draft-ietf-mmusic-sdp-media-capabilities-07.txt   draft-ietf-mmusic-sdp-media-capabilities-08.txt 
MMUSIC R. Gilman MMUSIC R. Gilman
Internet-Draft NDCI Internet-Draft NDCI
Intended status: Standards Track R. Even Intended status: Standards Track R. Even
Expires: August 30, 2009 Gesher Erove Ltd Expires: January 11, 2010 Gesher Erove Ltd
F. Andreasen F. Andreasen
Cisco Systems Cisco Systems
February 26, 2009 July 10, 2009
SDP media capabilities Negotiation SDP media capabilities Negotiation
draft-ietf-mmusic-sdp-media-capabilities-07 draft-ietf-mmusic-sdp-media-capabilities-08
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
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Trust the right to allow modifications of such material outside the Trust the right to allow modifications of such material outside the
IETF Standards Process. Without obtaining an adequate license from IETF Standards Process. Without obtaining an adequate license from
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
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The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
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This Internet-Draft will expire on August 30, 2009. This Internet-Draft will expire on January 11, 2010.
Copyright Notice Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the Copyright (c) 2009 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents in effect on the date of Provisions Relating to IETF Documents in effect on the date of
publication of this document (http://trustee.ietf.org/license-info). publication of this document (http://trustee.ietf.org/license-info).
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
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3.3.6. Enhanced Potential Configuration Attribute . . . . . . 23 3.3.6. Enhanced Potential Configuration Attribute . . . . . . 23
3.3.7. Substitution of Media Payload Type Numbers in 3.3.7. Substitution of Media Payload Type Numbers in
Capability Attribute Parameters . . . . . . . . . . . 26 Capability Attribute Parameters . . . . . . . . . . . 26
3.3.8. The Session Capability Attribute . . . . . . . . . . . 28 3.3.8. The Session Capability Attribute . . . . . . . . . . . 28
3.4. Offer/Answer Model Extensions . . . . . . . . . . . . . . 32 3.4. Offer/Answer Model Extensions . . . . . . . . . . . . . . 32
3.4.1. Generating the Initial Offer . . . . . . . . . . . . . 32 3.4.1. Generating the Initial Offer . . . . . . . . . . . . . 32
3.4.2. Generating the Answer . . . . . . . . . . . . . . . . 33 3.4.2. Generating the Answer . . . . . . . . . . . . . . . . 33
3.4.3. Offerer Processing of the Answer . . . . . . . . . . . 33 3.4.3. Offerer Processing of the Answer . . . . . . . . . . . 33
3.4.4. Modifying the Session . . . . . . . . . . . . . . . . 33 3.4.4. Modifying the Session . . . . . . . . . . . . . . . . 33
4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
4.1. Alternative Codecs . . . . . . . . . . . . . . . . . . . . 34 4.1. a= . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
4.2. Alternative Combinations of Codecs (Session 4.2. Alternative Combinations of Codecs (Session
Configurations) . . . . . . . . . . . . . . . . . . . . . 37 Configurations) . . . . . . . . . . . . . . . . . . . . . 37
4.3. Latent Media Streams . . . . . . . . . . . . . . . . . . . 37 4.3. Latent Media Streams . . . . . . . . . . . . . . . . . . . 37
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 40 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 40
5.1. New SDP Attributes . . . . . . . . . . . . . . . . . . . . 40 5.1. New SDP Attributes . . . . . . . . . . . . . . . . . . . . 40
5.2. New SDP Option Tag . . . . . . . . . . . . . . . . . . . . 41 5.2. New SDP Option Tag . . . . . . . . . . . . . . . . . . . . 41
5.3. New SDP Capability Negotiation Parameters . . . . . . . . 41 5.3. New SDP Capability Negotiation Parameters . . . . . . . . 41
6. Security Considerations . . . . . . . . . . . . . . . . . . . 42 6. Security Considerations . . . . . . . . . . . . . . . . . . . 42
7. Changes from previous versions . . . . . . . . . . . . . . . . 43 7. Changes from previous versions . . . . . . . . . . . . . . . . 43
7.1. Changes from version 04 . . . . . . . . . . . . . . . . . 43 7.1. Changes from version 04 . . . . . . . . . . . . . . . . . 43
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media capability applies to the specific media description associated media capability applies to the specific media description associated
with the configuration which invokes it. with the configuration which invokes it.
