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I'm trying to understand how RFC3984 works with RFC3550.

I noticed that there is an extension bit in RFC3550 that you can set to extend the header. Do I need to set this bit high and then include the optional header extension? Would this be done by setting the "defined by profile" to be 3984, setting the length to the size of the appropriate 3984 header, and then including the header information from RFC3984 as the header extension?

If not, do I just append the RFC3984 appropriate header immediately after the RFC3550 header while leaving the extension bit 0?

Shaun
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1 Answers1

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RFC 3984 specifies an RTP payload format for h.264 data. This format goes in the payload section of an RTP packet, which follows the RTP header defined in RFC 3550. Section 5 of RFC 3984 shows how the RTP header and payload are constructed to create the full packet.

The payload type field of the RTP header actually communicates what the RTP payload format is. For h.264 data, there is no statically allocated payload type, but instead a dynamic type is used. Dynamic types are mapped to the underlying format through out-of-band communication. With RTSP, this mapping is communicated through the SDP (Session Description Protocol) message.

See Section 5.3.1 of RFC 3550 for usage of the Extension bit, but it should not be needed for using the payload format specified in RFC 3984.

Community
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Joel Cunningham
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