Excessive CPU usage during playback of VP8/9 videos since commit c64c03478fac7f6b8733e2703035a71ecf0244ff about renpy-build

[renpytom]

That's convicing. I've re-enabled MMX for now.

[gojira667]

Of course I forgot that the test VP9 video is YUV444... You still get a nice reduction in CPU usage with VP9 and YUV420 movies.

[gojira667]

I made a sample 4k project using Tears of Steel as that's what Google uses in their examples. Downloaded it and took a short clip near the start:

ffmpeg -ss 00:00:09 -to 00:00:25 -i tearsofsteel_4k.mov -c copy tearsofsteel_4k_09s-25s.mov

Butchered it to 60 FPS, YUV420 and transcoded to VP8, VP9 then later AV1 both at 4k & 1080p (encodes are not equivalent to each other & may contain unused options):

ffmpeg transcodes:

ffmpeg -i tearsofsteel_4k_09s-25s.mov -vf scale=3840x2160 -tile-columns 3 -g 240 -c:v libvpx -r 60 -row-mt 1 -crf 12 -b:v 23552K -pass 1 -pix_fmt yuv420p -an -f null /dev/null && ffmpeg -i tearsofsteel_4k_09s-25s.mov -vf scale=3840x2160 -tile-columns 3 -c:v libvpx -row-mt 1 -crf 12 -b:v 23552K -pass 2 -pix_fmt yuv420p -g 240 -r 60 -c:a libopus tearsofsteel_4k_09s-25s-60.webm

ffmpeg -i tearsofsteel_4k_09s-25s.mov -vf scale=3840x2160 -tile-columns 3 -g 240 -c:v libvpx-vp9 -r 60 -row-mt 1 -crf 12 -b:v 23552K -pass 1 -pix_fmt yuv420p -an -f null /dev/null && ffmpeg -i tearsofsteel_4k_09s-25s.mov -vf scale=3840x2160 -tile-columns 3 -c:v libvpx-vp9 -r 60 -row-mt 1 -crf 12 -b:v 23552K -pass 2 -pix_fmt yuv420p -g 240 -c:a libopus tearsofsteel_4k_09s-25s-vp9-60.webm

ffmpeg -i tearsofsteel_4k_09s-25s.mov -vf scale=3840x2160 -g 300 -c:v libaom-av1 -r 60 -row-mt 1 -tiles 4x1 -crf 16 -b:v 23552K -pass 1 -pix_fmt yuv420p -an -f null /dev/null && time ffmpeg -i tearsofsteel_4k_09s-25s.mov -vf scale=3840x2160 -c:v libaom-av1 -row-mt 1 -tiles 4x1 -crf 16 -b:v 23552K -pass 2 -pix_fmt yuv420p -g 300 -r 60 -c:a libopus tearsofsteel_4k_09s-25s-av1-60.webm

ffmpeg -i tearsofsteel_4k_09s-25s.mov -vf scale=1920x1080 -tile-columns 3 -g 240 -c:v libvpx -r 60 -row-mt 1 -crf 12 -b:v 23552K -pass 1 -pix_fmt yuv420p -an -f null /dev/null && ffmpeg -i tearsofsteel_4k_09s-25s.mov -vf scale=1920x1080 -tile-columns 3 -c:v libvpx -row-mt 1 -crf 12 -b:v 23552K -pass 2 -pix_fmt yuv420p -g 240 -r 60 -c:a libopus tearsofsteel_1080_09s-25s-60.webm

ffmpeg -i tearsofsteel_4k_09s-25s.mov -vf scale=1920x1080 -tile-columns 3 -g 240 -c:v libvpx-vp9 -r 60 -row-mt 1 -crf 12 -b:v 23552K -pass 1 -pix_fmt yuv420p -an -f null /dev/null && ffmpeg -i tearsofsteel_4k_09s-25s.mov -vf scale=1920x1080 -tile-columns 3 -c:v libvpx-vp9 -r 60 -row-mt 1 -crf 12 -b:v 23552K -pass 2 -pix_fmt yuv420p -g 240 -c:a libopus tearsofsteel_1080_09s-25s-vp9-60.webm

ffmpeg -i tearsofsteel_4k_09s-25s.mov -vf scale=1920x1080 -g 300 -c:v libsvtav1 -preset 1 -r 60 -row-mt 1 -tiles 4x1 -crf 16 -b:v 23552K -pass 1 -pix_fmt yuv420p -an -f null /dev/null && time ffmpeg -i tearsofsteel_4k_09s-25s.mov -vf scale=1920x1080 -c:v libsvtav1 -preset 1 -row-mt 1 -tiles 4x1 -crf 16 -b:v 23552K -pass 2 -pix_fmt yuv420p -g 300 -r 60 -c:a libopus tearsofsteel_1080_09s-25s-av1-stv-60.webm

Well -vf scale= didn't do quite what I was expecting. Played via renpy.movie_cutscene looping once each time; playback order 4k:VP8-VP9-AV1, 1080:VP8-VP9-AV1:

renpy.movie_cutscene()

    $ renpy.movie_cutscene("images/tearsofsteel_4k_09s-25s-60.webm", loops=1)
    $ renpy.movie_cutscene("images/tearsofsteel_4k_09s-25s-vp9-60.webm", loops=1)
    $ renpy.movie_cutscene("images/tearsofsteel_4k_09s-25s-av1-60.webm", loops=1)
    $ renpy.movie_cutscene("images/tearsofsteel_1080_09s-25s-60.webm", loops=1)
    $ renpy.movie_cutscene("images/tearsofsteel_1080_09s-25s-vp9-60.webm", loops=1)
    $ renpy.movie_cutscene("images/tearsofsteel_1080_09s-25s-av1-stv-60.webm", loops=1)

New Ryzen system (Debian sid)

Default renpy-8.1.1-sdk lib:

MMX

As you can see both the VP8 & VP9 playback see a significant reduction in CPU with a MMX enabled build. AV1 is largely unaffected with this CPU.

Then I actually read the Tears of Steel about page. I did not include the credit scroll, so I'm not entirely certain how kosher it is to share it like this.

But it's trivial to reproduce as it applies to all VP8/VP9 videos.