Re: [stella] music compression

Subject: Re: [stella] music compression
From: Chris Wilkson <ecwilkso@xxxxxxx>
Date: Fri, 2 Apr 1999 18:30:01 -0500 (EST)
> Hi all, here's my lastest puzzle:  I'm working on a four channel music
> engine, and I'm trying to work out some of the internal memory management


Have you considered creating your own waveforms?  This allows you to use any
frequency you want.  If you only update the sound registers once per line,
you get 0 to 15.7kHz, or 8 (resonable) octaves.  If you update every other
scanline, you get a top end of 7.85kHz...still not bad.

Also, let's assume that no voice ever jumps more than an octave.  If you
use relative motion, with chromatic scales, you need 3.5 bits of storage
for each voice, and you give each voice a total range of 4 octaves
(conservative 2-scanline approach).  Also, since (I assume) you're doing
2 voices per channel, if you're just re-writing the volume data for each
channel, you can store the information in terms of channels instead of
voices.  Doing this gives double the storage resolution, or 1.75 bits
per voice, per beat.

This all assumes infinite clock cycles with which to work.  :)  Right now,
I'm way too tired to do the math and get the *real* numbers.  But it might
give you a different way of thinking about the problem.

"So why didn't he try to give feedback before my engine was locked
in place!???"  - Andrew

Ok, I have to go watch TV.  But I'll think more on this and get back to you.


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