[XviD-devel] MV-clipping problem?

[skal]

	Hi Radek,

On Fri, 2004-02-27 at 05:46, Radek Czyz wrote:
> Skal wrote:
> 
> > 	Radek: attention! These are not "broken" bitstreams, but rather
> > 	"stress" bitstreams. The dMVs are perfectly valid ([-2048,2047],
> > 	with fcode=7), yet perfectly non-sense.
> 
> Okay, I'll implement clipping now. How should it work? Do we assume that 
> edges go to infinity (so I just clip to valid range, which is 16 
> fullpixels outside of last macroblock) 

	That's it (see 7.6.4).

	Note, however a peculiarity:

	"A bounding rectangle is defined by vop_width and vop_height
	extended to a multiple of 16".

	While *decoding* a picture with strange dimensions (not
	multiple of 16), this has an impact on where to start
	replicating edges => at the next multiple of 16, and not
	the pic's dimensions.
	For encoding, there's no such trap: you're on your own to
	replicate whatever you want wherever you want.

	bye!
Skal