</xs:choice>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<xs:complexType name="regionType">
<xs:attribute name="id" type="xs:string" use="required"/>
<xs:attribute name="left" type="xs:positiveInteger"/>
<xs:attribute name="top" type="xs:positiveInteger"/>
<xs:attribute name="relativeSize">
<xs:simpleType>
Saleem & Sharratt Expires - August 2006 [Page 114]
Internet-draft Media Server Markup Language February 2006
(MSML)
<xs:restriction base="xs:string">
<xs:enumeration value="1/4"/>
<xs:enumeration value="1/3"/>
<xs:enumeration value="2/3"/>
<xs:enumeration value="3/4"/>
<xs:enumeration value="1"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="priority">
<xs:simpleType>
<xs:restriction base="xs:float">
<xs:minInclusive value="0"/>
<xs:maxExclusive value="1"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="title" type="xs:string"/>
<xs:attribute name="titleTextColor" type="xs:string"/>
<xs:attribute name="titleBackgroundColor" type="xs:string"/>
<xs:attribute name="borderColor" type="xs:string"/>
<xs:attribute name="borderWidth" type="xs:positiveInteger"/>
<xs:attribute name="logo" type="xs:anyURI"/>
</xs:complexType>
<xs:complexType name="selectorType">
<xs:attribute name="id" type="xs:string" use="required"/>
<xs:attribute name="method" use="required">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="vas"/>
<xs:enumeration value="sequence"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="status" default="active">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="active"/>
<xs:enumeration value="disabled"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="si" type="posDuration.datatype" default="1s"/>
<xs:attribute name="blankothers" type="xs:boolean"
default="false"/>
<xs:attribute name="speakersees" default="current">
<xs:simpleType>
<xs:restriction base="xs:string">
Saleem & Sharratt Expires - August 2006 [Page 115]
Internet-draft Media Server Markup Language February 2006
(MSML)
<xs:enumeration value="current"/>
<xs:enumeration value="previous"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
</xs:complexType>
<xs:complexType name="rootType">
<xs:attribute name="size" default="CIF">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="16CIF"/>
<xs:enumeration value="4CIF"/>
<xs:enumeration value="CIF"/>
<xs:enumeration value="QCIF"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="backgroundcolor" type="xs:string"
default="black"/>
<xs:attribute name="backgroundimage" type="xs:anyURI"/>
</xs:complexType>
<xs:attribute name="mark" type="mark.datatype"/>
</xs:schema>
Following schema defines the basic MSML datatypes used by the schema
defined above. Note that several regular expressions required them to
be split across two lines for formatting reasons.
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema elementFormDefault="qualified"
attributeFormDefault="unqualified"
xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:simpleType name="conferenceType.datatype">
<xs:restriction base="xs:string">
<xs:enumeration value="audio.basic"/>
<xs:enumeration value="audio.advanced"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="msmlInstanceID.datatype">
<xs:restriction base="xs:string">
<xs:pattern value="[a-zA-Z0-9.:-_]+"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="connID.datatype">
<xs:restriction base="xs:string">
Saleem & Sharratt Expires - August 2006 [Page 116]
Internet-draft Media Server Markup Language February 2006
(MSML)
<xs:pattern value="conn:[a-zA-Z0-9.:-_]+"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="confID.datatype">
<xs:restriction base="xs:string">
<xs:pattern value="conf:[a-zA-Z0-9.:-_]+"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="operatorID.datatype">
<xs:restriction base="xs:string">
<xs:pattern value="conf:[a-zA-Z0-9.:-_]+"/>
<xs:pattern value="conn:[a-zA-Z0-9.:-_]+"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="dialogID.datatype">
<xs:restriction base="xs:string">
<xs:pattern value="conf:[a-zA-Z0-9.:-_]+/dialog:[a-zA-Z0-9.:-
_]+"/>
<xs:pattern value="conn:[a-zA-Z0-9.:-_]+/dialog:[a-zA-Z0-9.:-
_]+"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="independentID.datatype">
<xs:restriction base="xs:string">
<xs:pattern value="conf:[a-zA-Z0-9.:-_]+"/>
<xs:pattern value="conn:[a-zA-Z0-9.:-_]+"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="duplex.datatype">
<xs:restriction base="xs:string">
<xs:enumeration value="half"/>
<xs:enumeration value="full"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="confclass.datatype">
<xs:restriction base="xs:string">
<xs:enumeration value="standard"/>
<xs:enumeration value="preferred"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="dialogLanguage.datatype">
<xs:restriction base="xs:string">
<xs:enumeration value="application/moml+xml"/>
<xs:enumeration value="application/voicexml+xml"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="msmlEvent.datatype">
<xs:restriction base="xs:string"/>
Saleem & Sharratt Expires - August 2006 [Page 117]
Internet-draft Media Server Markup Language February 2006
(MSML)
</xs:simpleType>
<xs:simpleType name="msmlEventName.datatype">
<xs:restriction base="xs:string">
<xs:pattern value="msml.dialog.exit"/>
<xs:pattern value="msml.conf.asn"/>
<xs:pattern value="msml.conf.nomedia"/>
<xs:pattern value="msml.dialog.exit"/>
<xs:pattern value="[a-zA-Z0-9.:_-]+"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="msmlTarget.datatype">
<xs:restriction base="xs:string">
<xs:pattern value="conf:[a-zA-Z0-9.:_-]+(/oper:[a-zA-Z0-9.:_-
]+|\*)*"/>
<xs:pattern value="conn:[a-zA-Z0-9.:_-]+(/oper:[a-zA-Z0-9.:_-
]+|\*)+"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="msmlEventSource.datatype">
<xs:restriction base="xs:string">
<xs:pattern value="conf:[a-zA-Z0-9.:_-]+"/>
<xs:pattern
value="(conf:[a-zA-Z0-9.:_-]+|conn:[a-zA-Z0-9.:_-]+)
/dialog:[a-zA-Z0-9.:_-]+"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="msmlEventNameValue.datatype">
<xs:restriction base="xs:string"/>
</xs:simpleType>
<xs:simpleType name="mark.datatype">
<xs:restriction base="xs:string">
<xs:pattern value="[a-zA-Z0-9.:-_]+"/>
</xs:restriction>
</xs:simpleType>
</xs:schema>
17. XML Schema – MSML Dialog/Transform/Speech/Fax Packages
The following set of schemas collectively define the MSML Dialog
packages.
