[XviD-devel] Quantization

[Edouard Gomez]

No one to answer that simple question ?

At  least the  LUT idea  seems to  be good  for h263  (the LUT  would be
something like 2*32*2048*2=256kB

mpeg4 has  the disavantage  to require much  more memory because  of the
quantization matrix but current  implmentations are quite ugly requiring
global matrices.

I can see problems even when using the decoder and the encoder at the
same time for mpeg4 quantization matrices:
 1/ read a movie "m" with a given quant matrix M1.
 2/ encode the decoded movie "m" using a quant matrix M2.

This currently  results in a  race condition on  what matrix is  used in
core. 

I'm currently  working on making  a DSP structure that  would centralize
all machine specific  code, perhaps it would be a  good moment to revamp
the  matrix  system  and  make  it  really  safe.   Afaik,  mmx/xmm/3dne
functions do  not leave  many registers to  receive the  matrix address,
I'll have a look after the DSP system is ready.

-- 
Edouard Gomez