[FFmpeg-devel] Patch for "non monotone timestamp" error

Diep Ho DHo
Fri Aug 1 17:47:44 CEST 2008

> -----Original Message-----
> From: ffmpeg-devel-bounces at mplayerhq.hu [mailto:ffmpeg-devel-
> bounces at mplayerhq.hu] On Behalf Of Michael Niedermayer
> Sent: vendredi 1 ao?t 2008 11:50
> To: FFmpeg development discussions and patches
> Subject: Re: [FFmpeg-devel] Patch for "non monotone timestamp" error
> On Fri, Aug 01, 2008 at 09:43:33AM +0200, Diep Ho wrote:
> > Sorry for hijacking a topic. I'm  new.
> >
> >
> >
> > I reiterate this topic because I still do not understand why the
> patch
> > is rejected. Was the old code try to detect a b-frame? If yes, this
> > should be patched.
> The code you change was correct before your patch and is totally broken
> after your patch, the patch is rejected.

Thank you for the reply. But this is a bad news for us. 

I want to draw your attention to our situation: Our files are encoded with mpeg1video and CODEC_FLAG_LOW_DELAY hence does not have any b-frames. And I find in libavformat/utils.c:790 (compute_pkt_fields) 

Delay = st->codec->has_b_frames 

that is dependent on MpegEncContext->low_delay. This variable is read in the sequence_extension_data which is not available in MPEG1, I think (am I right??). Hence low_delay is always 0. As a consequence, has_b_frames and delay above are TRUE. That might be why I had the "non monotone timestamps" error. 

If the flag low_delay were correctly set, there would not be any problem.

Have you any idea of how to fix this in FFMPEG? 

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