Can't hear internet video sound

I can hear Internet originating sounds and music played via mpg123. Various online radio stations. I can play all locally saved music using moc (music on console). I get sound from all movies on my hard drive viewed with smplayer or vlc. But I don’t get sound when playing videos using Firefox, Vivaldi, Brave, or Opera. Has Youtube restricted me or am I missing an add-on that affects all four browsers?

Thanks for any advice.

Missing a codec? Review the multimedia guide perhaps.

Yes, the standard question is always: did you do the vendor switch to Packman after all those installations?

Working with Firefox and pavucontrol I noticed that Firefox was set to use HDMI on playback which I have never set. Setting it to Analog Stereo solved my problem but only for Firefox. I had to individually set the other browsers from HDMI to Analog Stereo. I am curious as to how they were all simultaneously assigned to HDMI but had to be re-assigned one at a time.

Thank you for the suggestions.