When testing patches for #77460 and #77461, I noticed that neither
mullvad nor torbrowser can play live videos. ex. if you launch
either browser, navigate to youtube.com, search "live" and click
on any video with the red "live" badge, you get a "Your browser
can’t play this video" error.
If I launch Mullvad from a shell, I see this output:
[Child 22618, MediaDecoderStateMachine #1] WARNING:
Decoder=7efdca045b00 Decode error: NS_ERROR_DOM_MEDIA_FATAL_ERR
(0x806e0005) - Error no decoder found for audio/mp4a-latm: file
/tmp/guix-build-mullvadbrowser-14.0.7.drv-0/firefox-mullvad-browser-128.8.0esr-14.0-1-build2/dom/media/MediaDecoderStateMachineBase.cpp:167
This seems related to #72265, which was a report about LibreWolf
not enabling hardware acceleration for video decoding; after
applying the provided patch, the same problem resulted. I think
the same situation is happening with these browsers. I don’t have
a satisfying fix; LW still has no hwaccel support, and neither
does Firefox in nonguix.
Mullvad’s about:support claims AAC is supported with hardware
acceleration. LATM is a container format[1], not a codec, and
doesn’t show up anywhere on that page. Per the FFmpeg changelog,
LATM support was added to in version 0.9(!), and doesn’t appear to
have a configure flag to control whether it’s enabled or not. So
it’s not clear to me why Firefoxen aren’t able to decode these
streams.
Thanks,
-- Ian
[1]:
https://en.wikipedia.org/wiki/Advanced_Audio_Coding#Container_formats
