[PD] mask videos

[Andres Cabrera]

chris clepper wrote:

> Two things about [pix_coloralpha]:  One, it does nothing on YUV data.  
> Two, it just averages the R,G,B values, which really doesn't 
> correspond to anything useful.  In other words, drastically different 
> colors will give the same mask, and the only really useful values are 
> full white or black (the only unique ones when averaging). 


That's right, [pix_coloralpha] is mostly useful to create a mask with a 
black and white (greyscale) image.


Andrés