In article ,
Henri Derksen  wrote:
>I understand, and I did know that kind of wrong input selections.
>But the Pi 4B has no audio input on the MoBo,
>only a socket for an extra camera on a flatcable, which I do not have.
>The most logical idea could be that Raspbian Buster Linux does not have a
>USB2A mic audio in software module, and can only work with the camera on
>the motherboard socket if connected?

The Raspberry Pi cameras don't have microphones.

On a Raspberry Pi 3 connected to one of my 3D printers, I set up a Microsoft
LifeCam HD-6000 for monitoring the printer.  It has a microphone, and poking
around in alsamixer reveals that it's showing up as an input device.  lsusb
shows snd_usb_audio in use.

It works pretty well at streaming 720p video from my printer, though I
should probably look into switching it from autofocus to manual focus as it
sometimes gets confused.

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