1763301 - VAAPI Broken in nightly - Falls back to FFMPEG Software Decode

Status: RESOLVED WORKSFORME

(Core :: Audio/Video: Playback, defect, P3)

Description

[Irxil]

Attachment: during-video-played-log-entries.txt

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:101.0) Gecko/20100101 Firefox/101.0

Steps to reproduce:

In Firefox Nightly 101.0a1, a fix was implemented to resolve the sandbox issue for VAAPI #1758610 however Firefox continues to fallback to FFMPEG for decoding.

To replicate, using similar hardware specs as mine (Intel 11th Gen with Iris Xe graphics), go to https://www.youtube.com/watch?v=aqz-KE-bpKQ and select the 4k option. In the "Stats for nerds" section, confirm that it is playing vp9 video

While it is playing, open intel_gpu_top and monitor the usage of the Video engine

Actual results:

Upon loading the Youtube page initially, there is a small bump in the Video decode usage in intel_gpu_top however when the video is played, GPU decode remains at zero.

Expected results:

The Video decode engine should show activity during playback activities of supported formats and resolutions.

Attached are my log entries during playback (where no activity is seen in the GPU video engine)

Comment 1

[Irxil]

Attachment: before-video-played-log-entries.txt

Comment 2

[Irxil]

For further diagnosis:

OS: Fedora 35 (Wayland)

Interesting log line:

[RDD 12832: MediaSupervisor #2]: D/PlatformDecoderModule FFMPEG: VAAPI is disabled by parent decoder module.

I have set media.ffmpeg.vaapi.enabled to true so it should be enabled

Comment 3

[Tom S. (please needinfo tschuster)]

Are you running Firefox with MOZ_DISABLE_RDD_SANDBOX=1? Disabling the sandbox is probably going to be required until bug 1751363 is fixed.

Comment 4

[Irxil]

(In reply to Tom Schuster [:evilpie] from comment #3)

Are you running Firefox with MOZ_DISABLE_RDD_SANDBOX=1? Disabling the sandbox is probably going to be required until bug 1751363 is fixed.

It appears this fix just implemented in Nightly was supposed to resolve the sandbox issue so that flag shouldn't be required.

It's also hard to ascertain whether or not this is a sandbox issue as I do see an initial blip of Video decode activity when I load the Youtube page but it ceases almost immediately and remains zero as the video plays. That blip was not happening before I received the update for Nightly and I imagine the sandbox issue would have prevented any activity at all from occurring if it was still the issue.

I think this issue stems from that line in the log saying VAAPI is disabled by parent decoder module and the question is why is the parent decoder module not enabling VAAPI if the vaapi flag is set.