Do you find it annoying when you open a web page, and it plays automatically those HTML5 videos. If you enable the Auto Stop feature in the Turn Off the Lights browser extension, you don’t have this issue anymore. Because in Turn Off the Lights browser extension v3.1 or higher stops all the HTML5 and YouTube videos on that web page.
How enable this feature for all HTML5 Videos?
To use this feature open the Turn Off the Lights options page. And make sure you are on the “Basics” tab page, below the preview window you see the ‘Autostop’ feature. Enable the checkbox and restart your web browser.