Note: the following schema is only needed when use of root element
<moml> is required.
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema elementFormDefault="unqualified"
Saleem & Sharratt Expires - August 2006 [Page 118]
Internet-draft Media Server Markup Language February 2006
(MSML)
attributeFormDefault="unqualified"
xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:include schemaLocation="moml-group-module.xsd"/>
<xs:include schemaLocation="moml-basic-primitives-module.xsd"/>
<xs:include schemaLocation="moml-transform-primitives-module.xsd"/>
<xs:include schemaLocation="moml-speech-module.xsd"/>
<xs:element name="moml">
<xs:complexType>
<xs:choice>
<xs:group ref="momlRequest"/>
<xs:element ref="event"/>
</xs:choice>
<xs:attribute name="version" type="xs:string"
use="required" fixed="1.0"/>
<xs:attribute name="id" type="momlID.datatype" use="required"/>
</xs:complexType>
</xs:element>
</xs:schema>
Following is the schema which defines the MSML Dialog datatypes
(moml-datatypes.xsd). It is included by each of the other MSML Dialog
packages.
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified"
attributeFormDefault="unqualified">
<xs:simpleType name="momlID.datatype">
<xs:restriction base="xs:string">
<xs:pattern value="[a-zA-Z0-9][a-zA-Z0-9._\-]*"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="momlEvent.datatype">
<xs:restriction base="xs:string">
<xs:pattern value="[a-zA-Z0-9][a-zA-Z0-9._\-]*"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="momlNamelist.datatype">
<xs:restriction base="xs:string"/>
</xs:simpleType>
<xs:simpleType name="dtmfDigits.datatype">
<xs:restriction base="xs:string">
<xs:pattern value="[0-9#*]+"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="iterate.datatype">
<xs:union memberTypes="xs:positiveInteger">
Saleem & Sharratt Expires - August 2006 [Page 119]
Internet-draft Media Server Markup Language February 2006
(MSML)
<xs:simpleType>
<xs:restriction base="xs:negativeInteger">
<xs:minInclusive value="-1"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="forever"/>
</xs:restriction>
</xs:simpleType>
</xs:union>
</xs:simpleType>
<xs:simpleType name="momlTarget.datatype">
<xs:restriction base="xs:string">
<xs:pattern value="[a-zA-Z0-9][a-zA-Z0-9._\-]*"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="boolean.datatype">
<xs:restriction base="xs:string">
<xs:enumeration value="true"/>
<xs:enumeration value="false"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="duration.datatype">
<xs:restriction base="xs:string">
<xs:pattern value="(\+|\-)?([0-9]*\.)?[0-9]+(ms|s)"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="posDuration.datatype">
<xs:restriction base="xs:string">
<xs:pattern value="(\+)?([0-9]*\.)?[0-9]+(ms|s)"/>
</xs:restriction>
</xs:simpleType>
</xs:schema>
Following is the schema which defines the Dialog core package (moml-
core-module.xsd). It is included by each of the other MSML Dialog
packages.
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
elementFormDefault="unqualified"
attributeFormDefault="unqualified">
<xs:include schemaLocation="moml-datatypes.xsd"/>
<xs:group name="momlRequest">
<xs:choice maxOccurs="unbounded">
<xs:group ref="executeType"/>
Saleem & Sharratt Expires - August 2006 [Page 120]
Internet-draft Media Server Markup Language February 2006
(MSML)
<xs:element ref="send" maxOccurs="unbounded"/>
</xs:choice>
</xs:group>
<xs:element name="primitive" type="primitiveType" abstract="true"/>
<xs:complexType name="primitiveType">
<xs:attribute name="id" type="momlID.datatype"/>
</xs:complexType>
<xs:element name="control" abstract="true"/>
<xs:group name="executeType">
<xs:choice maxOccurs="unbounded">
<xs:element ref="primitive"/>
<xs:element ref="control"/>
</xs:choice>
</xs:group>
<xs:group name="sendType">
<xs:choice>
<xs:choice>
<xs:element name="exit" type="exitType"/>
<xs:element name="disconnect" type="exitType"/>
</xs:choice>
<xs:sequence>
<xs:element ref="send" maxOccurs="unbounded"/>
<xs:choice minOccurs="0">
<xs:element name="exit" type="exitType"/>
<xs:element name="disconnect" type="exitType"/>
</xs:choice>
</xs:sequence>
</xs:choice>
</xs:group>
<xs:element name="send">
<xs:complexType>
<xs:attribute name="event" type="momlEvent.datatype"
use="required"/>
<xs:attribute name="target" type="momlTarget.datatype"
use="required"/>
<xs:attribute name="namelist" type="momlNamelist.datatype"/>
</xs:complexType>
</xs:element>
<xs:complexType name="exitType">
<xs:attribute name="namelist" type="momlNamelist.datatype"/>
</xs:complexType>
<xs:element name="event">
<xs:complexType>
<xs:sequence maxOccurs="unbounded">
<xs:element name="name" type="xs:string"/>
<xs:element name="value" type="xs:string"/>
</xs:sequence>
<xs:attribute name="name" type="xs:string" use="required"/>
Saleem & Sharratt Expires - August 2006 [Page 121]
Internet-draft Media Server Markup Language February 2006
(MSML)
