Even though i have pulseaudio installed and running, often when i try to play an audio file i get a warning "to play audio, you may need to install pulseaudio". When i reset the 'media.decoder-doctor.MediaCannotInitializePulseAudio.formats' (from string "*") entry in about:config and restart firefox the audio file plays without problems. I also noticed that the 'media.decoder-doctor.MediaCannotInitializePulseAudio.formats' entry has disappeared in about:config after the restart. I don't want to have to go into the about:config and restart firefox every time i want to play an audio file! Please fix firefox, no other applications fail to play audio on my system.

Thanks, Martijn. I suspect this belongs in Core :: Audio/Video Playback, so moving there for triage.

Matthew can you try to help debugging this for me?

Hi Martin, thanks for the report. What Firefox version and Linux distribution are you running? Do you know if PulseAudio running as part of your display session or started on-demand when applications attempt to play sound (is there a PA server process during the period where audio is failing in Firefox?)? I suspect if you ignore the decoder-doctor prefs and simply restart Firefox, that would also cause audio to start working again temporarily. Also, if you play audio with another application, it should cause audio to start working in Firefox again. My guess is that your PulseAudio is configured to run on-demand (and quit when idle); starting Firefox causes PA to start up, but it eventually quits on idle and then audio fails. Due to changes in sandboxing and audio remoting in Firefox 58 and 59, Firefox lost the ability to trigger PA to start on-demand (except when Firefox first starts). That was fixed in bug 1434392 and bug 1443612, which are present in Firefox 60 along with bug 1434156 which enabled audio remoting.

Firefox: 59.0.2 Distribution: Fedora 27 In the mean time I've configured PulseAudio to start as part of my display session, so far that seems to do the trick. Once Firefox is updated to version 60 I'll check if PA is started on demand again.

Can you please clearthe needinfo request flag?

Done. Thanks for responding. It sounds like this bug is the same as bug 1434392 and bug 1443612, so I'll mark this as a dupe of one of them.