When recording from the internet, I have left my PC to eat, when I came back the Audacity was still recording, long after the sound stopped. How do I set Audacity to stop recording after say 20 seconds of silence?
Audacity has Transport > Options > Sound Activated Recording.
Also in Audacity > Edit > Preferences > Recording, there is a slider where you can set the volume that the recording triggers. No delay options that I know of.
There is plain Timer Record where you set Audacity to record for a set time and then stop.
There’s also Truncate Silence. You can use that to slice off long chunks of silence in your production.