Is it possible to merge a video track with a canvas track?

[marcusx2]

Please see this SO post. You can record a canvas with the microphone. I got that working. Is it possible, however, to record a video and a canvas simultaneously, where the canvas overlays the video? The video will be the camera feed, and the canvas will have other stuff that will overlay the video. I was wondering if I could use the MediaRecorder to do this, just like it's possible to simultaneously record the canvas with microphone input.

Thank you for your time.