Upgrade for Pi OS

[DevelopDaily]

Summary

Upgrade for Pi OS

Motivation

Has anybody planned to upgrade the project for the latest Pi OS? Raspberry Pi has upgraded from Raspbian to Pi OS. They said they would discontinue the "Legacy Camera", which pion/mediadevices relies on right now, in the future.

This project is so useful to the Raspberry Pi ecosystem that a thorough upgrade for Pi OS would benefit a lot of new apps.

Right now, the webrtc example does not work on Pi OS. I have to rebuild the opus library to make it work.

Describe alternatives you've considered

As I stated above, the "Legacy Camera" must be enabled and some libraries such as opus must be rebuilt.

[bprfh]

The problem is that libcamera doesn't present a v4l2 device, libraries are expected to call the c++ api.

To support older v4l2 based programms you can use libcamerify which uses LD_PRELOAD to hook the open and v4l2 libc syscalls.

This doesn't work if you use the go builtin syscalls as these use assembly to directly call in the kernel instead of using libc.

The solution is to use cgo and use a bridge function for open/close/v4l2 syscalls and run the progamm.

I have implemented a new package which uses a cgo and works with libcamera, but I'm not ready to upload it yet.

You could also replace the ioctls with cgo code in the blackjack/webcam package.