Linux作为USB UVC设备

Question

What is needed for making a Linux device (Raspberry Pi) behave like a UVC device for another computer? Essentially, I would like to use output from ffmpeg to behave like a webcam input for another computer.

Answer 1

What is needed for making a Linux device (Raspberry Pi) behave like a UVC device for another computer?

This can actually be done on the Pi Zero without a custom kernel. After setting dtoverlay=dwc2 in your config.txt for OTG support, reboot and run:

sudo modprobe g_webcam
./uvc-gadget -d

These are first steps to make your Pi behave as a webcam by streaming synthetic data, which you can test out in Skype, FaceTime, or other webcam viewers. Here is source for the uvc-gadget userspace program with its commonly recommended patches.

Essentially, I would like to use output from ffmpeg to behave like a webcam input for another computer.

This part could be more involved. The existing uvc-gadget program can supposedly play back webcam recordings captured via GStreamer, more discussion on that in this post . For arbitrary input to FFmpeg, you may have to integrate your own output plugin code with uvc-gadget.

If you go as far as using compression: note FFmpeg can already output mjpeg in various container formats, but that data would still have to be converted to the UVC payload mjpeg format.

Answer 2

You will roughly need an USB OTG capable RPi, the RPi 3 is not capable of that. Then you will need a custom kernel driver that emulates the UVC Driver of a real device, I am not aware of any project that does this directly.

The easiest way I can think of would be to stream the recorded images via RTMP instead of trying to emulate UVC as that is not a small feat.