ola,

>
>
> i would also be interested in which context "RGBA" is twice as heavy
> as "YUV" (with respect to Gem/pdp)
>
it's as simple as have shown dumb+dumber :

in RGBA format, a pixel is represented by 4x(data size)
in YUV planar 4:2:2 format, it is represented by :
1Y + 1/4*U +1/4*V = 1,5*(data size )

Technically that is 4:2:0. ;)

4:2:2 would be represent as 1Y + 1/2U + 1/2V in your notation. That is 16 bits per pixel or two in the 32bit space required for RGBA.

of course, loops are much faster with YUV 4:2:2

Just about everything related to video is faster with YUV processing. That's why both PDP and GEM have full YUV chains right?

cgc