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 )
of course, loops are much faster with YUV 4:2:2
i like the way people always argue here.
sevy