Re[2]: [XviD-devel] xvid + bframes and mplayer/ffmpeg decoding

[Christoph Lampert]

On Fri, 16 Aug 2002, Michael Niedermayer wrote:
> [...]
> > And, of course the "DCT!=0 -> iDCT==0" thing... Maybe we should simply
> > disable quant=1, I guess then the problem would be more or
> > less solved... ;-)
> i thought about the same for ffmpeg ...
> btw, an alternative is to drop blocks with only a few +-1 coeffs 
> and 0 for the rest (this seems to solve the issue with 1 test file 
> and ffmpeg as encoder)

THAT of course would only be a few bitflips in XviD code ;-) 

It is clear from anything that e.g. if one (quantized) coefficient is 
2 that this will never lead to iDCT==0, even for quant=1? 

What about one _dequantized_ coefficient of 2? If I remember correctly, a
peak error of 2 was allowed for something...

Actually I have no idea what quant=1 really does.

gruel

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