I just need to see video output from android phone at my desktop over usb. I’d prefer something light. Must be libre. My mobile phone doesn’t have google services and I do not want to install a proprietary program like droidcam when I am giving permissions such as video and audio.
edit: Running android 11 and given permission to device to be controlled by desktop with adb already.
edit1: No bloated, shi**y, ad riddled programs pls.
Hey Liveline, welcome to the forum 
Interesting question! Was looking for almost exactly the same kind of solution you are looking for last year. The only requirement I didn’t have was that it has the be libre. Have not found anything that works, and the use case I had no longer exists. The one solition I remember that did not have any apps in between was a solution that ran a script on the phone that made photo’s and streamed the photo’s as a video. Fun solution for a security cam, not for video conferencing. If you find anything that works I’d be interested in it.
Maybe you could use scrcpy to somehow achieve what you want. However, it probably isn’t the solution you are looking for.
Hello @liveline and welcome 
I don’t think you will find anything under your conditions… at least the client for droidcam is open source on linux. It is easier to develop it yourself than searching for this simple piece of software… 
Have you seen 
it is in the tutorial section.