Browser is Firefox. I had made an icon on the screen from the address of Youtube, and it was working, but stopped. I did suspect Pulse Audio, so I followed the previous advice and installed pavucontrol. Opened up
the Youtube icon again, and the PAVUcontrol, and found that in the Playback box, AudioStreamServer: Audio Stream was set to 0, so moved the cursor in it to about 60 % and got good audio from Youtube. However,
when the particular segment of the stream played to the end, the sound stopped again, and the slider was back to 0. This is a pain! I wonder if there is any way to make that performance stop, and leave the slider at
whatever point I set it all the time?
Thanx for the advice!
–doug