I’m going to use this guide to downgrade Firefox to something around version 127 or below because I did not have this issue with earlier versions of FF.
Btw where does Firefox store crash logs? I typed “about:crashes” in the URL bar but it says that “No crash reports have been submitted”. I have also used journalctl to find these errors but I’m not sure how relevant they are:
org.mozilla.firefox.desktop[15004]: Exiting due to channel error.
org.mozilla.firefox.desktop[49355]: [Parent 2, Main Thread] WARNING: g_strv_length: assertion ‘str_array != NULL’ failed: ‘glib warning’, file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:187
firefox-bin[49355]: g_strv_length: assertion ‘str_array != NULL’ failed
@sun_is_ra Oh definitely related, it was working ok under 22.04 not 24.04, but I suspect it has something to do with decoder ffmpeg, as other applications using it also have issues with H.264 v10 video. However Thorium does not. Perhaps it has it’s own decoder rather than using ffmpeg.