How to emulate camera input in Android? (To activate Whatsapp Web)

I have an Android device without a camera and I run Whatsapp on that device. I want to activate Whatsapp Web from this device. Unfortunately, the only way to do this is to scan a QR-code, and I can't do that as I have no camera. So, if I just could emulate camera input, that means use an image or video file of the QR code and have that be taken by the OS as camera input, then I would solve the problem. This is doable on Windows. I'm sure it should be doable on a rooted Android device as well, especially if we can use Xposed Framework. But the question is, does anybody know how to?