One other note - it appears the video loopback module doesn't block the write, so the flashcam program runs continuously. It uses about 9% of CPU when it does. The red light is on continuously and it would be nice if it was only on demand.

Also it appears not to need the LD_PRELOAD and .so - but /dev/video0 will appear so you need to make sure you select the Video loopback and not the undefined device.