ondataavailable stops firing if interval small (<500ms) and finger is placed over webcam

[graeme44]

This is super strange, but please test it out: Using this demo:

1. Set the interval to 500ms
2. Click start
3. After a few seconds press a finger to the webcam -> The ondataavailable event stops firing (the append links stops)

Is there any good reason why this would be happening? I've been considering the min frame rate but this doesn't seem to help.