Re: 24-bit wav files and other observations

[Przemek Klosowski]

   Well, probably few general-purpose systems.  There are many 24-bit
   embedded processors, of course, and then there are plenty of data
   files that use 24-bit data.  So, from an analytical standpoint
   there are reasons for having 24-bit "native" types.  It's similar
   to the situation that we have very few 8 bit CPU's anymore, but the
   8-bit width "native" format is still ubiquitous.

Actually, most of the CPUs in existence are 8-bit; they are in your
consumer appliances, calculators, cars, watches, etc etc. The
prevalence of 8-bit data types has nothing to do with those,
though---it just happens to be a convenient size with granularity almost
right to encode most human-language communication, and a lot of data
if the required accuracy is not better than 0.4%.

If the 8-bit byte is ever dethroned, it will be by internationalization
(Unicode characters) and by the fact that control loops for things
like motors, actuators, etc. barely work when the signal to quantization
noise ratio is 24dB (8-bit data) and really prefer 36 dB (12-bit data) or
48 dB (16-bit data).

24 bit data is in the area of diminishing return: for 33% more space
(32 bits) you get a dynamic range hike from 72 to 96 dB, and you don't
have to deal with unaligned loads. Even in graphic cards, where
essentially one throws away the fourth byte (bits 25-32), the 32-bit
pixel is often used rather than the 24-bit pixel, just to make data
moves easier.