Switch to Flash Player for YouTube for Chrome
More About Switch to Flash Player for YouTube
A comprehensive comparison about Flash and HTML5 players is presented in this (https://en.wikipedia.org/wiki/Comparison_of_HTML5_and_Flash) Wikipedia page. It compares the features of the Flash platform, the HTML5 specification and the features implemented in modern web browsers. For example: Flash player has a better Device support comparing to HTML5. It has a better Bitmap effects support. It also supports C++ language. Moreover it has a better Data compression support comparing to HTML5. Flash Player has the ability to specify measurements in sub-pixel increments. This can result in a crisper and generally more pleasant appearance of Flash web sites.
Note: Before using this Addon, please make sure your Chrome's Flash player is up-to-date: https://support.google.com/chrome/answer/6258784?hl=en
According to many Tech blogs, YouTube is slowly replacing Flash with HTML5 player for its default web player (specially Chrome's latest versions). Therefore, if you still want to use Flash Player for YouTube videos, installing this Addon is the best way to go.
If you see any Bugs, have a feature request or other suggestions, please visit Addon's Homepage (http://eccorem.com/apps/youtube-all-flash.html).