[XviD-devel] Scrolling motion problem..

[Michael Militzer]

Hi,

Quoting Michael Niedermayer <michaelni at gmx.at>:

[...]

> > The 'latest' ffdshow alpha is way too old. You need a newer version if you
> > want to continue to use ffdshow. Try one of the newer Athos builds:
> >
> > http://athos.leffe.dnsalias.com/
> >
> > BTW: imho the decoding quality of XviD files using the native XviD decoder
> > + postprocessing is better than using ffdshow (but ffdshow is faster,
> yes).
> > But all this surely is a matter of personal taste...
> could u elaborate on this? 
> are u saying that the postprocessing in ffdshow is worse then the 
> postprocessing used in xvid? if thats the case then the obvious fix would be

That would be my claim, yes. Last time I checked (december ;-)), XviD 
deblocking preserved generally more detail than ffdshow postprocessing (with
MPlayer method) while still filtering out all visible blockiness in flat
colored areas. But it may be a matter of personal taste how much detail you
like to have preserved. Also I have to admit that I noticed you implemented
some new postprocessing stuff into MPlayer last year that wasn't part of
ffdshow at the time I tested (and is maybe included now), so I can't tell 
for sure about the quality of the latest ffdshow versions.
 
> that someone ports the xvid pp code to ffdshow
> the mpeg4 decoding itself shouldnt look different as the spec requires it to
> 
> be binary identical except the IDCT, but IIRC (i dont use windows or ffdshow)
> 
> ffdshow supports the libmpeg2 IDCT which is AFAIK also used in xvid, so both
> 
> xvid and ffdshow without postprocessing should have binary identical output,
> 
> unless one is buggy of coarse ...

yes, idct is another source of potential problems: you're right that ffdshow
also supports libmpeg2 idct, but (at least last time I checked) the default
idct setting in ffdshow was simple idct. Of course, most people who just
like to watch some clip and install ffdshow for this, don't check the idct
settings right after the install and most likely don't even know that they
should switch to 'XviD idct' (as it's called in ffdshow) in order to have
best playback quality for XviD (and almost all other popular codecs). So I
guess most ffdshow users have the idct set to default (simple) and therefore
may experience sub-optimal quality when playing back XviD clips...

Michael