QTCoffee / muxmovie / -transparency-mode mode

$ muxmovie -transparency-mode help

Error getting transparency mode. Correct syntax is one of:

-transparency-mode none †

No transparency.

-transparency-mode straight-alpha †

Use the alpha channel that's in the movie.

-transparency-mode transparent red,green,blue †

The specified color is transparent; all others are opaque. red, green, and blue should be between 0 and 255.

-transparency-mode transparent16 red,green,blue †

The specified color is transparent; all others are opaque. red, green, and blue should be between 0 and 65535.

-transparency-mode blend red-prop,green-prop,blue-prop †

Blend the two images using the specified proportion for each channel. red-prop, green-prop, and blue-prop should be real numbers between 0 and 1.