[XviD-devel] [RFC] Decoder speedup

[skal]

	Re,

On Mon, 2004-06-14 at 18:01, Michael Militzer wrote:

> > 	What is the average quant of your bitstream??
> > 
> > 	Because there's a big difference between ffmpeg and xvid:
> > 	ffmpeg is dequantizing the coeffs on-the-fly, so that
> > 	this operation scales as the number of non-zero coeffs.
> > 	XviD, contrary, dequantizes every 64 coeffs with SIMD.
> > 	It's faster, but inefficient if only few coeffs are
> > 	non-zero.
> 
> Skal is right - 


	well, not quite: i've just cross-checked and it
	seems it's only used for h263 dequantization method,
	but (maybe) not for mpeg4 dequant method. Anyway,
	you get the idea. Note that mpeg2dec also uses
	on-the-fly dequant.

	bye!
Skal