The audio CD is a fascinating little creature, to us, anyway. Keep in mind we're kinda weird, according to relatives, friends, and loved ones. Bob, for example, on seeing Figure 1.1, shook his big booty but good, and started singing the words "Rock Lobster" in a castrato falsetto that caused Josh's ears to bleed.
In terms of how CD-Audio data is written and read, it's nothing like a CD-ROM, or a DVD, or anything else for that matter. There's a very specific format for CD digital audio, described in a technical document called the Red Book. Ironically, this particular Red Book was not written by Chinese communists; it was written by Sony and Philips. It's an incredibly boring read, so, if you're going to read a Red Book, we suggest you read the one by Mao Tse-Tung instead.
We'll begin with the easy stuff. We'll show you how to rip tunes that already accord with the CD-Audio standard, that is, tracks that are already on CDs. (See Chapter 3 for that.)
Next, we'll move over to the Internet, where music exists in abundance but must be altered in some fashion or another before it's ready for CD-R. (It's not at all complicated, so have no fear.) For example, if you wish to capture your favorite Internet radio station's Reggae Hour, we'll show you how to record it to your hard disk, transform it into "data" suitable for CD-Audio, split it into tracks, and burn it to CD-R. (See Chapter 5 for that.) MP3s, too, receive no small treatment in Chapter 4; there, we'll show you how to "decode" an MP3 so that it may be burned to CD.
After that, we'll show you how to "digitize" cassette tapes and records, so that they may be restored, preserved, and enjoyed. Things get slightly more complicated there, but, again, it's not quantum physics. (Or, actually, it is, but you don't need to know anything about quantum physics to restore your records and tapes.) The only new issue that arises is you'll be working with analog material, and, consequently, you'll need to make a couple hardware connections so that the analog material can be digitized, edited, sweetened, and split.
Interesting Stuff You Don't Need to Know
The Red Book sets forth two standards for CD digital audio: one for structure and one for content, known as "physical" and "logical," respectively.
The logical standard of the Red Book sez:
Your "data" (music) must be nabbed via PCM. PCM (Pulse Code Modulation) is a means devised to represent analog materialsuch as a live jam sessiondigitally, that is, transformed into the 1s and 0s of binary.
Your data must be sampled at 44.1 kHz. That means 44,100 "listenings" of the band's live jam are taken every second. We'll go into more detail about these "listenings" in Chapters 6 and 7, where we actually digitize analog material.
Each sample must consist of 16 bits, which is binary information about what the "listening" heard during sampling. This is where the analog material becomes digital material.
This binary information gets "demodulated," or translated, back into analog in what's called a "pulse code demodulator," which, in this book anyway, is a fancy way of saying CD player.
A PCM 44.1 kHz, 16-bit item goes by *.wav on a PC and *.aiff on a Mac, with the asterisk standing in for whatever the tune is called. What we're going to be doing in this book is either extracting or decoding WAVs and AIFFs from digital sources, or actually making WAVs or AIFFs from analog material, specifically, your records and tapes.
The Red Book, named for the color of its binder, was followed by several other CD books (not necessarily in chronological order here): the Yellow Book (CD-ROM specs), the Orange Book (CD-R specs), the Blue Book (Enhanced CD specs), the White Book (VCD specs), and the Green Book (CD-i specs, if anyone remembers that miserable failure of an idea). In this book, we'll be treating of the Red, Orange, and Blue books.