Watch Faster optimizes your video viewing by allowing you to make quick playback speed adjustments, as well as rewind the video to hear the last few seconds one more time. We don't read at a constant speed -- we shouldn't have to watch at a constant speed either. With this extension you don't have to.
Once it's installed simply navigate to any page with a video, and you'll see a speed indicator in top left corner of the video player. Hover over the indicator to reveal the controls to accelerate, slowdown, or rewind the video (10 seconds + lowers playback speed). You can also use your keyboard:
S - decrease playback speed.
D - increase playback speed.
R - reset playback speed.
Z - rewind video by 10 seconds.
X - advance video by 10 seconds.
V - show/hide controller.
Don't forget to check out the settings page where you can customize all of these shortcuts and more.