Til yesterday I used Jitsi meet with Electron and Chromium browser and with Firefox browser. The webcam was a Logitech C270.
Now I changed to Logitech C920 because of autofocus and better low light abilities. And then the problems started:
In Firefox I can allow / activate the webcam and its microphones and can choose between webcam microphone and another USB-microphone. Any test connections via Jitsi-meet were successfull.
In Jitsi meet electron and in Chromium, the webcam can be activated but there is no microphone to choose.
In both cases, I get an error message, that the microphjone is not accessable.
I have checked the webcam and its microphones with the program Guvcview and it showed up no problems. Further all system checks showed, that everything is OK and well working.
Any helpfull hints are welcome to solve this problem!