Thursday, June 14, 2012

The main Format of CD


CD-DA (Compact Disc Digital Audio)

Red Book defines the standard of CD-DA. This standard is the basic lines of the entire CD industry. Standards of other CDS are on the basis of this standard. 

The audio CD is the disc that only contains audio signal. According to the Red Book; the audio files should be the signals with a PCM with a sample frequency of 44.1 KHZ and a sample value of 16 bit binary system. This file called WAV is a digit signal without compaction. 


CD-ROM
The Yellow Book defines the standards of data CD. Data CD had two modes: Mode 1 and Mode 2. 
(1) Mode 1 (named M1): The disc with data only, under this mode, each sector is set with EDC and ECC to ensure the accurate read of data.

(2) Mode 2 (named M2): Discs without EDC and ECC, only set with CIRC, it can only revise small amount of errors in data.

Under mode 2, user data increases from the 2048 bytes in mode 1 to 2336 bytes. This mode is suitable for the storage of audio files. 

CD-ROM/XA (Extended Architecture)

The specification of CD-ROM/XA is the expansion of the CD-ROM mode 2 defined in the Yellow Book. It is a format with the features defined in Yellow Book and CD-I, which increases the methods of audio-data interleaving to store information. 


CD-I (CD-Interactive)
Green Book defines the standard of CD-I, which is a specification for the application of multi-media that integrated with text, graphics, flash, photos. The Green Book does not only gives a description of CD-ROM format under Mode 2 but also a expansion of standard to hardware, all this offers a standard to the compatibility and Operating system for the playing of discs including CD-ROM XA in the CD-ROM drivers.

The Green Book also defines that there are two forms under CD-ROM Mode 2: Form 1 and Form 2.

Form 1 (hereinafter called F1),each sector has 2048 bytes of user data, set with EDC and ECC, which is used to store data.
Form 2 (hereinafter called F2) each sector has 2324 bytes of data, does not set with EDC or ECC, which is used to store audio and video data. 

Video CD (VCD)

White Book, sometimes referred to as CD-Bridge standard, defines an environment. In this environment, CD-ROM XA, CD-Iand Photo CD can be converted from one to another with ease. Video CD is also called VCD, which adopts the format of CD-ROM/XA; it is a disc that stores audio and video data with a full dynamic MPEG-1 format. This CD can be played on VCD player; it can also be played by computers with VCD playing functions. VCD has the 1.1 version and 2.0 version. 


Photo CD

It is CDs used to store photos and data, which fit for the standard regulated by KODAK. The White Book defines the recordablity of Photo CD

CD Extra

Blue Book offers a special design of standard format to Enhanced-CD for Multi-media computers according to the features defined in the Red Book and Yellow Book. CD-Extra is an extend disc called Laser Disc, Audio CD+, CD+ or CD Plus. It has two sessions; one session is to store music rails and the other to store data rails. Usually, the CD player will read the first session first, so the music can be played automatically, the computer shall read the data on the second session, and users can also play the music on the first session by software. This technique commonly used in computer game discs, so that stereo music can tie in with the game running smoothly and enjoy the thrill of Computer Entertainment. Nowadays, some discs with music protection, such as CDS disc published by EMI and some Japanese companies that adopt this technology

Mixed Mode CD

Mixed CD has only one session, the first rail is data rail with CD-ROM /CD-ROM XA, the other 2 to 99 rails are the CD-DA format that can be used to store music rails. The mixed mode disc can be played in CD-ROM on computers but not in CD players. 


CD-R
Orange Book is the first to give definition to CD-MO and CD-WO. CD-MO is the magneto-optical disc. CD-WO is a write-once recordable compact disc. Now, recordable CD-ROM CD-R, CD-RW with the rapid development, replaced the CD-WO, and developed a DIS13490 new standards. Orange Book also defines the disc, including photos (Photo CD) of the "hybrid" specification. 

CD-R (CD Recordable):
It can be written in data or music once, if written, the data can not be changed or deleted, so it has a much higher safety grade to the storage of data.

CD-R has the same file-base as the traditional CD that uses PC materials. CD-R has screw Grooves pressed in the disc instead of pits in the optic rail. During the burning process, the organic dye stuff in the groove will form blisters when exposed to laser, this blister is pit. Once the blister forms, it can not be recovered. So CD-R can be written once.


CD-RW (CD Rewritable):
CD-RW can be read in and erased repeatedly. The repetition can be 1000 times.

CD-RW has the same grooves as the CD-R. They have almost the same theory of recording. But the recording layer is not organic dye stuff but a kind of phase change material. At present, many CD burners can support CD-RW burning. During the erasing process; the phase change material will recover its former status. So CD-RW can be read in many times. 

Others related

There are many types of CD, expect for the types above said, there are also many types such as CD-G, CD-V, KARAOKE CD, and CD-I Ready. However, they have been take place by the new type of CD, so they are rare in use now. Here is a graphic showing the relations between them.


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