I'm running Firefox on Arch Linux with KDE Plasma, and videos occasionally freeze visually while the audio continues for a few seconds. It happens most often when the video is playing in another tab and I switch back to it, but I've also seen it across several different websites, so it doesn't seem limited to one service. I've tried enabling and disabling hardware acceleration, with no noticeable difference, and I haven't observed any unusual CPU or memory spikes. The problem doesn't occur in Chromium or in standalone video players. What could be causing this specifically in Firefox?
3 Answers
Older Intel graphics can have compatibility problems with newer Mesa drivers, and the mesa-amber package may help with legacy hardware. That explanation seems unlikely here, though, if the system is using a modern GPU or processor.
The Firefox package source can sometimes affect graphics and codec behavior on Linux. It may be worth comparing the Arch-packaged version with Mozilla’s official build to see whether the issue is specific to the distribution package.
I’m currently using the version from Arch’s official repositories.
Check Firefox’s graphics diagnostics by opening about:support and looking at the hardware video decoding entries. If a codec shows as blocked or unavailable, Firefox may be falling back to software decoding or having trouble switching between decoding modes.
The only notable entry was VP8_HW_DECODE in the environment section, showing BLOCKLIST_FEATURE_FAILURE_VIDEO_DECODING_MISSING.
The system has an AMD Ryzen 9 7900, so outdated hardware is probably not the cause.