19th August 2009 16:39 UTC
Masking trick
If you open the attached example, you will see a white MP chasing a black MP. If you select Video Delay, the black MP is gone and notice that the MP is actually blue.
What happens :
The black MP is the buffer of the MP in the last frame, multiplied with infinity to make sure it's white, and then substracted from the background - masking the bg for the MP which is set to Additive.
The new frame (or better: the effect list) then is rendered, sent to the buffer, and after that, delayed with one frame to make it fall over the or mask.
This issue is probably as old as the APE itself, but somehow I missed the solution for it, I also couldn't find the solution by searching...
The problem lies in a bug in VD if I remember correctly (and see) - until you select the VD, it holds 10 frames regardless of what number of frames you have entered.
Does anyone know of a solution for this?