[Ffmpeg-devel] [Ffmpeg-devel-old] rtp mpeg4 packetize problem

Zoltan NAGY nagyz
Thu Jul 21 09:40:47 CEST 2005

Luca Abeni wrote:

>On Wed, 2005-07-20 at 12:57 +0200, Zoltan NAGY wrote:
>>after av_read_frame(), split the frame into packets, put the rtp header 
>>on them, and send them over the network.
>>it sounds very simple, but.. does it work? :)
>Yes, it can work... Provided that you properly fill the RTP header :)
what fields must I set correctly?
currently, I set version to 2, padding to 0, extension to 0,
csrc_count to 0, I set the marker bit on the last packet
in every frame to 1 (otherwise 0), and the sequence number.

however, when I try to play it with ffplay (after generating the correct
sdp file, that contains the extradata and everything):
plazma3:~# ffplay file.sdp
[NULL @ 0xb7efcbe8]RTP: PT=60: bad cseq 0100 expected=0001
[mpeg4 @ 0xb7efcbe8]warning: first frame is no keyframe
[mpeg4 @ 0xb7efcbe8]Error at MB: 394
[mpeg4 @ 0xb7efcbe8]marker does not match f_code
[mpeg4 @ 0xb7efcbe8]marker does not match f_code
[mpeg4 @ 0xb7efcbe8]marker does not match f_code
[mpeg4 @ 0xb7efcbe8]concealing 864 DC, 864 AC, 864 MV errors
[mpeg4 @ 0xb7efcbe8]cbpc damaged at 24 9
[mpeg4 @ 0xb7efcbe8]Error at MB: 393
[mpeg4 @ 0xb7efcbe8]illegal dc vlc
[mpeg4 @ 0xb7efcbe8]Error at MB: 270
[mpeg4 @ 0xb7efcbe8]marker does not match f_code

etc, etc..

what does this "marker does not match f_code" error means?
what does the concealing error messages means?
what other fields must I set correctly in order to be able to play back
my stream with ffmpeg correctly?

Thanks in advance,

Zoltan NAGY,
Software Engineer

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