- Edited
The Dev Tracker takes a different account? Well anyway, on the matter of Firefox VAAPI:
GPU: R9 270X
DE: Budgie
System: up to date - stable
After changes, About:support shows Compositing:Webrender, however all three line under WEBRENDER_COMPOSITOR are blocklisted.
There is no VAAPI section.
After starting Firefox, this shows in the console:
ATTENTION: default value of option mesa_glthread overridden by environment.
libva info: VA-API version 1.18.0
libva info: User environment variable requested driver 'radeonsi'
libva info: Trying to open /usr/lib64/dri/radeonsi_drv_video.so
libva info: Found init function __vaDriverInit_1_18
ATTENTION: default value of option mesa_glthread overridden by environment.
libva info: va_openDriver() returns 0!<
When going to the page of the Costa Rica video, which was served in VP9/opus, this seemed interesting:
Utility 5450: MediaSupervisor #1]: D/PlatformDecoderModule Agnostic decoder supports requested type 'audio/opus'
[RDD 5448: MediaPDecoder #1]: D/PlatformDecoderModule FFVPX: Initialising VA-API FFmpeg decoder
[RDD 5448: MediaPDecoder #1]: D/PlatformDecoderModule FFVPX: Format vp9 is not accelerated
[RDD 5448: MediaPDecoder #1]: D/PlatformDecoderModule FFVPX: Initialising FFmpeg decoder
[RDD 5448: MediaPDecoder #1]: D/PlatformDecoderModule FFVPX: codec vp9 : Google VP9
[Child 5353: MediaPDecoder #3]: D/PlatformDecoderModule Sandbox RDD decoder supports requested type video/vp9
[Child 5353: RemVidChild]: D/PlatformDecoderModule RemoteMediaDataDecoder[7f4729e8c350] ::RemoteMediaDataDecoder: 7f4729e8c350 is created
[RDD 5448: MediaSupervisor #1]: D/PlatformDecoderModule FFmpeg decoder supports requested type 'video/vp9'!<
According to wikipedia VP9 decode wasn't added by AMD until Raven Ridge APU/RDNA discreet, so sure enough it was software decoding. But it looks from the above that at least part of the process worked.
Mod edit: Fixed link