<xs:attribute name="id" type="xs:string" use="required"/>
</xs:complexType>
</xs:element>
</xs:schema>
The schema for the MSML Dialog Base package (moml-basic-primitives-
module.xsd) is:
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema elementFormDefault="unqualified"
attributeFormDefault="unqualified"
xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:include schemaLocation="moml-datatypes.xsd"/>
<xs:include schemaLocation="moml-core-module.xsd"/>
<xs:import namespace="http://www.w3.org/XML/1998/namespace"
schemaLocation="http://www.w3.org/2001/xml.xsd"/>
<xs:element name="play" substitutionGroup="primitive">
<xs:complexType>
<xs:complexContent>
<xs:extension base="primitiveType">
<xs:sequence>
<xs:choice maxOccurs="unbounded">
<xs:element name="audio" minOccurs="0"
maxOccurs="unbounded">
<xs:complexType>
<xs:attribute name="uri" type="xs:anyURI"
use="required"/>
<xs:attribute name="iterate"
type="iterate.datatype" default="1"/>
<xs:attribute name="format" type="xs:string"
use="optional"/>
<xs:attribute name="audiosamplerate"
type="xs:positiveInteger"
use="optional"/>
<xs:attribute name="audiosamplesize"
type="xs:positiveInteger"
use="optional"/>
<xs:attribute ref="xml:lang"/>
</xs:complexType>
</xs:element>
<xs:element name="video" minOccurs="0"
maxOccurs="unbounded">
<xs:complexType>
<xs:attribute name="uri" type="xs:anyURI"
use="required"/>
<xs:attribute name="iterate"
Saleem & Sharratt Expires - August 2006 [Page 122]
Internet-draft Media Server Markup Language February 2006
(MSML)
type="iterate.datatype"
use="optional" default="1"/>
<xs:attribute name="format" type="xs:string"
use="optional"/>
<xs:attribute name="audiosamplerate"
type="xs:positiveInteger"
use="optional"/>
<xs:attribute name="audiosamplesize"
type="xs:positiveInteger"
use="optional"/>
<xs:attribute name="codecconfig" type="xs:string"
use="optional"/>
<xs:attribute name="profile" type="xs:string"
use="optional"/>
<xs:attribute name="level" type="xs:string"
use="optional"/>
<xs:attribute name="imagewidth"
type="xs:positiveInteger"
use="optional"/>
<xs:attribute name="imageheight"
type="xs:positiveInteger"
use="optional"/>
<xs:attribute name="maxbitrate"
type="xs:positiveInteger"
use="optional"/>
<xs:attribute name="framerate"
type="xs:positiveInteger"
use="optional"/>
</xs:complexType>
</xs:element>
<xs:element name="media" minOccurs="0"
maxOccurs="unbounded">
<xs:complexType>
<xs:choice>
<xs:element name="audio" minOccurs="0">
<xs:complexType>
<xs:attribute name="uri" type="xs:anyURI"
use="required"/>
<xs:attribute name="iterate"
type="iterate.datatype"
default="1"/>
<xs:attribute name="format" type="xs:string"
use="optional"/>
<xs:attribute name="audiosamplerate"
type="xs:positiveInteger"
use="optional"/>
<xs:attribute name="audiosamplesize"
type="xs:positiveInteger"
Saleem & Sharratt Expires - August 2006 [Page 123]
Internet-draft Media Server Markup Language February 2006
(MSML)
use="optional"/>
<xs:attribute ref="xml:lang"/>
</xs:complexType>
</xs:element>
<xs:element name="video" minOccurs="0">
<xs:complexType>
<xs:attribute name="uri" type="xs:anyURI"
use="required"/>
<xs:attribute name="iterate"
type="iterate.datatype"
use="optional" default="1"/>
<xs:attribute name="format" type="xs:string"
use="optional"/>
<xs:attribute name="audiosamplerate"
type="xs:positiveInteger"
use="optional"/>
<xs:attribute name="audiosamplesize"
type="xs:positiveInteger"
use="optional"/>
<xs:attribute name="codecconfig"
type="xs:string"
use="optional"/>
<xs:attribute name="profile" type="xs:string"
use="optional"/>
<xs:attribute name="level" type="xs:string"
use="optional"/>
<xs:attribute name="imagewidth"
type="xs:positiveInteger"
use="optional"/>
<xs:attribute name="imageheight"
type="xs:positiveInteger"
use="optional"/>
<xs:attribute name="maxbitrate"
type="xs:positiveInteger"
use="optional"/>
<xs:attribute name="framerate"
type="xs:positiveInteger"
use="optional"/>
</xs:complexType>
</xs:element>
</xs:choice>
</xs:complexType>
</xs:element>
<xs:element ref="smedia" minOccurs="0"
maxOccurs="unbounded"/>
</xs:choice>
<xs:choice minOccurs="0">
<xs:element name="playexit">
Saleem & Sharratt Expires - August 2006 [Page 124]
Internet-draft Media Server Markup Language February 2006
(MSML)
<xs:complexType>
<xs:group ref="sendType"/>
</xs:complexType>
</xs:element>
</xs:choice>
</xs:sequence>
<xs:attribute name="interval" type="posDuration.datatype"
use="optional"/>
<xs:attribute name="iterate" type="iterate.datatype"
use="optional" default="1"/>
<xs:attribute name="offset" type="duration.datatype"
use="optional"/>
<xs:attribute name="initial" use="optional"
default="generate">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="generate"/>
<xs:enumeration value="suspend"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="maxtime" type="posDuration.datatype"
use="optional"/>
<xs:attribute name="skip" type="duration.datatype"
use="optional" default="3s"/>
