Mask a HTML5 video

I would like to mask a HTML5 video element and convert it into a triangle. I want a solution that will work in IE9, Fir开发者_Go百科efox and Chrome. Is it possible?

I'm not sure how cross-browser compatible this is but I know that Apple has a Safari Technology Demo where they use -webkit-mask on an HTML5 video. It might be worth investigating.

You can mask videos using SVG in Firefox, but that won't work for IE9 or chrome. You could copy the video frame by frame to a canvas element and then manipulate the video there to create a Mask effect. Using just CSS though it is not possible as far as I am aware.