This blur filter gives instructions of how the blur should be applied onto the symbol/frame.
staticread onlyBLX:Float
The amount of blur horizontally.
staticread onlyBLY:Float
The amount of blur vertically.
staticread onlyQ:Int
The number of passes the filter has. When the quality is set to three, it should approximate to a Gaussian Blur. Obviously you can go beyond three, but it'll take more time to render.