You need a Firefox version that has enabled MSE (Media Source Extensions) to make YouTube offer 60 FPS. This works by default in the current 36 beta release that has a specific pref for YouTube (media.mediasource.youtubeonly) to allow this and you can see 1080p60 and 720p60 being available.

• https://www.mozilla.org/en-US/firefox/beta/
• https://www.mozilla.org/en-US/firefox/beta/all/

You can enable MSE in the current release, but this may not always work properly. MSE is still disabled in the current beta, so the YouTube HTML5 settings page still shows that MSE is disabled.

• http://www.youtube.com/html5/

I don't know how "My Subscriptions" and "Watch Later" work. You can try to clear the YouTube cookies and also check whether Flash or an HTML5 media player is used to see if that has effect.

Clear the cache and remove cookies only from websites that cause problems.

"Clear the Cache":

• Firefox/Tools > Options > Advanced > Network > Cached Web Content: "Clear Now"

"Remove Cookies" from sites causing problems:

• Firefox/Tools > Options > Privacy > "Use custom settings for history" > Cookies: "Show Cookies"

.

I tried clearing the cache and cookies but the issue still remains.

On the FPS note: I don't really want to use beta. I'm guessing it will eventually arrive to the stable release. Hopefully sooner than later.

You may have a corrupt cookies.sqlite file.

Type about:support in the address bar and press enter.

Under the page logo on the left side you will see Application Basics. Under this find Profile Folder. To it’s right press the button Show Folder. This will open your file browser to the current Firefox profile. Now Close Firefox.

Locate the cookies.sqlite file. Then rename or delete it. Restart Firefox.

Separate Issue; Your System Details shows;

Installed Plug-ins

Battlelog Game Launcher (2.6.2) Battlelog Game Launcher (2.5.1)

Having more than one version of a program may cause issues.

Deleting cookies.sqlite didn't help.

I doubt that deleting Battlelog Game Launcher will help.

Bump! Anybody?

FredMcD said

Separate Issue; Your System Details shows; Installed Plug-ins Battlelog Game Launcher (2.6.2) Battlelog Game Launcher (2.5.1) Having more than one version of a program may cause issues.

Removing Battlelog Game Launcher didn't help. Still have the problem.

While Battlelog Game may not be causing this issue, it can still led to other problems. Just ask any programer.

Security issue: Update your Flash Player v16.0.0.296
https://www.adobe.com/products/flashplayer/distribution3.html

Type about:addons<enter> in the address bar to open the Add-ons Manager. Hot key; <Control>(Mac:<Command>) <Shift> A)

On the left side of the page, select Plugins. Make sure the ones you want to use are set to Ask or Allow. Including Java (not JavaScript).

Go to the web page. Once the page is loading, mouse to the address bar and Left click the icon. A window for displaying site information should come up. Select More Information. Now select Permissions. In the menu, Make sure the ones you want to use are set to Ask or Allow. Including Java (not JavaScript).

Don't know what issues Battlelog Game Launcher has but how else am I supposed to play Battlefield... I updated the Flash Player. All my plugins are set to Ask, a couple Always. Only Java Deployment Toolkit is set to Never (Disabled) since it says "Known to be vulnerable. Use with Caution." All permissions are set to Use Default. Switching everything to Ask, and Allow didn't change anything.

rade155 said

Don't know what issues Battlelog Game Launcher has but how else am I supposed to play Battlefield...

Remove both programs, then reinstall the current version.

Start Firefox in Safe Mode {web link} While you are in safe mode;

Type about:preferences#advanced<Enter> in the address bar.

Under Advanced, Select General. Look for and turn off Use Hardware Acceleration.

Poke around safe web sites. Are there any problems?

Start your Computer in safe mode with networking. Then start Firefox. Try Safe web sites.

Starting The Computer In Safe Mode;
Free Online Encyclopedia

That is what I did with Battlelog. Ok so starting Firefox in Safe Mod solved the issue. I did not need to turn off Use Hardware Acceleration for it to work. I could hide videos in YouTube without it turned off. So we are getting somewhere.

If it works in Safe Mode and in normal mode with all extensions (Firefox/Tools > Add-ons > Extensions) disabled then try to find which extension is causing it by enabling one extension at a time until the problem reappears.

Close and restart Firefox after each change via "Firefox > Exit" (Windows: Firefox/File > Exit; Mac: Firefox > Quit Firefox; Linux: Firefox/File > Quit)

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

So I did just that and it looks like it is Adblock Plus. After disabling it, YouTube functions work again. But this is very unfortunate as I cannot use Firefox without Adblock Plus. I tried reinstalling it but it does not help. Is there any way to make it work?

Try to ask advice at the Adblock Plus forum.

• https://adblockplus.org/forum/

Alright I will do that. Thanks for all the help guys.

Go to the web site. Click the arrow next to the AdBlock icon. In the menu, select Disable On WebSite

Yeah but Adblock is very much most important on YouTube.