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Re: OT question about sound cards/chip-sets and high-end music systems



On Monday 05 October 2009 13:20:14 Johannes Wiedersich wrote:
> Boyd Stephen Smith Jr. wrote:
> > It is purely digital.  16-bit (not sure if this is floating- or
> > fixed-point), stereo, 44.1 kHz samples, IIRC.
>
> What's the difference between 16-bit floating-point and 16-bit
> fixed-point? I always thought those are just integers.

Some audio codecs use floating-point, which is like a "float" or "double" or 
"long double" in the C programing language.  Some bits are the exponent 
(usually with a bias) and some bits are the mantissa.  Other audio codecs use 
fixed-point, where the 16-bits simply a signed integer (or possibly an 
unsigned integer modified by a bias).

I think CDs are fixed-point, but I'm not entirely sure on that.  Both fixed- 
and floating-point have advantages, and I know various audio formats and 
programs use both.

8-bit fixed-point unsigned has exact values for [0,1,2,...,255]
8-bit floating point unsigned might have exact values for [0,1,2,...,63], 
[64,65,66,...,127], [128,130,132,...,254], and [256,260,264,...,508].
-- 
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