I will use this bug to address the review suggestions and add tests for bug 1878510 and bug 1900191.

I still see issues with buffering on youtube when H.264 (avc1/mp4a) is used. It can be tested with h264ify installed.

(In reply to gudvinr from comment #1)

I still see issues with buffering on youtube when H.264 (avc1/mp4a) is used. It can be tested with h264ify installed.

What version of Firefox you're using? If that happens on h264, that will be a different problem than we addressed before. If you use Firefox Nightly, could you capture a profiled result by following this instruction? If you're using other version, follow the same instruction, but after selecting the media playback preset, paste following log modules timestamp,HTMLMediaElement:4,HTMLMediaElementEvents:4,cubeb:5,PlatformDecoderModule:5,AudioSink:5,AudioSinkWrapper:5,MediaDecoderStateMachine:4,MediaDecoder:4,MediaFormatReader:5,GMP:5,EME:5,MediaSource:5,MediaSourceSamples:5 in New log modules: before starting profiling.

Thank you!

(In reply to Alastor Wu [:alwu] from comment #2)

If you use Firefox Nightly, could you capture a profiled result by following this instruction? If you're using other version, follow the same instruction, but after selecting the media playback preset, paste following log modules timestamp,HTMLMediaElement:4,HTMLMediaElementEvents:4,cubeb:5,PlatformDecoderModule:5,AudioSink:5,AudioSinkWrapper:5,MediaDecoderStateMachine:4,MediaDecoder:4,MediaFormatReader:5,GMP:5,EME:5,MediaSource:5,MediaSourceSamples:5 in New log modules: before starting profiling.

Unfortunately, profile just getting stuck on uploading after I stop logging. Not sure what to do here, there are no error messages, no progress indication. Just placeholder.

What version of Firefox you're using?

Latest stable 128.0

Operating System: Arch Linux
Kernel Version: 6.9.10-arch1-1 (64-bit)
Graphics Platform: X11
Graphics Processor: AMD Radeon RX Vega M GL Graphics