[XviD-devel] Re: qpel smearing/noise problem

Radek Czyz xvid-devel@xvid.org
Thu, 9 Jan 2003 22:49:36 +1030


This problem is - obviously - not only related to idct.

However, the results are very strange:

When XviD idct was used, xvid could decode everything correctly, but
ffdshow with xvid idct - couldn't.

When 'simple' idct was used in xvid, ffdshow (with 'simple' or
'reference' idct) is able to decode H and V interpolation correctly -
but not HV. No other changes has been made to anything.
Does anyone has any explanation? There must be an explanation for
this...

HV interpolation wasn't decoded correctly in any case - using
reference idct, both in encoder and decoder, didn't help either.

Does anyone remember where can I find in the specs, what size of block
is used for halfpel interpolation in qpel mode? I've been doing all my
experiments both on 8x8 blocks and 16x16 blocks, simply because I don't
know which is correct. I'v been looking for it, but I havn't found the
answer.

Radek