<xs:attribute name="barge" type="boolean.datatype"
use="optional" default="false"/>
<xs:attribute name="cleardb" type="boolean.datatype"
use="optional" default="false"/>
<xs:attribute ref="xml:lang"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:element>
<xs:element name="record" substitutionGroup="primitive">
<xs:complexType>
<xs:complexContent>
<xs:extension base="primitiveType">
<xs:choice minOccurs="0">
<xs:element ref="play" minOccurs="0"/>
<xs:element name="recordexit">
<xs:complexType>
<xs:group ref="sendType"/>
</xs:complexType>
</xs:element>
</xs:choice>
<xs:attribute name="append" type="boolean.datatype"
use="optional" default="false"/>
Saleem & Sharratt Expires - August 2006 [Page 125]
Internet-draft Media Server Markup Language February 2006
(MSML)
<xs:attribute name="dest" type="xs:anyURI" use="optional"/>
<xs:attribute name="audiodest" type="xs:anyURI"
use="optional"/>
<xs:attribute name="videodest" type="xs:anyURI"
use="optional"/>
<xs:attribute name="format" use="required">
<xs:simpleType>
<xs:restriction base="xs:string"/>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="codecconfig" use="optional">
<xs:simpleType>
<xs:restriction base="xs:string"/>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="audiosamplerate"
type="xs:positiveInteger" use="optional"/>
<xs:attribute name="audiosamplesize"
type="xs:positiveInteger" use="optional"/>
<xs:attribute name="profile" use="optional">
<xs:simpleType>
<xs:restriction base="xs:string"/>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="level" use="optional">
<xs:simpleType>
<xs:restriction base="xs:string"/>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="imagewidth" type="xs:positiveInteger"
use="optional"/>
<xs:attribute name="imageheight" type="xs:positiveInteger"
use="optional"/>
<xs:attribute name="maxbitrate" type="xs:positiveInteger"
use="optional"/>
<xs:attribute name="framerate" type="xs:positiveInteger"
use="optional"/>
<xs:attribute name="maxtime" type="posDuration.datatype"
use="required"/>
<xs:attribute name="initial" use="optional"
default="create">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="create"/>
<xs:enumeration value="suspend"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
Saleem & Sharratt Expires - August 2006 [Page 126]
Internet-draft Media Server Markup Language February 2006
(MSML)
<xs:attribute name="prespeech" type="posDuration.datatype"
use="optional" default="0s"/>
<xs:attribute name="postspeech" type="posDuration.datatype"
use="optional" default="0s"/>
<xs:attribute name="termkey" use="optional">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:pattern value="[0-9#*ABCD]"/>
<xs:enumeration value="create"/>
<xs:enumeration value="suspend"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:element>
<xs:element name="dtmf" substitutionGroup="primitive">
<xs:complexType>
<xs:complexContent>
<xs:extension base="primitiveType">
<xs:sequence>
<xs:element name="pattern" maxOccurs="unbounded">
<xs:complexType>
<xs:group ref="sendType"/>
<xs:attribute name="digits" type="xs:string"
use="required"/>
<xs:attribute name="format">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="mgcp"/>
<xs:enumeration value="megaco"/>
<xs:enumeration value="moml+digits"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="iterate" type="iterate.datatype"
default="1"/>
</xs:complexType>
</xs:element>
<xs:element name="detect" minOccurs="0">
<xs:complexType>
<xs:group ref="sendType"/>
</xs:complexType>
</xs:element>
<xs:element name="noinput" type="iterateSendType"
minOccurs="0"/>
<xs:element name="nomatch" type="iterateSendType"
Saleem & Sharratt Expires - August 2006 [Page 127]
Internet-draft Media Server Markup Language February 2006
(MSML)
minOccurs="0"/>
<xs:element name="dtmfexit" minOccurs="0">
<xs:complexType>
<xs:group ref="sendType"/>
</xs:complexType>
</xs:element>
<xs:element ref="play" minOccurs="0"/>
</xs:sequence>
<xs:attribute name="cleardb" type="boolean.datatype"
default="true"/>
<xs:attribute name="fdt" type="posDuration.datatype"
default="0s"/>
<xs:attribute name="idt" type="posDuration.datatype"
default="4s"/>
<xs:attribute name="edt" type="posDuration.datatype"
default="4s"/>
<xs:attribute name="starttimer" type="boolean.datatype"
default="false"/>
<xs:attribute name="iterate" type="iterate.datatype"
default="1"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:element>
<xs:element name="collect" substitutionGroup="primitive">
<xs:complexType>
<xs:complexContent>
<xs:extension base="primitiveType">
<xs:sequence>
<xs:element name="pattern" maxOccurs="unbounded">
<xs:complexType>
<xs:group ref="sendType"/>
<xs:attribute name="digits" type="xs:string"
use="required"/>
<xs:attribute name="format">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="mgcp"/>
<xs:enumeration value="megaco"/>
<xs:enumeration value="moml+digits"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="iterate" type="iterate.datatype"
