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When I watch this youtube video - http://www.youtube.com/watch?v=KqnB2Ew0SFM&feature=BFa&list=WL2AA75EB885F2A4B4 it's in flash.

But when I click on http://www.youtube.com/watch?v=LD3ywXEydyk - that video is in html5.

Why are some videos in flash and some in html5? Also how can I force html5 for videos (for example, when I want to use the speed-up feature)?

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More strange example, and updating to 2014: a VEVO's video need Flash, many other (like this other copyrighted video) not need; using Firefox 29 with Ubuntu. – Peter Krauss Oct 28 '14 at 0:36
up vote 3 down vote accepted

The issue with the first example is that you are not going straight to the video. Instead of watching as part of a playlist, view the video only: http://youtu.be/KqnB2Ew0SFM

This is the full URL: http://www.youtube.com/watch?v=KqnB2Ew0SFM Now you'll get all the features supported by HTML5.

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You can do this by changing the url with ANY video.

Simply take the video id (like the KqnB2Ew0SFM above in the 1st answer

and add it after this: http://www.youtube.com/watch_popup?v=

(getting http://www.youtube.com/watch_popup?v=KqnB2Ew0SFM if using that video)

This way, the video takes up your whole screen and is forced to play in HTML5 (well, just make sure you're in the HTML5 player trial to begin with, if you aren't already...you can opt-in by going to www.youtube.com/html5)


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The previous answers don't work for me, however switching my user agent to iPad/Safari will enable HTML5 playback.

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This should be a comment. – serenesat Sep 25 '15 at 3:03
@serenesat no it shouldn't. It answers the question. Answers don't belong in comments. – Abhi Beckert Sep 25 '15 at 19:56

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