[XviD-devel] [In progress] devapi4 -- mpeg matrices

[skal]

	Hi Edouard and all,

On Wed, 2003-11-26 at 17:50, Edouard Gomez wrote:
> Edouard Gomez (ed.gomez at free.fr) wrote:
> > So i  think we should  just write the  MMX versions again.  XMM versions
> > should use  less registers to  allow matrix passing, a  complete rewrite
> > seems not to be needed. Now up to you, assemblers guys, to do your job.
> 
	oops... sorry for not answering, i'm somehow busy lately...

> sklmp4, do you mind  if i steal^Wuse it in XviD ?  Of course it would be
> GPL, so you have to grant us this license change.

	Sure, no pb. But beware:

	a) i'm not sure it's bug-free (especially the h263 (de)quant)

	b) It might take more time to adapt it to xvid than simply
	re-using the idea: if you can't pass 4 pointers, just pass 1
	pointers, with all the four matrices packed together
	sequentially. (That is: pass "Q[4][64]" instead of "Q1[64], 
	Q2[64], Q3[64], Q4[64]"). Another idea: precompute the matrices
	for the 31 possible values of Q (even lazily). Memory cost
	is not humongous, and it simplifies inner loops... 

> just a  bit complicated sometimes because
> of  the C++ readability

	my fault: i was too lazy systematically prefixing
	the internal attributes with a '_'.

	bye!
Skal