How it works
Choosing what to record
Press the button and your browser opens its own picker: a whole screen, one window or one tab. The page never sees anything you do not pick, and the browser shows its own indicator while sharing is on.
Stopping the share from the browser's bar ends the recording and keeps what was captured so far.
Sound
Sound from the screen or tab is a checkbox in the picker, offered by Chrome and Edge. With the microphone also on, the two are mixed into one track. Safari and Firefox share video only.
The file
The browser's recorder writes WebM (VP9 or VP8 with Opus) or MP4 where it supports it. The take plays back here before you download it, and Pause leaves out the paused time.
