On Thu, Aug 29, 2019 at 10:14 AM Jan Ekström <jee...@gmail.com> wrote: > > On Thu, Aug 29, 2019 at 7:17 PM Carl Eugen Hoyos <ceffm...@gmail.com> wrote: > > > > Am Do., 29. Aug. 2019 um 18:12 Uhr schrieb Elliott Karpilovsky > > <elliottk-at-google....@ffmpeg.org>: > > > > > > On Wed, Aug 28, 2019 at 3:11 PM Carl Eugen Hoyos <ceffm...@gmail.com> > > > wrote: > > > > > > > > Am Mi., 28. Aug. 2019 um 23:26 Uhr schrieb Elliott Karpilovsky > > > > <elliottk-at-google....@ffmpeg.org>: > > > > > > > > > > Current default is 200kbps, which produces inconsistent > > > > > results (too high for low-res, too low for hi-res). Use > > > > > CRF instead, which will adapt. Affects vp8/vp9. Also > > > > > have VP8 use a default bitrate of 256kbps. > > > > > > > > Would it simplify the patch if -crf 0 would indicate lossless encoding? > > > > > I do not believe so. I believe that there would be more code changes > > > to switch the checks from ctx->lossless to ctx->crf, > > > > Of course but that wasn't my question. > > I believe it is a horrible bug that x264 uses crf 0 for lossless encoding, > > while libvpx uses another option. If fixing this bug simplifies your > > patch, I believe it is worth the effort. > > > > Just for the record, libx264 only does lossless for CRF=0 for 8bit > coding. The quantizer range for CRF was expanded downwards for higher > bit depths since the results were similar for lossy coding. In that > case you either have to poke the right negative value, or set > quantizer to zero - which is the option that works for all bit depths > with libx264. > > That said, I do not have heavy objections one way or another regarding > how the libvpx wrapper defines CRF (as I think the definition for VP8 > and VP9 is already in general different from what libx264 does - like > bit rate being required for VP8 etc). Just wanted to refresh people's > minds regarding libx264's CRF behavior with lossless coding. > > Best regards, > Jan
Thanks for the context. My preference is to keep this patch about changing the default behavior. I would not oppose someone else writing another patch to change CRF=0 to lossless, but it feels like these two should be separate. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
