getusermedia screenshot wrong size
The drawImage API is really poorly documented and has a confusing way of handling arguments. Because of this sometimes if you capture a screenshot from your webcam the capture / snapshot will be drawn with the wrong dimensions. To solve this you will need to redraw your canvas to the same size as your video input on capture and also specify the width/height on capture.
This tripped me up for a few minutes so I figured it was worth documenting..
[html] <!DOCTYPE html> <body style="margin:0;padding:0;font-family:Arial"> <video id=”video” autoplay width=100%></video>
</body> </html>
[/html]
To test go to your development console and type “snapshot()”