I can't get the blue screen effect to work.
I add a clip of a white sofa in a white room with a green paper placed in the sofa in a video track.
I add a background clip in the video track below the first one.
I add a composite transition for the entire length of the two clips.
I add the blue screen effect to the top video track.
But no matter how I pick the green color from the green paper and adjust the variance I can't get it to work.
Sure, the underlying clip shows thru the top clip at some points but the areas have no relation to the green areas.