Forgot to mention something. I don't have an account on YouTube so I don't know if that would make a difference or not. Most likely wouldn't but you never know.

Try this extension to switch between the Flash player and the HTML5 media player on the YouTube website. YouTube Flash Video Player:

• https://addons.mozilla.org/firefox/addon/youtube-flash-video-player/

Do all settings have a blue check mark except the last one (MSE & WebM VP9)?

• https://www.youtube.com/html5

cor-el said

Try this extension to switch between the Flash player and the HTML5 media player on the YouTube website. YouTube Flash Video Player:

• https://addons.mozilla.org/firefox/addon/youtube-flash-video-player/

Do all settings have a blue check mark except the last one (MSE & WebM VP9)?

• https://www.youtube.com/html5

H.264 and MSE & H.264 don't have a blue check mark either. But the other options are and it said "The HTML5 player is currently used when possible." also as a blue check mark. But all try the extension you linked me and see if that works. Hopefully it does. Thank you.

cor-el said

Try this extension to switch between the Flash player and the HTML5 media player on the YouTube website. YouTube Flash Video Player:

• https://addons.mozilla.org/firefox/addon/youtube-flash-video-player/

Do all settings have a blue check mark except the last one (MSE & WebM VP9)?

• https://www.youtube.com/html5

I tried the new extension and I'm able to watch videos in HD again c: All other settings are available now too. At first I had a little trouble concerning YouTube's search bar and my browser bar popping hoping but that seems to be fixed now. I'll keep an eye on things but so far so good. Thank you again for the help c:

If you do not have support for H.264 on your OS then the HTML5 media player will likely fail in as lot of cases and you would need the flash based player.

• https://support.mozilla.org/kb/viewing-html5-audio-and-video

Platform Update Supplement for Windows Vista and for Windows Server 2008:

• https://support.microsoft.com/en-us/kb/2117917

Hi jokergirl129:

I was having the same issue with the inability to play HD video on/in youtube.com but I found a solution without an add-on.

I initially I found an article that that stated that you need to change Media.mediasource.enabled from I assume “False” to “True”. The problem is that it’s already true and yet the Youtube.com videos were only able to play in 360 quality with no other options.

So…I tried doing the following and it worked for me. 

1.Go to the address bar (at the top of the page) and type “about:config” 2.Notice the warning about “This might void your warranty” 3.Click on the “I’ll be careful, I promise” button 4.Type in the following exact words in the “search” bar media.mediasource.

You will notice that four things come up, they are the following:

Name Status Type Value Media.mediasource.enabled Default Boolean True Media.mediasource.mp4.enabled Default Boolean True Media.mediasource.webm.enabled Default Boolean False Media.mediasource.whitelist Default Boolean True

Right click twice (2x times) on “media.mediasource.webm.enabled”. You will now notice it changes from “False” to “True”.

Name Status Type Value Media.mediasource.enabled Default Boolean True Media.mediasource.mp4.enabled Default Boolean True Media.mediasource.webm.enabled Default Boolean True Media.mediasource.whitelist Default Boolean True

Go to Youtube.com and choose any video that grabs your fancy. Go to the button underneath the video (it looks like a wagon wheel) click on it and notice you now have the option to play your videos now goes from quality 240 to 1080 HD.

Happy Trails!!!