This documents specifies how to negotiate the use of the RTP - Header Extensions as defined by &rfc5285; with Jingle RTP + Header Extensions as defined by &rfc5285; and &rfc8285; with Jingle RTP sessions.
The Jingle extension defined herein is designed to meet the following requirements:
This specification defines a new element, <rtp-hdrext/>, that can be inserted in the <description/> element of a XEP-0167 RTP session.
-The attributes of the <rtp-hdrext/> element are:
-| Attribute | -Description | -Inclusion | -Possible values | -
|---|---|---|---|
| id | -The ID of the extensions | -REQUIRED | -1-256, 4096-4351 | -
| uri | -The URI that defines the extension | -REQUIRED | -Any valid URI | -
| senders | -Which party is allowed to send the negotiated RTP Header Extensions | -OPTIONAL (defaults to "both") | -"initiator", "responder", and "both" | -
Any type of RTP Header Extension that requires extra -parameters in the a=b form can embed <parameter/> elements to -describe it. Any other form of parameter can be stored as the 'key' attribute in a parameter element with an empty value.
+The attributes of the <rtp-hdrext/> element are:
+| Attribute | +Description | +Inclusion | +Possible values | +
|---|---|---|---|
| id | +The ID of the extensions | +REQUIRED | +1-256, 4096-4351 | +
| uri | +The URI that defines the extension | +REQUIRED | +Any valid URI | +
| senders | +Which party is allowed to send the negotiated RTP Header Extensions | +OPTIONAL (defaults to "both") | +"initiator", "responder", and "both" | +
Any type of RTP Header Extension that requires extra + parameters in the a=b form can embed <parameter/> elements to + describe it. Any other form of parameter can be stored as the 'key' attribute in a parameter element with an empty value.
+ +This specification defines a new element, <extmap-allow-mixed/>, + that can be inserted in the <description/> element of a + XEP-0167 RTP session. The element has no attributes.
The usage of the <extmap-allow-mixed/> is governed by the + SDP Offer/Answer mechanism as well.
+Example negotiation where the initiator offers to use the
timestamp offset header extension as defined in &rfc5450; and also
the requests synchronisation metadata header extension (&rfc6051;)
@@ -150,11 +158,13 @@ describe it. Any other form of parameter can be stored as the 'key' attribute in
uri='urn:ietf:params:rtp-hdrext:ntp-56'
id='4907'/>
Example reply where the responder accepts the timestamp offset - and the 56-bit synchronisation metadata header extensions.
+ and the 56-bit synchronisation metadata header extensions as well as the + <extmap-allow-mixed/>.The <extmap-allow-mixed/> element maps to the "a=extmap-allow-mixed" SDP line + defined in RFC 8285. Note that a session-level line might need to be mapped + to all <description/> elements.
+Example conversion of a incomplete sample fragment of a SDP taken from RFC 5285 section 6 into equivalent XMPP: