A.11 Adding or removing a video component to/from an on-going video call session
26.1143GPPIP Multimedia Subsystem (IMS)Media handling and interactionMultimedia telephonyRelease 18TS
The MTSI client in a terminal can add, remove and modify the media components during an ongoing MTSI session. This clause describes the SDP offer in the initial SIP INVITE message, see Table A.11.1, and the SDP in the subsequent re-INVITE or UPDATE message for adding and removing a video stream to/from the ongoing MTSI video call session, see Table A.11.2 and Table A.11.3, respectively. Corresponding SDP answers in the SIP 200/OK responses are also described.
The initial video call session contains one video component and one speech component. During the session, the MTSI client in terminal A adds a uni-directional video component (such as one video clip) to the ongoing video call session. The SDP content attribute "a=content:main" and "a=content:alt" are used to label the main and alternative video components respectively [81].
This example does not show how to use the content attribute in combination with the grouping attribute, nor does it show how to use the content attribute in combination with the synchronization attribute defined in Clause 6.2.6.
Table A.11.1: SDP offer/answer for setting up a video telephony session
|
SDP offer from MTSI client in terminal A to B in SIP INVITE message |
|
a=tcap:1 RTP/AVPF m=audio 49150 RTP/AVP 96 a=pcfg:1 t=1 b=AS:29 b=RS:0 b=RR:2000 a=rtpmap:96 AMR/8000/1 a=fmtp:96 mode-change-capability=2; max-red=220 a=ptime:20 a=maxptime:240 m=video 54320 RTP/AVP 99 a=pcfg:1 t=1 b=AS:315 b=RS:0 b=RR:2500 a=rtpmap:99 H264/90000 a=fmtp:99 packetization-mode=0; profile-level-id=42e00c; \ sprop-parameter-sets=J0LgDJWgUH6Af1A=,KM46gA== a=rtcp-fb:* trr-int 5000 a=rtcp-fb:* nack a=rtcp-fb:* nack pli a=rtcp-fb:* ccm fir a=rtcp-fb:* ccm tmmbr a=extmap:4 urn:3gpp:video-orientation |
|
SDP answer from MTSI client in terminal B to A in 200/OK RESPONSE message |
|
m=audio 49152 RTP/AVPF 96 a=acfg:1 t=1 b=AS:29 b=RS:0 b=RR:2000 a=rtpmap:96 AMR/8000/1 a=fmtp:96 mode-change-capability=2; max-red=220 a=ptime:20 a=maxptime:240 m=video 54320 RTP/AVPF 99 a=acfg:1 t=1 b=AS:315 b=RS:0 b=RR:2500 a=rtpmap:99 H264/90000 a=fmtp:99 packetization-mode=0; profile-level-id=42e00c; \ sprop-parameter-sets=J0LgDJWgUH6Af1A=,KM46gA== a=rtcp-fb:* trr-int 5000 a=rtcp-fb:* nack a=rtcp-fb:* nack pli a=rtcp-fb:* ccm fir a=rtcp-fb:* ccm tmmbr a=extmap:4 urn:3gpp:video-orientation |
Table A.11.2: Second SDP offer/answer for adding one more video component
|
SDP offer from MTSI client in terminal A to B in SIP UPDATE/Re-INVITE message |
|
a=tcap:1 RTP/AVPF m=audio 49150 RTP/AVP 96 a=pcfg:1 t=1 b=AS:29 b=RS:0 b=RR:2000 a=rtpmap:96 AMR/8000/1 a=fmtp:96 mode-change-capability=2; max-red=220 a=ptime:20 a=maxptime:240 m=video 54320 RTP/AVP 99 i=Main video a=pcfg:1 t=1 b=AS:315 b=RS:0 b=RR:2500 a=rtpmap:99 H264/90000 a=fmtp:99 packetization-mode=0; profile-level-id=42e00c; \ sprop-parameter-sets=J0LgDJWgUH6Af1A=,KM46gA== a=rtcp-fb:* trr-int 5000 a=rtcp-fb:* nack a=rtcp-fb:* nack pli a=rtcp-fb:* ccm fir a=rtcp-fb:* ccm tmmbr a=content:main a=extmap:4 urn:3gpp:video-orientation m=video 43200 RTP/AVP 100 i=Alternative video a=pcfg:1 t=1 b=AS:128 b=RS:0 b=RR:2500 a=rtpmap:100 H264/90000 a=fmtp:100 packetization-mode=0; profile-level-id=42e00c; \ sprop-parameter-sets=J0LgDJWgUH6Af1A=,KM46gA== a=content:alt a=sendonly a=extmap:4 urn:3gpp:video-orientation |
|
SDP answer from MTSI client in terminal B to A in 200/OK RESPONSE to UPDATE/Re-INVITE message |
|
m=audio 49152 RTP/AVPF 96 a=acfg:1 t=1 b=AS:29 b=RS:0 b=RR:2000 a=rtpmap:96 AMR/8000/1 a=fmtp:96 mode-change-capability=2; max-red=220 a=ptime:20 a=maxptime:240 m=video 54320 RTP/AVPF 99 a=acfg:1 t=1 b=AS:315 b=RS:0 b=RR:2500 a=rtpmap:99 H264/90000 a=fmtp:99 packetization-mode=0; profile-level-id=42e00c; \ sprop-parameter-sets=J0LgDJWgUH6Af1A=,KM46gA== a=rtcp-fb:* trr-int 5000 a=rtcp-fb:* nack a=rtcp-fb:* nack pli a=rtcp-fb:* ccm fir a=rtcp-fb:* ccm tmmbr a=content:main a=extmap:4 urn:3gpp:video-orientation m=video 43200 RTP/AVPF 100 a=acfg:1 t=1 b=AS:128 b=RS:0 b=RR:2500 a=rtpmap:100 H264/90000 a=fmtp:100 packetization-mode=0; profile-level-id=42e00c; \ sprop-parameter-sets=J0LgDJWgUH6Af1A=,KM46gA== a=content:alt a=recvonly a=extmap:4 urn:3gpp:video-orientation |
Table A.11.3: Second SDP offer/answer for removing the video component
|
SDP offer from MTSI client in terminal A to B in SIP INVITE message |
|
m=audio 49150 RTP/AVPF 96 b=AS:29 b=RS:0 b=RR:2000 a=rtpmap:96 AMR/8000/1 a=fmtp:96 mode-change-capability=2; max-red=220 a=ptime:20 a=maxptime:240 m=video 0 RTP/AVP 99 |
|
SDP answer from MTSI client in terminal B to A in 200/OK RESPONSE message |
|
m=audio 49152 RTP/AVPF 96 b=AS:29 b=RS:0 b=RR:2000 a=rtpmap:96 AMR/8000/1 a=fmtp:96 mode-change-capability=2; max-red=220 a=ptime:20 a=maxptime:240 m=video 0 RTP/AVP 99 |