[Libav-user] decoding video frames

Alex Cohn alexcohn at netvision.net.il
Thu May 10 16:03:04 CEST 2012

On Thu, May 10, 2012 at 3:43 PM, Bob Self <bobslf at gmail.com> wrote:
> I'm trying to decode video frames. The decoding loop prints this message:
>      [mpeg4 @ 00823420] Invalid and inefficient vfw-avi packed B
> frames detected
> After that it prints these lines over and over:
>      [mpeg4 @ ...] slice end not reached but screenspace end (5 left
> 78000, score= -2)
>      [mpeg4 @ ...] concealing 1350 DC, 1350 AC, 1350 MV errors
> What causes these warning messages? Is this the correct way to decode video?
> thanks,
> Bob

Such problems could be caused by some strange video steams. Therefore
it's important to decode your file with the latest command-line
ffmpeg. If its output is not as expected, it's also recommended to use
alternative players: either the video may be corrupt, or there may be
a bug in ffmpeg.

But if ffmpeg succeeds, your code must be analyzed for problems.

Alex Cohn

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