Compositor clipping blurred matte nodes I am trying to add a vignette to a video clip, something I have done hundreds of times before, but my ellipse or box mask keeps being clipped by some setting that I can't find. It is only allowed to blur within a certain area, after that it is clipped sharply.



Any ideas what might be the cause of this?

I am using Blender 2.74, and no other parts of the compositing nodes have an effect.
What is happening is the blur node is using the render result size to determine the blur. What you need to do is set the render size to the same size as the footage:



Once this setting is set it should render correctly.