[vorbis-dev] 2d wavelet transforms

Gregory Maxwell greg at linuxpower.cx
Sat Dec 30 11:57:00 PST 2000

On Sat, Dec 30, 2000 at 10:15:18PM +0330, jsr at dds.nl wrote:
> Oh, and another question I just remembered: audio signals 
> are signed, because they're representations of the movement 
> of the microphone. Video data does not have that, but the 
> wavelet transform does expect signed data (or doesn't it? 
> Haar works on unsigned data but what about Daubechies and 
> other wavelets?). So how do I convert? Simply subtracting 
> 128 from each sample (ie casting to signed int) seems wrong.

Your input does not need to be signed. 

I would scale my input to be 0.0 .. 1.0 and degamma it in the process. (So
that .5 is half bright to the viewer).

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