This project has been superceeded by VideoScan https://github.com/dkloke/videoscan which has more features.
by Dan Kloke ©2019 - MIT / Google
from a tweet by @kentcdodds
This extension looks for all <video> elements on the page, and adjusts their playback speed (.playbackRate) simultaneously for all tags on the page.
Adjust video playback rate using ↑/↓ cursor keys, a mouse/touch interface, or manual entry.
The app does not send any information to the developer, and only stores user preferences locally. VideoSpeed makes no effort to be compatible with on-page code or other browser apps.
Repeated speed adjustments can cause video players to lose audio synchronization. To recover audio sync, try skipping forward/back or adjusting the video's replay position, stop and restart the player, or reload the page.