[XviD-devel] GME and Block ME

Christoph Lampert chl at math.uni-bonn.de
Fri Apr 18 18:24:08 CEST 2003


On Sat, 19 Apr 2003, Radek Czyz wrote:
> Isn't that 'sum of absolute coefficients'? As far as I remember sum of
> absolute coefficients is the power of the signal, which is sse.

I may have comletely lost my mind, I am rather sure that DCT is just 
orthogonal in L^2-norm, so 

Sum-of-squared-values-before-PSNR = Sum-of-squared-values-after-PSNR 

but sum-of-absolute-values-in-image-domain (SAD) has nothing to do with
sum-of-abs-values-of-dct-coefficients. 

But maybe my caffeine-level is too low for this higher maths at the
moment.

gruel




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