[Ffmpeg-devel] H.264 decoding bug in either lavc/JM (x264 too?)

[Michael Niedermayer]

Hi

On Friday 22 July 2005 11:30, Tuukka Toivonen wrote:
> I encoded a video clip using x264 and decoded with both
> Mplayer (lavc) and JM 9.6. The two decoded videos differ
> slightly on some frames. I think this is bug, as
> H.264 should be bit exact, shouldn't it?

yes

[...]

>
> I used latest CVS Mplayer and latest SVN x264 (but same results were same
> with slightly older versions).
>
> x264 command line:
> --bframes 2 --8x8dct --b-pyramid --qp 26 --direct spatial
> The problem occurs only if using all three options --8x8dct, --b-pyramid,
> and --direct spatial. Most other options seem not to matter.

a different number of bframes causes this too?

looking just at the diff between the frames i would guess that the motion 
vectors differ sightly between JM and lavc&x264

[...]

-- 
Michael