Stop Media On Lock is a free Chrome extension developed by Łukasz Gruszka. Designed specifically for Chrome OS, this extension automatically stops any playing media when the screen is locked.

Once installed, Stop Media On Lock waits for the screen to be locked and then proceeds to iterate through all the open tabs in the Chrome browser. It achieves this by employing two methods to stop media playback. Firstly, it iterates over all audio and video elements on each tab and calls the "pause()" function to halt playback. Secondly, for tabs with active audio but no audio/video elements, the extension sends the "space" key to simulate a pause command.

With Stop Media On Lock, users can ensure that their media playback is automatically paused whenever they lock their Chrome OS screen. This can be particularly useful in situations where privacy or conserving system resources are a concern.

Please note that this extension is specifically designed for Chrome OS and may not be compatible with other operating systems.