How to implement getting video frame pixel data with CORS in mind?

Question

Canvas

I am writing an extension for styling VK. One of the extension's functions is to detect dominant background colors for further use in GUI styling. The background is loaded from a link to an image or video. Due to the fact that the request for the image was made from the VK domain, I could not access the pixel data of the image drawn on the canvas. To get around this limitation, I received an image from the background page with an ajax request, after which I converted it into a data url - which I drew on the canvas.
With images, this approach is quite tolerable, but with videos - not so much because of their size.
Are there any methods (other than those described) to get the pixel data of a video frame?