H.264 Packetization Mode

In SIP, the packetization-mode parameter signals the properties of the RTP payload type or the capabilities of a receiver’s implementation. Only a single configuration point can be indicated. So when capabilities support more than one packetization-mode are declared, multiple configuration points (RTP payload types) must be used.

• When the value of packetization-mode equals 0 or packetization-mode is not present, the single NAL mode is used.
• When the value of packetization-mode equals 1, the non- interleaved mode is used.
• When the value of packetization-mode equals 2, the interleaved mode is used.

This example shows a SIP offer-answer exchange. Here is the offer SDP:

m=video 49170 RTP/AVP 100 99 98
a=rtpmap:98 H264/90000
a=fmtp:98 profile-level-id=42A01E; packetization-mode=0;
a=rtpmap:99 H264/90000
a=fmtp:99 profile-level-id=42A01E; packetization-mode=1;
a=rtpmap:100 H264/90000
a=fmtp:100 profile-level-id=42A01E; packetization-mode=2;

And here is the answer SDP for the example:

m=video 49170 RTP/AVP 100 99 97
a=rtpmap:97 H264/90000
a=fmtp:97 profile-level-id=42A01E; packetization-mode=0;
a=rtpmap:99 H264/90000
a=fmtp:99 profile-level-id=42A01E; packetization-mode=1;
a=rtpmap:100 H264/90000
a=fmtp:100 profile-level-id=42A01E; packetization-mode=2;