[FFmpeg-devel] H.263 packetizing into RTP

Yohann Martineau yohann.martineau
Fri Apr 3 21:45:24 CEST 2009

Martin Storsj? a ?crit :
> On Fri, 3 Apr 2009, Yohann Martineau wrote:
>> On 4/3/09, Michael Niedermayer <michaelni at gmx.at> wrote:
>>> also i suspect that packets should be split at slices/gobs
>> RFC 2190 states that pictures should be split either at gob level
>> (mode A), at MB boundaries (mode B) or at MB boundaires of P-frames
>> with PB-frame mode.
> As far as I know (I found the original patch in a mailing list post from 
> Luca Abeni), this is an implementation of RFC 4629 (and 2429); this is a 
> different RTP packetization scheme than the one in RFC 2190. As of RFC 
> 4629, this is the recommended scheme for all variants of H.263.
> In this packetization scheme, the frame can be split into packets 
> regardless of GOB/MB boundaries or anything else. From RFC 4629, section 
> 6.2:
>    A Follow-on Packet contains a number of bytes of coded H.263+ data
>    that do not start at a synchronization point.  That is, a Follow-on
>    Packet does not start with a Picture, GOB, Slice, EOS, or EOSBS
>    header, and it may or may not start at a macroblock boundary.

ok, how do you test this patch? Most of the network traces of video 
calls I've seen in SIP networks use GBSC for I-Frames.

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