hi Jerry, we are getting a number of similr reports and are trying to debug this issue. could you try the following two options and report back if either of them works in addressing the issue?:

• enter about:config into the firefox address bar (confirm the info message in case it shows up) and search for the preferences named layers.mlgpu.enabled & layers.mlgpu.enable-on-windows7. double-click it and change their value to false and restart the browser once.

• after you've tried the first option, please reset the preferences to their default value again and now switch media.wmf.use-nv12-format to false and see if this helps after a restart...

many thanks!

I tried to do what was asked, but when I typed in about:config, it said if I proceeded it could cancel out my warranty, so I didn't proceed with the suggested fix.

Are you guys still trying to fix the problem, because the problem is still there.

Thank you!

hi jmoore1955, yes we're fixing the problem in https://bugzilla.mozilla.org/show_bug.cgi?id=1417442

please note that the message about the warranty is a bit of a joke - firefox as a free product doesn't have a warranty in the first place. we just don't want people go to that page and randomly change stuff :)) in the meantime we also know the exact configuration that can fix the playback issue: enter about:config into the firefox address bar (confirm the info message in case it shows up - you got our blessing to do that) & search for the preference named media.windows-media-foundation.use-nv12-format. double-click it and change its value to false and close/reopen firefox once.