default="1"/>
</xs:complexType>
</xs:element>
<xs:element name="detect" minOccurs="0">
Saleem & Sharratt Expires - August 2006 [Page 128]
Internet-draft Media Server Markup Language February 2006
(MSML)
<xs:complexType>
<xs:group ref="sendType"/>
</xs:complexType>
</xs:element>
<xs:element name="noinput" type="iterateSendType"
minOccurs="0"/>
<xs:element name="nomatch" type="iterateSendType"
minOccurs="0"/>
<xs:element name="dtmfexit" minOccurs="0">
<xs:complexType>
<xs:group ref="sendType"/>
</xs:complexType>
</xs:element>
<xs:element ref="play" minOccurs="0"/>
</xs:sequence>
<xs:attribute name="cleardb" type="boolean.datatype"
default="true"/>
<xs:attribute name="fdt" type="posDuration.datatype"
default="0s"/>
<xs:attribute name="idt" type="posDuration.datatype"
default="4s"/>
<xs:attribute name="edt" type="posDuration.datatype"
default="4s"/>
<xs:attribute name="starttimer" type="boolean.datatype"
default="false"/>
<xs:attribute name="iterate" type="iterate.datatype"
default="1"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:element>
<xs:element name="dtmfgen" substitutionGroup="primitive">
<xs:complexType>
<xs:complexContent>
<xs:extension base="primitiveType">
<xs:choice minOccurs="0">
<xs:element name="dtmfgenexit">
<xs:complexType>
<xs:group ref="sendType"/>
</xs:complexType>
</xs:element>
</xs:choice>
<xs:attribute name="level" use="optional" default="-6">
<xs:simpleType>
<xs:restriction base="xs:nonPositiveInteger">
<xs:maxInclusive value="0"/>
<xs:minInclusive value="-96"/>
</xs:restriction>
Saleem & Sharratt Expires - August 2006 [Page 129]
Internet-draft Media Server Markup Language February 2006
(MSML)
</xs:simpleType>
</xs:attribute>
<xs:attribute name="digits" type="dtmfDigits.datatype"
use="required"/>
<xs:attribute name="dur" type="posDuration.datatype"
use="optional" default="100ms"/>
<xs:attribute name="interval" type="posDuration.datatype"
use="optional" default="100ms"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:element>
<xs:complexType name="iterateSendType">
<xs:group ref="sendType"/>
<xs:attribute name="iterate" type="iterate.datatype"
default="1"/>
</xs:complexType>
<xs:element name="smedia" type="smediaType" abstract="true"/>
<xs:complexType name="smediaType">
<xs:attribute ref="xml:lang"/>
<xs:attribute name="iterate" type="iterate.datatype"/>
</xs:complexType>
<xs:element name="var" substitutionGroup="smedia">
<xs:complexType>
<xs:complexContent>
<xs:extension base="smediaType">
<xs:attribute name="type" use="required">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="date"/>
<xs:enumeration value="digits"/>
<xs:enumeration value="duration"/>
<xs:enumeration value="month"/>
<xs:enumeration value="money"/>
<xs:enumeration value="number"/>
<xs:enumeration value="silence"/>
<xs:enumeration value="time"/>
<xs:enumeration value="weekday"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="subtype" type="xs:string"
use="optional"/>
<xs:attribute name="value" type="xs:string"
use="required"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
Saleem & Sharratt Expires - August 2006 [Page 130]
Internet-draft Media Server Markup Language February 2006
(MSML)
</xs:element>
</xs:schema>
The schema for the MSML Dialog Group package (moml-group-module.xsd)
is:
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
elementFormDefault="unqualified"
attributeFormDefault="unqualified">
<xs:include schemaLocation="moml-datatypes.xsd"/>
<xs:include schemaLocation="moml-core-module.xsd"/>
<xs:element name="group" substitutionGroup="control">
<xs:complexType>
<xs:sequence>
<xs:group ref="executeType"/>
<xs:element name="groupexit" minOccurs="0">
<xs:complexType>
<xs:group ref="sendType"/>
</xs:complexType>
</xs:element>
</xs:sequence>
<xs:attribute name="id" type="momlID.datatype"/>
<xs:attribute name="topology" use="required">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="serial"/>
<xs:enumeration value="parallel"/>
<xs:enumeration value="fullduplex"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
</xs:complexType>
</xs:element>
</xs:schema>
The schema for the MSML Dialog Transform package (moml-transform-
primitives-module.xsd) is:
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
elementFormDefault="unqualified"
attributeFormDefault="unqualified">
Saleem & Sharratt Expires - August 2006 [Page 131]
Internet-draft Media Server Markup Language February 2006
(MSML)
<xs:include schemaLocation="moml-datatypes.xsd"/>
<xs:include schemaLocation="moml-core-module.xsd"/>
<xs:import namespace="http://www.w3.org/XML/1998/namespace"
schemaLocation="http://www.w3.org/2001/xml.xsd"/>
<xs:element name="vad" substitutionGroup="primitive">
<xs:complexType>
<xs:complexContent>
<xs:extension base="primitiveType">
<xs:all>
<xs:element name="voice" type="vadPatternType" minOccurs="0"/>
<xs:element name="silence" type="vadPatternType" minOccurs="0"/>
