[Ffmpeg-devel] Re: av_seek_frame() on a h264 encoded MP4 file

bond b-o-n-d
Tue Dec 6 12:25:30 CET 2005


> Date: Mon, 5 Dec 2005 14:01:20 +0100
> From: Jack Jansen <Jack.Jansen at cwi.nl>
> Subject: [Ffmpeg-devel] av_seek_frame() on a h264 encoded MP4 file
> To: ffmpeg-devel at mplayerhq.hu
> Message-ID: <83CFFA1E-2D5C-4DC7-B141-6E3C914E592E at cwi.nl>
> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
>
> I try to do an av_seek_frame() on an mp4 movie with a H264 track
> inside it. This fails, because somehow the file contains an edit list
> (I'm not sure I understand this bit, because I didn't create any edit
> lists in the file). But, what is worse is that the call to
> av_seek_frame() leaves the stream in a funny state: the frames I read
> have weird blocky color effects, which doesn't go away until about 10
> seconds later (the next I frame, maybe?).
>
> I tried debugging this but I got lost: initially I thought
> av_read_frame_flush() was to blame (which could be the case if it
> flushed the initial I frame), but my workaround of calling
> av_seek_frame(m_con, -1, 0, AVSEEK_FLAG_BYTE) after the first
> av_seek_frame call failed didn't work.
>
> So now I turn to you: any idea what could be going on here? I can
> provide the mp4 file if needed.

i cant really help you, but i doubt the ffmpeg mp4 demuxer cares about edit
lists at all (edit lists can be used for setting an audio/video delay for
example)





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