> This patch is not correct. > > this code is not used if AV_CODEC_FLAG_BITEXACT is set, because it is > not bit exact ... > > Also the case where the off by 1 error occurs is a rare corner case, > Compared to the errors introduced by the IDCT this is not significant > > If you want to optimize the bit exact version, feel free to do so. > It may be faster to use xor -1 before and after avg for this though
Thank you for the review. VC-1 spec is defined bit exact, including the inverse transform. This code is used by the VC-1 decoder and as I was under the impression that the VC-1 decoder ought to be bit exact without any additional command line options, I tried to resolve the issue. As this code is guarded by AV_CODEC_FLAG_BITEXACT, i agree that the proposed solution is not appropriate. The underlying question remains though. Should the VC-1 decoder fully conform to spec or do we allow small deviations? In addition, the VC-1 fate tests put the -bitexact option after the input file (-i). I could only get the bitexeact working if it was put before the input file. Thus, I think the current vc-1 fate-tests do not use the bit exact version. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