<xs:element name="tvoice" type="vadPatternType" minOccurs="0"/>
<xs:element name="tsilence" type="vadPatternType" minOccurs="0"/>
</xs:all>
<xs:attribute name="starttimer" type="boolean.datatype"
default="false"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:element>
<xs:element name="gain" substitutionGroup="primitive">
<xs:complexType>
<xs:complexContent>
<xs:extension base="primitiveType">
<xs:attribute name="incr" default="3">
<xs:simpleType>
<xs:restriction base="xs:positiveInteger">
<xs:maxInclusive value="96"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="amt" use="required">
<xs:simpleType>
<xs:restriction base="xs:integer">
<xs:minInclusive value="-96"/>
<xs:maxInclusive value="96"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:element>
<xs:element name="agc" substitutionGroup="primitive">
<xs:complexType>
<xs:complexContent>
<xs:extension base="primitiveType">
<xs:attribute name="tgtlvl" use="required">
Saleem & Sharratt Expires - August 2006 [Page 132]
Internet-draft Media Server Markup Language February 2006
(MSML)
<xs:simpleType>
<xs:restriction base="xs:nonPositiveInteger">
<xs:minInclusive value="-40"/>
<xs:maxInclusive value="0"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="maxgain" default="10">
<xs:simpleType>
<xs:restriction base="xs:nonNegativeInteger">
<xs:minInclusive value="0"/>
<xs:maxInclusive value="40"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:element>
<xs:element name="gate" substitutionGroup="primitive">
<xs:complexType>
<xs:complexContent>
<xs:extension base="primitiveType">
<xs:attribute name="initial" default="pass">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="pass"/>
<xs:enumeration value="halt"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:element>
<xs:element name="clamp" substitutionGroup="primitive">
<xs:complexType>
<xs:complexContent>
<xs:extension base="primitiveType"/>
</xs:complexContent>
</xs:complexType>
</xs:element>
<xs:element name="relay" substitutionGroup="primitive">
<xs:complexType>
<xs:complexContent>
<xs:extension base="primitiveType"/>
</xs:complexContent>
</xs:complexType>
Saleem & Sharratt Expires - August 2006 [Page 133]
Internet-draft Media Server Markup Language February 2006
(MSML)
</xs:element>
<xs:complexType name="vadPatternType">
<xs:group ref="sendType"/>
<xs:attribute name="iterate" type="iterate.datatype" default="1"/>
<xs:attribute name="len" type="posDuration.datatype"
use="required"/>
<xs:attribute name="sen" type="posDuration.datatype"
use="optional"/>
</xs:complexType>
</xs:schema>
Following is the schema for the MSML Speech package (moml-speech-
module.xsd). Note that several URL were split across several lines
for formatting reasons.
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema elementFormDefault="qualified"
attributeFormDefault="unqualified"
xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:include schemaLocation="moml-datatypes.xsd"/>
<xs:include schemaLocation="moml-core-module.xsd"/>
<xs:include schemaLocation="moml-basic-primitives-module.xsd"/>
<xs:include schemaLocation="http://www.w3.org/TR/2002/WD-speech-
synthesis-20020405/synthesis-core.xsd"/>
<xs:include schemaLocation="http://www.w3.org/TR/speech-
grammar/grammar-core.xsd"/>
<xs:element name="speech" substitutionGroup="primitive">
<xs:complexType>
<xs:complexContent>
<xs:extension base="primitiveType">
<xs:sequence>
<xs:element name="grammar" maxOccurs="unbounded">
<xs:complexType>
<xs:complexContent>
<xs:extension base="grammar">
<xs:choice>
<xs:element name="match" type="iterateSendType"
minOccurs="0"/>
</xs:choice>
<xs:attribute name="uri" type="xs:anyURI"/>
<xs:attribute name="iterate" type="iterate.datatype"
default="1"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:element>
<xs:element name="noinput" type="iterateSendType"
Saleem & Sharratt Expires - August 2006 [Page 134]
Internet-draft Media Server Markup Language February 2006
(MSML)
minOccurs="0"/>
<xs:element name="nomatch" type="iterateSendType"
minOccurs="0"/>
<xs:element name="speechexit" minOccurs="0">
<xs:complexType>
<xs:group ref="sendType"/>
</xs:complexType>
</xs:element>
</xs:sequence>
<xs:attribute name="noint" type="posDuration.datatype"/>
<xs:attribute name="norect" type="posDuration.datatype"/>
<xs:attribute name="spcmplt" type="posDuration.datatype"/>
<xs:attribute name="confidence">
<xs:simpleType>
<xs:restriction base="xs:positiveInteger">
<xs:maxInclusive value="100"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="sens" type="xs:positiveInteger"/>
<xs:attribute name="starttimer" type="boolean.datatype"
default="false"/>
<xs:attribute name="iterate" type="iterate.datatype"
default="1"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:element>
<xs:element name="tts" type="smediaType"
substitutionGroup="smedia"/>
</xs:schema>
Following is the schema for the MSML Fax packages (moml-fax-
module.xsd).
