Enable Hardware Acceleration in Firefox & Get 1080p in Youtube's HTML5 player
Youtube's HTML5 player in Firefox limits the maximum video resolution to 720p. Other video resolutions including 144p, 240p and 480p are also not provided. To enable all available video resolutions in Firefox open a new tab and go to: Then search for; Double click on "media.mediasource.enabled" and "media.mediasource.webm.enabled" in order to change their value to "true".
Enable Hardware Acceleration in Firefox & Get 1080p in Youtube’s HTML5 player