mirror of
https://github.com/moparisthebest/xeps
synced 2024-11-27 11:42:17 -05:00
175 lines
7.5 KiB
XML
175 lines
7.5 KiB
XML
<?xml version='1.0' encoding='UTF-8'?>
|
|
<!DOCTYPE xep SYSTEM 'xep.dtd' [
|
|
<!ENTITY % ents SYSTEM 'xep.ent'>
|
|
%ents;
|
|
]>
|
|
<?xml-stylesheet type='text/xsl' href='xep.xsl'?>
|
|
<xep>
|
|
<header>
|
|
<title>Source-Specific Media Attributes in Jingle</title>
|
|
<abstract>This specification provides an XML mapping for translating the RFC 5766 Source-Specific Media Attributes from SDP to Jingle</abstract>
|
|
&LEGALNOTICE;
|
|
<number>0339</number>
|
|
<status>Experimental</status>
|
|
<type>Standards Track</type>
|
|
<sig>Standards</sig>
|
|
<approver>Council</approver>
|
|
<dependencies>
|
|
<spec>XEP-0166</spec>
|
|
</dependencies>
|
|
<supersedes/>
|
|
<supersededby/>
|
|
<shortname>NOT_YET_ASSIGNED</shortname>
|
|
&fippo;
|
|
<revision>
|
|
<version>0.2</version>
|
|
<date>2015-11-09</date>
|
|
<initials>ph</initials>
|
|
<remark><p>remove obsolete mslabel and label lines.</p></remark>
|
|
</revision>
|
|
<revision>
|
|
<version>0.1</version>
|
|
<date>2014-01-08</date>
|
|
<initials>psa</initials>
|
|
<remark><p>Initial published version approved by the XMPP Council.</p></remark>
|
|
</revision>
|
|
<revision>
|
|
<version>0.0.1</version>
|
|
<date>2013-11-25</date>
|
|
<initials>ph</initials>
|
|
<remark><p>First draft.</p></remark>
|
|
</revision>
|
|
</header>
|
|
<section1 topic="Introduction" anchor="intro">
|
|
<p>&rfc5576; provides a mechanism to describe attributes of individual media sources (identified by their synchronization source) within a media stream. A mapping to Jingle as an extension to &xep0167; is defined in this document.</p>
|
|
</section1>
|
|
<section1 topic='Mapping to Session Description Protocol' anchor='sdp'>
|
|
<section2 topic='The ssrc attribute' anchor='sdp-ssrc'>
|
|
<p>The SDP format defined in <cite>RFC 5576</cite> is shown below.</p>
|
|
<code>
|
|
a=ssrc:<ssrc-id> <attribute>
|
|
a=ssrc:<ssrc-id> <attribute>:<value>
|
|
</code>
|
|
<p>This maps to Jingle as a <source/> element qualified by the 'urn:xmpp:jingle:apps:rtp:ssma:0' namespace. Since 'ssrc' is a media attribute in SDP, the <source/> element is included as child of the Jingle <description/> element.</p>
|
|
<code><![CDATA[
|
|
<source ssrc='ssrc-id' xmlns='urn:xmpp:jingle:apps:rtp:ssma:0'>
|
|
<parameter name='attribute'/>
|
|
<parameter name='attribute' value='value'/>
|
|
</source>
|
|
]]></code>
|
|
<p>Each ssrc-id maps to a <source/> element whose 'ssrc' attribute is set to the ssrc-id. The associated attributes map to <parameter/> children with 'name' and 'value' attributes. If there is no value in the SDP, the value parameter shall be omitted.</p>
|
|
<p>An example follows:</p>
|
|
<code>
|
|
a=ssrc:1656081975 cname:Yv/wvbCdsDW2Prgd
|
|
a=ssrc:1656081975 msid:MLTJKIHilGn71fNQoszkQ4jlPTuS5vJyKVIv MLTJKIHilGn71fNQoszkQ4jlPTuS5vJyKVIva0</code>
|
|
<code><![CDATA[
|
|
<source ssrc='1656081975' xmlns='urn:xmpp:jingle:apps:rtp:ssma:0'>
|
|
<parameter name='cname' value='Yv/wvbCdsDW2Prgd'/>
|
|
<parameter name='msid' value='MLTJKIHilGn71fNQoszkQ4jlPTuS5vJyKVIv MLTJKIHilGn71fNQoszkQ4jlPTuS5vJyKVIva0'/>
|
|
</source>]]></code>
|
|
</section2>
|
|
<section2 topic='The ssrc-group attribute' anchor='sdp-ssrc-group'>
|
|
<p>The SDP format defined in <cite>RFC 5576</cite> is shown below.</p>
|
|
<code>
|
|
a=ssrc-group:<semantics> <ssrc-id> ...</code>
|
|
<p>This maps to Jingle as a <ssrc-group/> element qualified by the 'urn:xmpp:jingle:apps:rtp:ssma:0' namespace. Like the <source/> element, this is included as child of the Jingle <description/> element. The SDP 'semantics' parameter is mapped to the semantics attribute (for consistency with &xep0338;) and the list of ssrc-ids is mapped to <source/> elements whole 'ssrc' attribute is set to the ssrc-id.</p>
|
|
<code><![CDATA[
|
|
<ssrc-group xmlns='urn:xmpp:jingle:apps:rtp:ssma:0' semantics='semantics'>
|
|
<source ssrc='ssrc-id'/>
|
|
[...]
