Android as an UVC Camera

Question

I'm stuck at home with a rather bad webcam. I was considering upgrading, but then it struck me: phones these days have really good cameras embedded in them. So why not use it as a webcam?

However, as I was researching this further I was really disappointed with the available apps for this. As far as I was able to find, we have Android apps that work roughly as follows:

• Present phone camera as a network attached camera. Then you can use local software to use that feed as a webcam. See e.g., IP Webcam. This may be sufficient, but it's a complicated setup, and network latency makes this far from ideal.

• The Android app sends the camera feed to an custom host application that in turn creates a virtual web camera. See e.g., DroidCam. This mostly solves the latency problem, but it is still rather complicated, and requiring us to install a specific third party application is troublesome in regard to user privacy. Especially since the applications are closed source.

So, I took the engineering approach and tried to see if it was even possible to improve the situation. As far as I was able to find, Android supports being used as a custom USB accessory. And looking over the USB video class documentation, it strikes me that it should be possible to create an Android app that presents the phone as a generic UVC webcam, such that we do not have to resort to tricks such as the ones above.

Ideally, I would have liked Android to add another USB device option ("Use USB connection as webcam") in addition to debug mode, file-transfer, etc. This seems quite unlikely to happen in the short term however.

So, my question is this: Does an application that does the above already exist? My searching thus far haven't yielded any results, but I might be missing something as googling for this turned out a bit harder than I expected.

Alternatively, am I wrong in my assumption above, such that there is some fundamental issue why an Android application cannot be made to work in that way?

Answer 1

There does not seem to be any complete app yet as of 2020-10, but the parts are mostly there:

• https://github.com/tejado/android-usb-gadget has code to switch the Android device into gadget mode (but no UVC yet)
• https://git.ideasonboard.org/uvc-gadget.git feeds v4l2 into the uvc gadget output

Sources:

• http://www.davidhunt.ie/raspberry-pi-zero-with-pi-camera-as-usb-webcam/
• https://www.raspberrypi.org/forums/viewtopic.php?t=148361
• https://www.reddit.com/r/androiddev/comments/iabc2o/can_i_use_my_android_as_wired_camera_ie_as_a/g1nrijl/