* las <[EMAIL PROTECTED]> on Sun, 30 Apr 2000
| Compression as I understand it is an encoding and decoding process.
| Anything that is compressed will have to be "decompressed" in order to
| play it.
CD-DA has this thing called a digital to analog converter for playback. So
if analog to digital is compression then digital to analog is decompression.
| Also, compression is almost always a lossy technique. When you decode
| (even though the human ear may find it next to impossible to distinguish
| between the original uncompressed source and the compressed copy) there
| is something missing from the compressed version.
Actually, no, it isn't. Lossless data compression has existed since, oh,
1960 or so, "lossless" meaning that what comes out of the decompressor is
identical to what went into it. Lossy compression is relatively recent,
1990 or so, "lossy" meaning that what comes out of the decompressor is not
identical to what went into it. ZIP is a lossless compression scheme; JPEG
is a lossy compression scheme.
| Since if you cut the frequency response off at a certain point and can
| never recover the sounds above that frequency response, that is not
| compress. Compression allows you to recover a facsimile of the original
| source. Just how different that is depends upon how lossy the technique
| is.
In what way is this facsimilie reproduction different from an audio CD
compared to the original analog source? Because that is what you are
getting out of the player: a facsimilie.
[...]
| I suppose that if you wanted to, you could cause anything that reduces
| the amount of information from the original source a form of compression.
Bingo!
| But in the terms we think of it today (and the definition that I accept
| (for what ever my opinion is worth) the term compression means encoding
| and decoding.
How is converting an analog signal to a digital data stream different from
"encoding"? How is converting that digital signal back to analog not
"decoding"?
| MP3, ATRAC are compression techniques.
Technically, ATRAC is not a traditional compression algorithm, but bitwise
reduction. But we call it "compression" anyway because the end result is
to make the data smaller. MP3 combines bitwise reduction and Huffman
coding (a lossless compression scheme).
| Cutting frequency or limiting the difference between the quietest and
| loudest sound is not in my opinion what we think of today when we speak
| about compress (although in the broadest sense removing or limiting
| anything probably could be called compression-I just don't think it is in
| common usage of the word today.
But that is what ATRAC does, and we call it compression. So it is common
usage even if most people do not relize it.
| Well sorry for all of the bull sh*t. Please don't spam me. If I have
| made any errors of fact, please correct me. If you have differing
| opinion, express it, but please don't spam me. In areas that are
| subjective everyone is entitled to their opinion.
No shit. The point I am trying to make is that just because we might not
call a duck a duck doesn't mean it isn't a duck. At least I made you
think about it.
--
Rat <[EMAIL PROTECTED]> \ Do not taunt Happy Fun Ball.
Minion of Nathan - Nathan says Hi! \
PGP Key: at a key server near you! \
-----------------------------------------------------------------
To stop getting this list send a message containing just the word
"unsubscribe" to [EMAIL PROTECTED]
