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 ...
Here is an extension that forces Flash on YouTube (tested on 02/05/2015).
Also, to remove the annoying fullscreen message type in the address bar: chrome://plugins/, find: "Adobe Flash Player" and check the box next to Always allowed.
I had this problem but like you lot all the fixes on the web either are payed for or ffmpegsumo.dll always comes back after a period. I have now fixed mine permanently and here is how I did it.
This is for a Windows based Computer
Find the ffmepegsumo.dll you should all know where it is located.
Right click on it and Choose properties then Choose the ...
I found a solution here: https://groups.google.com/forum/#!topic/mozilla.dev.extensions/0ZgKDAFfUDc
Here's how I disabled HTML5 video in Chrome on Windows:
Find the file called ffmpegsumo.dll where Chrome is installed (C:\Program Files (x86)\Google\Chrome\Application\30.xxxxx\ for me)
Worked for me as well, but after a while the html5 player returned. ...
You can use the YouTube Options extension for Chrome:
Update (2014-04-12): the YouTube Options extension for Chrome now costs $2:
"YouTube Options" cost $2.00 per month, below is a copy of the user agreement one has to confirm prior to using it.
This extension is based on a paid subscription model. It costs a flat
fee of $1.99 per month, with half of ...
To watch iPlayer on a Mac without Flash make it appear that the computer is an iPad.
To do this with Safari web browser turn on the "Develop" menu.
Then select "User Agent>iPad".
The only disadvantage is that the picture is iPad, or smaller, size.
The best advantage of HTML5 of YouTube player is compatibility with Android devices. When the user click the player to watch a video, no need to skip to YouTube App. Just embed and watch the video within the page, no Flash problems. At PresentationTube, we use HTML5 to allow mobile users watch the video within the page the same as the desktop.