I'm on a pretty fast machine running latest Safari and you can tell the glow is behind the video because there's a half second or so lag between scene transitions and the glow changing to match.
var default_settings = { brightness: 2.7, saturation: 1.4, lamps: 5, block_size: 40, update_interval: 500, fade_time: 400 };
var default_settings = { brightness: 2.7, saturation: 1.4, lamps: 5, block_size: 40, update_interval: 500, fade_time: 400 };