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified"
attributeFormDefault="unqualified">
<xs:include schemaLocation="moml-datatypes.xsd"/>
<xs:include schemaLocation="moml-core-module.xsd"/>
<xs:element name="faxdetect" substitutionGroup="primitive">
<xs:complexType>
<xs:choice>
<xs:group ref="sendType"/>
</xs:choice>
</xs:complexType>
Saleem & Sharratt Expires - August 2006 [Page 135]
Internet-draft Media Server Markup Language February 2006
(MSML)
</xs:element>
<xs:element name="faxsend" substitutionGroup="primitive">
<xs:complexType>
<xs:sequence>
<xs:element name="sendobj" type="sendobjType" minOccurs="0"
maxOccurs="unbounded"/>
<xs:element name="hdrfooter" type="hdrfooterType" minOccurs="0"/>
<xs:element name="rxpoll" minOccurs="0">
<xs:complexType>
<xs:sequence>
<xs:element name="rcvobj" type="rcvobjType"
maxOccurs="unbounded"/>
<xs:element name="hdrfooter" type="hdrfooterType"
minOccurs="0"/>
</xs:sequence>
<xs:attribute name="rmtid" type="faxid.datatype"
use="required"/>
</xs:complexType>
</xs:element>
<xs:group ref="faxstatusrequest"/>
</xs:sequence>
<xs:attribute name="lclid" type="faxid.datatype" use="optional"/>
<xs:attribute name="minspeed" type="faxspeed.datatype"
use="optional"/>
<xs:attribute name="maxspeed" type="faxspeed.datatype"
use="optional"/>
<xs:attribute name="ecm" type="boolean.datatype" use="optional"/>
</xs:complexType>
</xs:element>
<xs:element name="faxrecv" substitutionGroup="primitive">
<xs:complexType>
<xs:sequence>
<xs:element name="rcvobj" type="rcvobjType" minOccurs="0"
maxOccurs="unbounded"/>
<xs:element name="hdrfooter" type="hdrfooterType" minOccurs="0"/>
<xs:element name="txpoll" minOccurs="0">
<xs:complexType>
<xs:sequence>
<xs:element name="sendobj" type="sendobjType"
maxOccurs="unbounded"/>
<xs:element name="hdrfooter" type="hdrfooterType"
minOccurs="0"/>
</xs:sequence>
<xs:attribute name="rmtid" type="faxid.datatype"/>
</xs:complexType>
</xs:element>
<xs:group ref="faxstatusrequest"/>
</xs:sequence>
Saleem & Sharratt Expires - August 2006 [Page 136]
Internet-draft Media Server Markup Language February 2006
(MSML)
<xs:attribute name="lclid" type="faxid.datatype" use="optional"/>
<xs:attribute name="ecm" type="boolean.datatype" default="true"/>
</xs:complexType>
</xs:element>
<xs:group name="faxstatusrequest">
<xs:all>
<xs:element name="faxstart" minOccurs="0"/>
<xs:element name="faxnegotiate" minOccurs="0"/>
<xs:element name="faxpagedone" minOccurs="0"/>
<xs:element name="faxobjectdone" minOccurs="0"/>
<xs:element name="faxopcomplete" minOccurs="0"/>
<xs:element name="faxpollstart" minOccurs="0"/>
</xs:all>
</xs:group>
<xs:complexType name="hdrfooterType">
<xs:choice>
<xs:element name="format" type="xs:string" minOccurs="0"
maxOccurs="unbounded"/>
</xs:choice>
<xs:attribute name="type" type="hdrfooter.datatype"/>
<xs:attribute name="style" type="hdrfooterstyle.datatype"/>
</xs:complexType>
<xs:complexType name="formatType">
<xs:simpleContent>
<xs:extension base="xs:string">
<xs:attribute name="style">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="append"/>
<xs:enumeration value="overlay"/>
<xs:enumeration value="replace"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
<xs:complexType name="rcvobjType">
<xs:attribute name="objuri" type="xs:anyURI" use="required"/>
<xs:attribute name="maxpages" type="xs:positiveInteger"/>
</xs:complexType>
<xs:complexType name="sendobjType">
<xs:attribute name="objuri" type="xs:anyURI" use="required"/>
<xs:attribute name="startpage" type="xs:positiveInteger"/>
<xs:attribute name="pagecount" type="xs:positiveInteger"/>
</xs:complexType>
<xs:simpleType name="faxid.datatype">
<xs:restriction base="xs:string">
Saleem & Sharratt Expires - August 2006 [Page 137]
Internet-draft Media Server Markup Language February 2006
(MSML)
<xs:pattern value="[0-9+*- ]{20}"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="faxspeed.datatype">
<xs:restriction base="xs:string">
<xs:enumeration value="2400"/>
<xs:enumeration value="4800"/>
<xs:enumeration value="7200"/>
<xs:enumeration value="9600"/>
<xs:enumeration value="12000"/>
<xs:enumeration value="14400"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="hdrfooter.datatype">
<xs:restriction base="xs:string">
<xs:enumeration value="header"/>
<xs:enumeration value="footer"/>
<xs:enumeration value="autohdr"/>
<xs:enumeration value="nohdr"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="hdrfooterstyle.datatype">
<xs:restriction base="xs:string">
<xs:enumeration value="append"/>
<xs:enumeration value="overlay"/>
<xs:enumeration value="replace"/>
</xs:restriction>
</xs:simpleType>
</xs:schema>
18. Security Considerations
MSML is invoked through other languages and protocols and as such
security considerations depend on those environments.
MSML being an XML based language, security considerations as defined
by RFC 3023 [14] are applicable.
19. IANA Considerations
IANA registrations for ‘application/msml+xml’, ‘text/msml-basic-
layout’, and ‘application/moml+xml’ media types are planned.
MGCP and Megaco/H.248 packages are registered with IANA so that there
is no conflict between packages developed by different authors. The
package scheme planned for future extensibility of MSML will also
require IANA registry of packages.
Saleem & Sharratt Expires - August 2006 [Page 138]
Internet-draft Media Server Markup Language February 2006
(MSML)
20. URN Sub-Namespace Registration
The namespace URI for elements defined within this specification is a
URN [24]. It uses the namespace identifier 'ietf' defined by [25] and
extended by RFC 3688 [26]. The regisgtration of URN
(urn:ietf:params:xml:ns:msml) is planned.
21. XML Schema Registration
The XML schema associated with the MSML specification, is planned for
registration as per the guidelines in RFC 3688 [26].
22. References
[1] J. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J.
Peterson, R. Sparks, M. Handley, and E. Schooler, "SIP: Session
Initiation Protocol", RFC3261, Internet Engineering Taskforce, June
2002.
[2] J. Rosenberg, H. Schulzrinne, and P. Kyzivat, "Indicating User
Agent Capabilities in the Session Initiation Protocol (SIP)",
Internet Engineering Taskforce, December 2003. Work in progress.
[3] R. Mahy and N. Ismail, "Media Policy Manipulation in the
Conference Policy Control Protocol", Internet Draft, Internet
Engineering Taskforce, Feb. 2003. Work in progress.
