> In an ideal world, crf 0 would force all other settings for a lossless encoding.
I forgot to say that if "-lossless 1" is set, "crf" will also be 0 (in libaom, internally). All those conditions will be forced (ot at least checked by libaom) if we execute this line: > codecctl_int(avctx, AV1E_SET_LOSSLESS, ctx->lossless); So, how about executing this line if the "-crf 0" is set? libaom changes so fast, so this might be a more robust way to ensure lossless encoding, rather than setting those settings by hand. If it's okay, I will make an additional patch. 2020年4月5日(日) 0:34 Carl Eugen Hoyos <ceffm...@gmail.com>: > Am Sa., 4. Apr. 2020 um 13:17 Uhr schrieb Ryo Hirafuji > <ryo.hiraf...@link-u.co.jp>: > > > > > So "crf 0" already has a meaning different from all other crf values? > > > > No. "crf 0" has the same meanings. It just makes the quality better than > > "crf 1". > > That was my question, sorry for being unclear. > > > I read libaom again, and I apologize for my wrong explanation: > > I found that if certain conditions are met, "crf 0" also generates > > lossless videos. > > > > If these conditions are not met, "-crf 0" will be lossless: > > > > <<FFmpeg options>> > > "-bit_rate 0" (which means, enccfg.rc_end_usage = AOM_Q) > > "-aq-mode none" > > "-enable_restoration 0" > > > > <<the libaom settings which can't be configured from FFmpeg yet>> > > AV1E_SET_ENABLE_CHROMA_DELTAQ must be 0 > > AV1E_SET_ENABLE_SUPERRES must be 0 > > > > Thus, at least, "-lossless" does have a different meaning from "-crf 0", > > so I think it would be useful to add "-lossless" flags. > > In an ideal world, crf 0 would force all other settings for a lossless > encoding. > > Carl Eugen > _______________________________________________ > 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". _______________________________________________ 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".
