[Ffmpeg-devel] PTS / DTS with XViD

Jani Boutellier janib
Sun Jul 23 07:29:38 CEST 2006

M?ns Rullg?rd wrote:
> Rich Felker said:
>>On Fri, Jul 21, 2006 at 08:01:13PM +0300, Jani Boutellier wrote:
>>>As a concluding remark, I'll have to state that the problem was not at all
>>>in the OGM format.
>>>After hours of trial and error I managed to get the XViD-encoded video into
>>>a MPEG4 -container (.mp4). Surprisingly the the abovementioned problem with
>>>OGM occurred also with mp4, so I figured that the true source of problems
>>>was XViD.
>>>Soon I discovered that the video clips I had used, contained a so-called
>>>"packed bitstream", which meant that the B-frames were crammed inside
>>>P-frames. After I changed this in encoding settings and re-encoded the
>>>video clips, the decoding worked well.
>>Did ffmpeg generate these bitstreams? I sure hope it's not calling
>>xvid with packed bitstream enabled...
> FFmeg doesn't mux OGM so it can't have made those files.
>>>This means that although the OGM format was labeled as a "broken format" in
>>>this thread, it probably would work well also with b-frames. However, I
>>>didn't try that in practice anymore, since I'm happy with mp4 now :)
>>I imagine the timestamps would still be invalid but I'm not sure..
> Ogg only has frame count, no real timestamps.
I created the clips by packing Xvid inside AVI-files with VirtualDub and 
then used FFMPEG by '-vcodec copy' to move the xvid stream from avi to 
mp4. This applied to both to packed and normal bitstreams.

Jani Boutellier

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