[FFmpeg-devel] RTP mark bit not passed to parse_packet

Luca Abeni lucabe72
Thu Jan 15 23:05:18 CET 2009

Hi Alexandre,

sorry for not replying to the previous emails: I've been offline for 
some time :)
Anyway, I see that you already solved most of the problems.

> Further investigation (printing the incremented counter of frames in 
> av_find_stream_info()) shows that it takes a fairly large number of 
> frames to decide, unless an EOF occurs I guess. But in RTP/UDP there's 
> no EOF of course, and I was repeatedly streaming the same short 
> sequence, so when the seqnum/timestamps had a discontinuity, maybe the 
> guessing work was reset...
> Anyway, streaming a longer sequence works.
> A few ancillary questions:
> 1) This means all those frames are accumulated in memory, right ?
> 2) What extra info could I have provided (eithr in the SDP or in 
> command-line options) so that this guessing work be avoided ?

I do not know the H.263-related RFCs, but mpeg4 and H.264 allow encoding 
the video "global headers" in the SDP (in the "config" tag for mpeg4 or 
in the "sprop-parameters-set" tag for H.264). If H.263 allows something 
similar (you have to check the RFC) then this kind of out-of-band global 
headers should provide all the needed information to 
av_find_stream_info() (the SDP parser will have to put this information 
in the extradata field of the AVCodecContext).


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