On 28 April 2018 at 10:42, Hendrik Leppkes <h.lepp...@gmail.com> wrote:
> On Sat, Apr 28, 2018 at 10:44 AM, Jerome Borsboom > <jerome.borsb...@carpalis.nl> wrote: > >> 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? > > If the spec is bitexact, then our decoder should be by default as > well. Perhaps such things should be flipped around and use bitexact by > default unless the "fast" flag is specified. > > - Hendrik > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > I'd say just remove it, it'll bitrot otherwise since no one will use it. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
