[vorbis-dev] equalization

[Beni Cherniavsky]

On Thu, 24 May 2001, Robert Voigt wrote:

> On Wednesday 23 May 2001 00:03, rodolfo.borges at mail.com wrote:
> > what about adding equalization in the decoder?
> > it makes sense doing it internally because the sound is stored
> > in the frequency domain, like mp3, right?
> 
> I think it's possible, but if the decoder is a media player that plays all 
> kinds of formats including wav and audio CD you still need to implement the 
> usual digital filters for equalization. For Vorbis you'd save some CPU 
> cycles. I'm not sure if it's worth the trouble.
> I once had the idea that I could use the frequency domain data of Vorbis for 
> visualization. This way I could save the CPU cycles for the FFT. This makes a 
> little more sense than using it for equalization, because those fancy 
> visualizations need a lot of CPU and a little more power would give some 
> extra fps. Moreover, I could make a certain event happen in the visualization 
> whenever there's a short block, assuming that the short block was triggered 
> by an attack (or maybe a beat?). Perhaps those sounds that trigger short 
> blocks make you feel like jumping or something, and it would be nice to 
> express this in the visualization.
> Can anyone comment on this please? 
> 
The winamp plugin interface provides for the plugin doing EQ and/or
supplying spectrum data.

Segher says MDCT is very different from FFT -- is it good enough to
cheaply produce vis data as a side effect of vorbis decoding?


-- 
Beni Cherniavsky <cben at crosswinds.net>
                 (also scben at t2,cben at tx in Technion)

10001110111100111100001001010 m/s

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