====== VP9 ======

  * [[https://github.com/webmproject/libvpx/tags|GitHub downloads]]
  * [[https://sites.google.com/a/webmproject.org/wiki/ffmpeg/vp9-encoding-guide|webm wiki: VP9 Encoding Guide]]
  * [[https://trac.ffmpeg.org/wiki/Encode/VP9|FFmpeg and VP9 Encoding Guide]]
  * [[http://ffmpeg.org/ffmpeg-all.html#libvpx|ffmpeg libvpx documentation]]
  * [[https://developers.google.com/media/vp9/bitrate-modes|VP9 Bitrate Modes in Detail]] - Google's
  * [[http://wiki.webmproject.org/vp9/vp9-tips|VP9 Tips - Encoding Modes and Recommended Command Line Options]] - upstream's wiki
  * [[https://slhck.info/video/2017/02/24/crf-guide.html|CRF Guide (Constant Rate Factor in x264, x265 and libvpx)]]
  * [[https://github.com/HandBrake/HandBrake-docs/tree/master/source/docs/en/latest/technical|HandBrake github repo of documentation]]

==== vpxenc ====

By default, ''vpxenc'' will use 2-pass method for encoding.

To gain a CRF-type result, use ''--end-usage=cq --cq-level=<arg>'' format, and then a 1-pass encode ''--passes=1'' Using this, ''vpxenc'' uses a default CQ of 32.

I get different encoding times on multiple runs, even though it's producing the exact same files, so watch out for that.


==== HandBrake ====

By default, HandBrake uses a CQ of 22.

HandBrake will only use 2-passes if a bitrate is set as well.

==== ffmpeg ====

You can use ''ffmpeg'' to get a deep level of output to see what it's doing, it uses the default CRF of 32:

<code>
ffmpeg -loglevel debug -i sample.y4m -vcodec libvpx-vp9 sample.webm
</code>

Relevant output:

<code>
[libvpx-vp9 @ 0x55a6e613e3c0]   VP8E_SET_CPUUSED:             1
[libvpx-vp9 @ 0x55a6e613e3c0]   VP8E_SET_ARNR_MAXFRAMES:      0
[libvpx-vp9 @ 0x55a6e613e3c0]   VP8E_SET_ARNR_STRENGTH:       3
[libvpx-vp9 @ 0x55a6e613e3c0]   VP8E_SET_ARNR_TYPE:           3
[libvpx-vp9 @ 0x55a6e613e3c0]   VP8E_SET_STATIC_THRESHOLD:    0
[libvpx-vp9 @ 0x55a6e613e3c0]   VP8E_SET_CQ_LEVEL:            32
[libvpx-vp9 @ 0x55a6e613e3c0]   VP9E_SET_COLOR_SPACE:         0
[libvpx-vp9 @ 0x55a6e613e3c0]   VP9E_SET_COLOR_RANGE:         0
[libvpx-vp9 @ 0x55a6e613e3c0]   VP9E_SET_TARGET_LEVEL:        255
</code>