|
|
</ssrc-group>]]></code>
|
|
</section2>
|
|
</section1>
|
|
<section1 topic='Example' anchor='example'>
|
|
<p>A minimal example follows:</p>
|
|
<code>
|
|
m=video 1 RTP/SAVPF 100 116 117
|
|
a=rtpmap:100 VP8/90000
|
|
a=ssrc-group:FID 2301230316 386328120
|
|
a=ssrc:2301230316 cname:T5qvrIZj42v//eYQ
|
|
a=ssrc:386328120 cname:uEYgNtStZyTF74sM
|
|
a=ssrc-group:FID 3139499595 2613715171
|
|
a=ssrc:3139499595 cname:re8jhxkly9bxzuxr
|
|
a=ssrc:2613715171 cname:f83avsiw6n1m7vi
|
|
</code>
|
|
<p>This is mapped to Jingle as follows:</p>
|
|
<code><![CDATA[
|
|
<content creator='initiator' name='webcam'>
|
|
<description xmlns='urn:xmpp:jingle:apps:rtp:1' media='video'>
|
|
<payload-type id='100' name='VP8' clockrate='90000'/>
|
|
<ssrc-group xmlns='urn:xmpp:jingle:apps:rtp:ssma:0' semantics='FID'>
|
|
<source ssrc='2301230316'/>
|
|
<source ssrc='386328120'/>
|
|
</ssrc-group>
|
|
<ssrc-group xmlns='urn:xmpp:jingle:apps:rtp:ssma:0' semantics='FID'>
|
|
<source ssrc='3139499595'/>
|
|
<source ssrc='2613715171'/>
|
|
</ssrc-group>
|
|
<source ssrc='2301230316' xmlns='urn:xmpp:jingle:apps:rtp:ssma:0'>
|
|
<parameter name='cname' value='T5qvrIZj42v//eYQ'/>
|
|
</source>
|
|
<source ssrc='386328120' xmlns='urn:xmpp:jingle:apps:rtp:ssma:0'>
|
|
<parameter name='cname' value='uEYgNtStZyTF74sM'/>
|
|
</source>
|
|
<source ssrc='3139499595' xmlns='urn:xmpp:jingle:apps:rtp:ssma:0'>
|
|
<parameter name='cname' value='re8jhxkly9bxzuxr'/>
|
|
</source>
|
|
<source ssrc='2613715171' xmlns='urn:xmpp:jingle:apps:rtp:ssma:0'>
|
|
<parameter name='cname' value='f83avsiw6n1m7vi'/>
|
|
</source>
|
|
</description>
|
|
</content>
|
|
]]></code>
|
|
</section1>
|
|
<section1 topic='Determining Support' anchor='disco'>
|
|
<p>If an entity supports source specific media attributes as described in <cite>RFC 5576</cite>, it MUST advertise that fact in its responses to &xep0030; information ("disco#info") requests by returning a feature of 'urn:ietf:rfc:5576':</p>
|
|
<example caption='A disco#info query'><![CDATA[
|
|
<iq type='get'
|
|
from='calvin@usrobots.lit/lab'
|
|
to='herbie@usrobots.lit/home'
|
|
id='disco1'>
|
|
<query xmlns='http://jabber.org/protocol/disco#info'/>
|
|
</iq>
|
|
]]></example>
|
|
<example caption='A disco#info response'><![CDATA[
|
|
<iq type='result'
|
|
from='herbie@usrobots.lit/home'
|
|
to='calvin@usrobots.lit/lab'
|
|
id='disco1'>
|
|
<query xmlns='http://jabber.org/protocol/disco#info'>
|
|
<feature var='urn:xmpp:jingle:1'/>
|
|
<feature var='urn:ietf:rfc:5576'/>
|
|
</query>
|
|
</iq>
|
|
]]></example>
|
|
<p>In order for an application to determine whether an entity supports this protocol, where possible it SHOULD use the dynamic, presence-based profile of service discovery defined in &xep0115;. However, if an application has not received entity capabilities information from an entity, it SHOULD use explicit service discovery instead.</p>
|
|
</section1>
|
|
<!--
|
|
<section1 topic='Acknowledgements' anchor='acks'>
|
|
</section1>
|
|
-->
|
|
<section1 topic='Security Considerations' anchor='security'>
|
|
<p>This document introduces no additional security considerations above and beyond those defined in the documents on which it depends.</p>
|
|
</section1>
|
|
|
|
<section1 topic='IANA Considerations' anchor='iana'>
|
|
<p>This document requires no interaction with &IANA;.</p>
|
|
</section1>
|
|
|
|
<section1 topic='XMPP Registrar Considerations' anchor='registrar'>
|
|
<section2 topic='Protocol Namespaces' anchor='registrar-ns'>
|
|
<p>This specification defines the following XML namespace:</p>
|
|
<ul>
|
|
<li>urn:xmpp:jingle:apps:rtp:ssma:0</li>
|
|
</ul>
|
|
<p>The ®ISTRAR; includes the foregoing namespace to the registry located at &NAMESPACES;, as described in Section 4 of &xep0053;.</p>
|
|
</section2>
|
|
<section2 topic='Protocol Versioning' anchor='registrar-versioning'>
|
|
&NSVER;
|
|
</section2>
|
|
</section1>
|
|
<section1 topic='XML Schema' anchor='schema'>
|
|
<p>TODO</p>
|
|
</section1>
|
|
</xep>
|