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vp8 [2020/06/09 04:12] beandog |
vp8 [2023/04/19 22:17] (current) beandog [Notes] |
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| * [[https://trac.ffmpeg.org/wiki/Encode/VP8|ffmpeg wiki: Encode VP8]] | * [[https://trac.ffmpeg.org/wiki/Encode/VP8|ffmpeg wiki: Encode VP8]] | ||
| * [[http://ffmpeg.org/ffmpeg-all.html#libvpx|ffmpeg libvpx documentation]] | * [[http://ffmpeg.org/ffmpeg-all.html#libvpx|ffmpeg libvpx documentation]] | ||
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| + | ==== Notes ==== | ||
| + | |||
| + | Both VP8 and [[VP9]] are a bit confusing on how to get good encodes related to specific levels of quality, when using the documentation and ''vpxenc'' help output as references. | ||
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| + | In it's simplest approach, if using ''vpxenc'', use ''max-q'' as the target CRF -- the encoder won't drop quality below that level (starts at 0, ends at 63). | ||
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| + | For ''ffmpeg'', use ''-crf'' with your number and ''-b:v 0'' is required. | ||
| + | |||
| + | For HandBrake, use ''-q'' with your CRF. I can't tell from docs or the code if it's passing anything about min-q and max-q to the encoder, but I don't think it is. <del>I think it's using libavcodec to do crf=X and then b:v of 0.</del> | ||
| ==== Encoding Quality ==== | ==== Encoding Quality ==== | ||
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| With the defaults, vpxenc will create low quality encodes, its bitrate is too low. It will have to be bumped up to get some good quality. | With the defaults, vpxenc will create low quality encodes, its bitrate is too low. It will have to be bumped up to get some good quality. | ||
| - | When using ffmpeg, pass ''-b 0'' (bitrate 0) so that it doesn't limit bitrate. Also use a CRF. For very high quality encodes, I'd say around 6 to 8. | + | SETTING crf and b:v 0 only works on VP9, DESPITE what the ffmpeg docs say. |
| + | <del>When using ffmpeg, pass ''-b 0'' (bitrate 0) so that it doesn't limit bitrate. Also use a CRF. For very high quality encodes, I'd say around 6 to 8. | ||
| <code> | <code> | ||
| ffmpeg -i video.y4m -vcodec libvpx -crf 6 -b:v 0 -y video.mkv | ffmpeg -i video.y4m -vcodec libvpx -crf 6 -b:v 0 -y video.mkv | ||
| - | </code> | + | </code></del> |
| - | HandBrake: | + | HandBrake's default CRF for VP8 is 22. |
| <code> | <code> | ||
| - | HandBrakeCLI -i video.y4m -e VP8 -q 6 -o video.mkv | + | HandBrakeCLI -i video.y4m -e VP8 -q 18 -o video.mkv |
| </code> | </code> | ||
