Subject: Re: /dev/audio works, (SPARC)tracker not
To: Timothy Newsham <newsham@wiliki.eng.hawaii.edu>
From: Geert Uytterhoeven <Geert.Uytterhoeven@CS.kuleuven.ac.be>
List: amiga
Date: 12/12/1994 10:12:45
> > Just a suggestion: Why not using 2 channels to play u-law encoded sound?
> > That way you can use one channel for 8-bit samples and the other channel
> > to modulate the volume (6-bit) to achieve a net result of 14-bit (= full
> > u-law linear range).
>
> Strangely enough I was thinking about this and wondering if it was
> possible, and if so, how practical it was. Using volume to modulate
> might not get you 12 bits. There 8bit data and 6 bit volume but
> many of the combinations of A x B are repeats, and not all values
Oops, I forgot that. But it's definitely suited for u-law, since u-law
works that way (piecewise linear approximation) and so all required
values are possible.
> can be obtained with A x B. (btw. volume x data just takes one
> channel, but the hardware does support modulating one channel with
> another I believe, that would give you 8 bits each right?)
> I guess its well suited to mu-law though since there are many
> 12-bit combinations that are not represented by 8bit mulaw codes.
> This might work nicely but it would eat up all four of your channels
> for stereo output. I might look into this further later on as
> an optional setting.
>
> btw. has anyone done this before?
There was a discussion about this on comp.sys.amiga.programmers some
weeks ago. I thin to remember there were some players on AmiNet that
use this trick.
Greetings,
Geert
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| Geert Uytterhoeven -->> Wavelets, Amiga, MultiUser, Linux/68k,... |
| Geert.Uytterhoeven@CS.kuleuven.ac.be |
| Dept. of Computer Science, Katholieke Universiteit Leuven, Belgium |
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