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Old 10-16-2018, 12:36 PM   #22
karbomusic
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Quote:
Originally Posted by viscofisy View Post

There's a "blend mode" used in video/image compositing (the interweaving of pixel layers) called "Subtract". Justin's video is called "Subtraction" so I'm guessing that he used a Subtract mode to blend the layers -_
That should be correct or close, subtract is very well-known pixel blending algorithm. Often used in various ways, including motion detection (any pixels that differ between two frames turn white, same pixels turn black aka null for example assuming a motion detect algorithm), IOW, it's the pixel equivalent of an audio null test. Let's say pixel A has a value of 100 and pixel B has value of 100, then 100-100=0.

FWIW, the video processor preset subtract works this way IIRC so anything moving gets rendered, otherwise black, it's pretty cool looking actually, no need to listen, just look - it's from last year when I was testing reaper vid and a looper at the same time.



If two videos are overlayed, the black is probably just the underlying video content per Justin's demo - haven't tested though. I am pontificating some here but I think it's close.
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Last edited by karbomusic; 10-16-2018 at 12:54 PM.
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