[XviD-devel] image pre-processing

[Christoph Lampert]

On Thu, 5 Dec 2002, Marc FD wrote:

> > I'd say, prefiltering is _not_ an integral part of the encoder,
> > it should be separate code, a separate imageprocessing library.
> > Much code for this is already available under GPL.
> >
> > But the encoder could contain some pre-processing and post-processing
> > options, too, which should be done as calls to the imageprocessing
> > library.
> >
> > That way, we don't need to invent the wheel for the 10th time, and still
> > can use internal data structures to control pre-processing parameters.
> 
> okay, that's why i asked.
> 
> i'm mainly interessed in encoder-dependant prefiltering, and you can't make
> that an external part of XviD, because it doesn't exist and is deeply
> related
> to the encoding process.

That depends... e.g. the preprossing lib could contain a routine to
smoothen the image at different strength for every 16x16 block (just an
example). Then the codec would just have to fill a data table and call the
external routine. 
Of course, the same routine could be interesting for MPEG decoder output
postprocessing, so a video player could fill these values as well and call
the same routine.

Or it could contain a routine for coefficient threshholding of DCT data. 
Not XVID dependent, but e.g. useful for JPEG encoding, too. 

gruel