[FFmpeg-devel] Possible concealment bug

Michael Niedermayer michaelni at gmx.at
Sat Oct 8 03:16:37 CEST 2011

On Fri, Oct 07, 2011 at 03:33:39PM -0700, Hardik Sharma wrote:
> After some analysis on my results, I am thinking that the error I am getting is a possible bug. 
> My problem and the analysis is as follows-
> I encoded the yuv foreman sequence with 300 slice size, bitrate 512kbps, framerate 30 and GOP size 20 frames (aka keyint 20). I am getting 2488 number of slices for this 300 frame video sequence.      
> I tried to check some values by dropping each and every slice one by one. Some couple of 200 slices are such that out of 2488 slices that if I drop any of those slice, the error goes beyond the gop all over the remaining frame. It is defeating the purpose of keeping gop size and putting key frame in the start of every gop. Also as the error spread from that slice to all the remaining frames, it also drops frame during decoding. I got a drop of around 25-27 frames and thats a lot to drop your PSNR drastically. Please let me know regarding this problem.

Please provide a reproduceable testcase.

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Let us carefully observe those good qualities wherein our enemies excel us
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