Lets you use alt and + or alt and - to change the playback rate of HTML5 video elements
An extension that lets you use keyboard shortcuts to control the playback speed of HTML5 audio and video elements.
Alt and + increases speed
Alt and - decreases speed
Alt and 0 resets speed temporarily
The speed is saved locally for each domain individually.
Visit https://www.youtube.com/html5 to make sure YouTube tries to use HTML5 video whenever possible.