For example: For example:
v=0 v=0
a=mcap:1 L16/8000/1 a=mcap:1 L16/8000/1
a=mcap:2 L16/16000/2 a=mcap:2 L16/16000/2
a=mcap:3,4 H263-1998/90000 a=mcap:3,4 H263-1998/90000
m=audio 54320 RTP/AVP 0 m=audio 54320 RTP/AVP 0
pcfg:1 m=1|2, pt=1:99,2:98 a=pcfg:1 m=1|2, pt=1:99,2:98
m=video 66544 RTP/AVP 100 m=video 66544 RTP/AVP 100
a=rtpmap:100 H264/90000 a=rtpmap:100 H264/90000
a=pcfg:10 m=3 pt=3:101 a=pcfg:10 m=3 pt=3:101
3.3.2. The Media Format Parameter Capability Attribute 3.3.2. The Media Format Parameter Capability Attribute
This attribute is used to associate media-specific format parameters This attribute is used to associate media-specific format parameters
with one or more media capabilities. The form of the attribute is: with one or more media capabilities. The form of the attribute is:
a=mfcap:<media-caps> <list of parameters> a=mfcap:<media-caps> <list of parameters>
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Alternatively, the initiator may perform a new capabilities exchange Alternatively, the initiator may perform a new capabilities exchange
as part of the reconfiguration. In such a case, the new capabilities as part of the reconfiguration. In such a case, the new capabilities
will replace the previously-negotiated capabilities. This may be will replace the previously-negotiated capabilities. This may be
useful if conditions change on the endpoint. useful if conditions change on the endpoint.
4. Examples 4. Examples
In this section, we provide examples showing how to use the Media In this section, we provide examples showing how to use the Media
Capabilities with the SDP Capability Negotiation. Capabilities with the SDP Capability Negotiation.
4.1. Alternative Codecs 4.1. a=
This example provide a choice of one of six variations of the This example provide a choice of one of six variations of the
adaptive multirate codec. In this example, the default configuration adaptive multirate codec. In this example, the default configuration
as specified by the media line is the same as the most preferred as specified by the media line is the same as the most preferred
configuration. Each configuration uses a different payload type configuration. Each configuration uses a different payload type
number so the offeror can interpret early media. number so the offeror can interpret early media.
1. v=0 1. v=0
2. o=- 25678 753849 IN IP4 192.0.2.1 2. o=- 25678 753849 IN IP4 192.0.2.1
3. s= 3. s=
4. c=IN IP4 192.0.2.1 4. c=IN IP4 192.0.2.1
5. t=0 0 5. t=0 0
6. a=creq:med-v0 6. a=creq:med-v0
7. m=audio 54322 RTP/AVP 96 7. m=audio 54322 RTP/AVP 96
8. rtpmap:96 AMR-WB/16000/1 8. rtpmap:96 AMR-WB/16000/1
9. a=fmtp:96 mode-change-capability=1; max-red=220; mode- 9. a=fmtp:96 mode-change-capability=1; max-red=220; mode-
set=0,2,4,7 set=0,2,4,7
10. a=macp:1,3,5 audio AMR-WB/16000/1 10. a=mcap:1,3,5 audio AMR-WB/16000/1
11. a=mcap:2,4,6 audio AMR/8000/1 11. a=mcap:2,4,6 audio AMR/8000/1
12. a=mfcap:1,2,3,4 mode-change-capability=1 12. a=mfcap:1,2,3,4 mode-change-capability=1
13. a=mfcap:5,6 mode-change-capability=2 13. a=mfcap:5,6 mode-change-capability=2
14. a=mfcap:1,2,3,5 max-red=220 14. a=mfcap:1,2,3,5 max-red=220
15. a=mfcap:3,4,5,6 octet-align=1 15. a=mfcap:3,4,5,6 octet-align=1
16. a=mfcap:1,3,5 mode-set=0,2,4,7 16. a=mfcap:1,3,5 mode-set=0,2,4,7
17. a=mfcap:2,4,6 mode-set=0,3,5,6 17. a=mfcap:2,4,6 mode-set=0,3,5,6
18. pcfg:1 m=1 pt=1:96 18. a=pcfg:1 m=1 pt=1:96
19. pcfg:2 m=2 pt=2:97 19. a=pcfg:2 m=2 pt=2:97
20. pcfg:3 m=3 pt=3:98 20. a=pcfg:3 m=3 pt=3:98
21. pcfg:4 m=4 pt=4:99 21. a=pcfg:4 m=4 pt=4:99
22. pcfg:5 m=5 pt=5:100 22. a=pcfg:5 m=5 pt=5:100
23. pcfg:6 m=6 pt=6:101 23. a=pcfg:6 m=6 pt=6:101
In the above example, media capability 1 could have been excluded In the above example, media capability 1 could have been excluded
from the mcap declaration in line 10 and from the mfcap attributes in from the mcap declaration in line 10 and from the mfcap attributes in
lines 12, 14, and 16. The pcfg on line 18 could then have been lines 12, 14, and 16. The pcfg on line 18 could then have been
simply "pcfg:1". simply "pcfg:1".
The next example offers a video stream with three options of H.264 The next example offers a video stream with three options of H.264
and 4 transports. It also includes an audio stream with different and 4 transports. It also includes an audio stream with different
audio qualities: four variations of AMR, or AC3. The offer looks audio qualities: four variations of AMR, or AC3. The offer looks
something like: something like:
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