HTML5 media support may lead to fingerprinting
I have found out that Tor Browser 4.0 can play videos that older versions of TBB couldn't. It's because the new firefox can load gstreamer plugins into the browser and play mp4 files (inside what I believe to be HTML5 player). I fear this means that gstreamer is able to connect directly or send sensitive information to the server where the video file is hosted. If you change "media.gstreamer,enabled" to "false", it prevents gstreamer from being loaded, but it might cause fingerprinting problems.
Any thoughts on this? Should this be enabled? Or maybe change it in later versions.
It could still be used maybe in TAILS, to make vimeo and other websites able to play videos (using gstreamer in a more secure environment).