so? any idea?

Any media related error messages in the Web Console (Firefox menu button or Tools > Web Developer)?

• https://developer.mozilla.org/Tools/Web_Console

On Windows 7, I get MP4, but I haven't been paying attention. Do you think it changed only since Firefox 43? The HTML5 support page looks happy (https://www.youtube.com/html5). ??

cor-el said

Any media related error messages in the Web Console (Firefox menu button or Tools > Web Developer)?

Nothing stood out for me (especially early when Google would have been deciding what to serve).

cor-el said

Any media related error messages in the Web Console (Firefox menu button or Tools > Web Developer)?

• https://developer.mozilla.org/Tools/Web_Console

no

jscher2000 said

On Windows 7, I get MP4, but I haven't been paying attention. Do you think it changed only since Firefox 43? The HTML5 support page looks happy (https://www.youtube.com/html5). ?? cor-el said

Any media related error messages in the Web Console (Firefox menu button or Tools > Web Developer)?

Nothing stood out for me (especially early when Google would have been deciding what to serve).

yes its happen after upgrade firefox43 all codecs looks enable on youtube/html5

I'm sure Google's scripts are testing for what video capabilities Firefox has and deciding what they think will work best. Maybe in their testing, they decided MP4 works better than VP9 in Firefox 43? Or maybe there's a glitch in their script? Unfortunately, Google's scripts tend to be very complex, so it's rare that I can follow them to a successful conclusion (usually it's just an hour of frustration).

im changin my user agent script. set to firefox 45 and its working. youtube videos playin vp9 codec anymore. solved.