11 Aug
2004
11 Aug
'04
11:07 a.m.
Rumor has it that der Mouse may have mentioned these words:
Just checking, but are we on the same page? If you're talking *music* then
I'd agree with you, but if we're talking computer "cassette audio data
storage" formats, then I would think 44.1KHz would be more than ample, as
standard (or even "data") cassette tapes had nowhere near this quality...
... and it's not like many people would just sit around listing to it on
their hi-fi... ;-)
What shall we
do with analog audio? Sample at 44.1KHz / 16-bit PCM
and call it done?
No! Please! Not for archival purposes! 44.1KHz is good enough for
casual listening, for most people, but it is not good enough for
archival - and for a serious audiophile, it's not enough even for
listening. Of course, this is a choice to be made by the person
converting the
analog data to digital. I think the format spec should be able to
describe whatever that person chooses; I think it would be a _very_ bad
idea to assume anything about what that choice will be. The format
should be able to handle anything from 3 bits/sample compressed sound
such as I get from my voice modem, or even less, to multi-MHz sample
rates at hundreds of bits per sample (8-eg, channel 32bpp = 256 bits
per sampling tick). For audio, you probably could get away with
capping it at a few GHz sample rate - I'm not sure air can carry
frequences that high - but I see no reason to impose any limit.
Well, maybe I'm wrong, but "audio" would assume "audible"... as in
you need
to be able to hear it. Standards say that would be 20Hz->20KHz, but I'd say
DC->25KHz would be better...
... If this archive data is to be around long enough that humans have wiped
themselves off the map, and dogs eventually evolve to sentience (assuming
they haven't already, and are taking the "perma-retirement" path to
enlightment... ;-) then DC->35KHz would probably be about right.
Altho I agree that we shouldn't "impose limits" - and the spec should
handle as much as possible, I would doubt that there's much analog data out
there that would exceed 100KHz; and for audio 35KHz would probably be the max.
YMMV, Salt to taste and all that jazz,
Roger "Merch" Merchberger
--
Roger "Merch" Merchberger | "Profile, don't speculate."
sysadmin, Iceberg Computers | Daniel J. Bernstein
zmerch(a)30below.com |