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vp8 [2020/05/23 07:22] – created beandogvp8 [2023/04/20 04:17] (current) – [Notes] beandog
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 ====== VP8 ====== ====== VP8 ======
  
 +  * [[https://www.webmproject.org/docs/encoder-parameters/|VP8 Encode Parameter Guide]]
   * [[https://scholarworks.rit.edu/cgi/viewcontent.cgi?article=4188&context=theses|An Analysis of VP8, a new video codec for the web]]   * [[https://scholarworks.rit.edu/cgi/viewcontent.cgi?article=4188&context=theses|An Analysis of VP8, a new video codec for the web]]
 +  * [[http://wiki.webmproject.org/ffmpeg|webm wiki: FFmpeg VP8 Encoding Options]]
 +  * [[https://trac.ffmpeg.org/wiki/Encode/VP8|ffmpeg wiki: Encode VP8]]
 +  * [[http://ffmpeg.org/ffmpeg-all.html#libvpx|ffmpeg libvpx documentation]]
 +
 +==== 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.
 +
 +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).
 +
 +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 ====
 +
 +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.
 +
 +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>
 +ffmpeg -i video.y4m -vcodec libvpx -crf 6 -b:v 0 -y video.mkv
 +</code></del>
 +
 +HandBrake's default CRF for VP8 is 22.
 +
 +<code>
 +HandBrakeCLI -i video.y4m -e VP8 -q 18 -o video.mkv
 +</code>

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