There is a 'requestAnimationFrame' loop and every frame the HTML5 video will be uploaded via 'texImage2D'.
When the video will be paused, there will be no video uploads but the WebGL will keep rendering.
To see that something is rendering there is a hue-rotation effect.
On iOS 8 beta 4+5 and also in the OSX 10.10 Safari the video texture uploads are way too slow!
There is probably a slow GPU-to-CPU-to-GPU path for the video frame here...?
Test notes - press 'Pause' to see the FPS increase due the paused video!
There are no 'texImage2D' calls when the video is paused, but WebGL itself is still rendering every frame (hue-rotation effect).