Firefox 37 on Ubuntu 14.10 can't use Media Source Extensions on YouTube

cor-el said

MSE is still disabled by default in Firefox 37 on Linux.

• media.mediasource.enabled = false

• http://mxr.mozilla.org/mozilla-central/source/modules/libpref/init/all.js#445

445 // Whether to enable MediaSource support.
446 // We want to enable on non-release  builds and on release windows and mac
447 // but on release builds restrict to YouTube. We don't enable for other
448 // configurations because code for those platforms isn't ready yet.

Ah, there really should have been something in the release notes about that.

cor-el said

MSE is still disabled by default in Firefox 37 on Linux.

• media.mediasource.enabled = false

• http://mxr.mozilla.org/mozilla-central/source/modules/libpref/init/all.js#445

445 // Whether to enable MediaSource support.
446 // We want to enable on non-release  builds and on release windows and mac
447 // but on release builds restrict to YouTube. We don't enable for other
448 // configurations because code for those platforms isn't ready yet.

I saw that when I got the same showing on the Youtube html5 page. If you set the relevant mse flags to "true", video playback breaks (at least for some videos). Why is that?

That is the reason why it is still false on Linux. If the devs are confident that it will work then this pref will be true by default.

1083588 – (youtube-mse) [META] Tracking bug for YouTube MSE issues:

• https://bugzilla.mozilla.org/show_bug.cgi?id=1083588