blind-set-alpha - Multiply the alpha channel of a video
blind-set-alpha [-i] alpha-stream
blind-set-alpha reads a video from stdin and a mask video from alpha-stream. The video is printed to stdout, with each alpha value multiplied by the product of the luminosity and the alpha value of the corresponding pixel and frame in the mask video.
If stdin is longer than alpha-stream, the remainder of stdin is printed without any changes. If stdin is shorter than alpha-stream, the remainder of alpha-stream is ignored but may be partially read.
Use the inverse luminosity of the mask video instead of the luminosity. It is still multiplied by the alpha value.
blind(7), blind-single-colour(1), blind-dissolve(1), blind-arithm(1), blind-set-luma(1), blind-invert-luma(1), blind-set-saturation(1)
Mattias AndrÃ©e <[email protected]>