Redbook Format - Compact Disk Digital Audio
This was the first data standard for CD's and it was only capable of storing audio information. It is
named "redbook", because the specification was initially presented in a red colour binder, and the name
stuck. It was first introduced in 1980 by Sony and Philips. This is the most important standard,
because it is the standard used on ALL audio CD's. Every CD device ever made; wether it is a audio
device, game console, or data CD reader; is capable of reading Redbook format CD's. All audio is
recorded at 44.1KHz with 16bit samples as part of what are known as tracks. According to the
Redbook standard, up to 99 tracks can be stored on a single CD. Redbook defines a Volume
Table of Contents (VTOC) which contains information that identifies the CD's data as audio
information, track numbers and lengths, and how to read it.
The format for a Redbook CD is that the CD is divided into 3 basic parts, the lead in, program, and
lead out. All VTOC data is stored in the lead in part. The lead out is simply blank information to let
the CD player know that the data is finished. All real data is stored in the program section of the CD.
Data is stored in small blocks know as frames. Each frame has 24 bytes of user data, along with
synchronization, ECC, and display bits. These small frames prevent scratches from damaging more
data than is should.
To extract the audio information off of the CD, the device identifies the CD as a Redbook audio CD by
its VTOC. Data is read off of the CD in binary form and passed through a simple Digital to Audio
Converter, which converts it back to analog form. Audio information is less likely to malfunction,
because audio is a waveform, and therefore predictable, the DAC can fill in areas were information is
unreadable or corrupt. This allows even most scratched CD's to be playable without static or fuzz.
Data Standard ISO 9660 Format
This CD format was the first standard that could store data. It also extended on the Redbook format
adding some features to basic audio recording. This format was introduced by Sony and Philips, and is
also known as the "yellow book" standard, a spin off of the audio format "Redbook". It simply expands
the Redbook format to be able to store data, its still uses lead in, program, and lead out areas, along
with frames and simple ECC. What it does is group 98 frames together to from sectors. Each sector is
given 288bytes of ECC code, 12 bytes for internal synchronization, a 4 byte header and a total of
2,048 bytes for actual data. All sectors are recorded in the VTOC by their (Minutes:Seconds) location
on the disc.
Mode 1 is the basic YellowBook format, and Mode 2 is different version. Mode 2
still uses the same structure as Mode 1, except all ECC information is removed, allowing the capacity
of each sector to increase from 2048 bytes to 2336 bytes. Mode 2 can only be used with data that is
tolerant of data errors, such as audio, image, and movie files.
High Sierra Format
This was a format that expanded, and was integrated into the Data Standard ISO 9660 format. It was
developed in 1985 by a collection of compact disc manufacturers during a conference at the High
Sierra Hotel and Casino. This format improved how the CD's VTOF was stored, namely how the CD
identified itself and its information encoding to the CD device, and how it stored its content, capacity
and its file organization. A notable feature that the High Sierra format added was the ability to store
both audio and data on the same CD, which was even capable of playback in not only a data device
but also an audio device.
White Book Video CD
The White Book format is what is used for Video CD's. Video CD use specific MPEG
encoding to allow up to 74 minutes of VHS quality, full motion video to be stored. They were used
with standalone Video CD players, and also can be played in any computer that has the right video
decoding software. Because only 74 minutes could be stored, this wasn't a good medium for digital
movies, but was used more for personal home video recordings.
Extended Architecture Format
CDROM XA is a the first format that allowed multiple VTOC's and storage sessions. This would
allow data to be stored, and then later more information could be stored. This format brought about
requirements in cd playback devices, which now had to be capable of reading and understanding the
multiple VTOC's. Any CD device that was not able to understand the multiple VTOC's would only be
able to understand and read the information which was stored in the first VTOC.
Orange Book I and II
CDR disks use the Orange Book format. It was first introduced by Philips and Sony in 1988. The first
format was capable of both single session which was part of Orange Book I or multisession recording,
which was added in Orange Book II. Multisession recording requires 13.5MB of storage for each
session after the first one, to work aroung the single VTOC that CD's had. Each session would require
its own lead in, program, and lead out spaces. The capacity of CD-R range from 650-520MB, and
decrease for every separate recording session.
Orange Book III
This format simply covers the special features that are needed for CD-RW, such as erasing, and writing
overtop of data. This allows for a single VTOC, and eliminates nearly all wasted space associated with
multisession recordings.
Universal Disk Format
UDF is the most common format for use in CD and DVD discs, it has no file size limitations, and
doesn't have a directory structure limitation that the ISO 9660 has. It allows for filenames upto 255
ASCII characters, or up to 127 Unicode characters. It also has improvements in handling (32K)
blocks and file overhead more effectively.