[4] Bray, T., Paoli, J., Sperberg-McQueen, C., and E. Maler,
“Extensible Markup Language (XML) 1.0 (Second Edition),” W3C
FirstEdition REC-xml-20001006, October 2000.
[5] World Wide Web Consortium, "Speech Recognition Grammar
Specification Version 1.0" (SRGS), W3C Candidate Recommendation, June
26, 2002
[6] World Wide Web Consortium, "Natural Language Semantics Markup
Language (NLSML) for the Speech Interface Framework", W3C Working
Draft, May 2001.
[7] World Wide Web Consortium, "Voice Extensible Markup Language
(VoiceXML) Version 2.0, W3C Candidate Recommendation, February 20,
2003
[8] Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource
Identifiers (URI): Generic Syntax,” RFC 2396, August 1998.
Saleem & Sharratt Expires - August 2006 [Page 139]
Internet-draft Media Server Markup Language February 2006
(MSML)
[9] J. Van Dyke, E. Burger, A. Spitzer, "Basic Network Media Services
with SIP", Internet Draft, Internet Engineering Task Force, February
2005. Work in progress.
[10] C. Jennings, SIP Support for Application Initiation, Internet
Draft, Internet Engineering Taskforce, Oct. 2002. Work in progress.
[11] A. B. Roach, Session Initiation Protocol (SIP)-Specific Event
Notification, RFC 3265, Internet Engineering Taskforce, June 2002.
[12] E. Levinson, "Content-ID and Message-ID Uniform Resource
Locators", RFC 2392, Internet Engineering Taskforce, August 1998.
[13] S. Bradner, “Key words for use in RFCs to Indicate Requirement
Levels,” RFC 2119, Internet Engineering Taskforce, March 1997.
[14] M. Murata, S. St.Laurent, and D. Kohn, “XML Media Types,” RFC
3023, Internet Engineering Taskforce, January 2001.
[15] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson,
“RTP Profile for Audio and Video Conferences with Minimal Control,”
RFC 3550, July 2003.
[16] Rosenberg, J., Peterson, J., Schulzrinne, H., and G. Camarillo,
“Best Current Practices for Third Party Call Control (3pcc) in the
Session Initiation Protocol (SIP),” RFC 3725, April 2004.
[17] Donovan, S., “The SIP INFO Method,” RFC 2976, October 2000.
[18] Handley, M. and V. Jacobson, “SDP: Session Description
Protocol,” RFC 2327, April 1998.
[19] Ossenbruggen, J., Rutledge, L., Saccocio, B., Schmitz, P., Kate,
W., Ayars, J., Bulterman, D., Cohen, A., Day, K., Hodge, E., Hoschka,
P., Hyche, E., Jourdan, M., Kubota, K., Lanphier, R., Layaïda, N.,
Michel, T., and D. Newman, “Synchronized Multimedia Integration
Language (SMIL 2.0) Specification,” W3C REC REC-smil20-20010807,
August 2001.
[20] Bos, B., Lie, H., Lilley, C., and I. Jacobs, “Cascading Style
Sheets, level 2 (CSS2) Specification,” W3C REC REC-CSS2-19980512, May
1998.
[21] Freed, N. and N. Borenstein, “Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types,” RFC 2046, November 1996.
[22] Saleem, A. and Sharratt, G., “Media Sessions Markup Language”
Internet Draft (draft-melanchuk-sipping-msml-06), October 21, 2005.
Saleem & Sharratt Expires - August 2006 [Page 140]
Internet-draft Media Server Markup Language February 2006
(MSML)
[23] Saleem, A. and Sharratt, G., “Media Objects Markup Language”
Internet Draft (draft-melanchuk-sipping-moml-06), October 21, 2005.
[24] Moats, R., "URN Syntax", RFC 2141, May 1997.
[25] Moats, R., "A URN Namespace for IETF Documents", RFC 2648,
August 1999.
[26] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January
2004.
Acknowledgments
Yong Xin and Sergiu Stambolian of Convedia provided key insights,
both theoretic and through development experience, on several
versions of the drafts.
Stephen Buko and George Raskulinec of Intel made numerous valuable
contributions towards enhancements of multimedia playback and record
operations.
David Asher of NMS Communications provided valuable insights towards
creation of standard profiles and a modularization scheme based on
packages for better interoperability.
Gilles Compienne of Ubiquity Software has provided feedback on
several earlier versions of this draft.
Chris Boulton and Ben Smith, both of Ubiquity, and Michael Rice of
VocalData helped clarify several issues, while Bruce Walsh and Kevin
Fitzgerald, both of Spectel/Avaya, provided important feedback. Cliff
Schornak of Commetrex significantly contributed to the facsimile
work. Peter Danielsen of Lucent has contributed thoughtful and
detailed reviews for several earlier versions of the draft.
Authors' Addresses
Adnan Saleem
Convedia
4190 Still Creek Drive, Suite 300
Vancouver, BC, V5C 6C6
Canada
Phone: +1 604 918 6376
Email: asaleem@convedia.com
Saleem & Sharratt Expires - August 2006 [Page 141]
Internet-draft Media Server Markup Language February 2006
(MSML)
Garland Sharratt
Convedia
4190 Still Creek Drive, Suite 300
Vancouver, BC, V5C 6C6
Canada
Phone: +1 604 918 6393
Email: gsharratt@convedia.com
Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at ietf-
ipr@ietf.org.
Copyright Statement
Copyright (C) The Internet Society (2005). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights
Saleem & Sharratt Expires - August 2006 [Page 142]
Internet-draft Media Server Markup Language February 2006
(MSML)
Disclaimer of Validity
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
Saleem & Sharratt Expires - August 2006 [Page 143]