1. Red Book Monthly

The red book defines the specification of CD-DA (digital audio), and CD-DA is called digital music disc for short. This was done by Philips and Sony at 1980, and other CDs were developed on this basis.

At first, the playing time of digital music CD can reach 60 minutes, and later it was improved and evolved into 74 minutes as the final standard.

The audio CD samples music at a frequency of 44. 1KHz, and the audio track sampling unit converts the digital signal with a value in the range of 16 bit, and converts the analog signal into digital data. The binary code from 8 to 14 can only be digitized by an EFM modulator, and then the 0 and 1 signals are converted into a pit (signal pit) on the CD.

The main function of CD-Audio is to play music in sequence, and each song is played from beginning to end. Therefore, the specifications of the little red book were very simple and complete at that time, and its main purpose was to provide a standard playing specification. All CD discs can play music on all CD stereos.

2. Yellow face

The Yellow Book defines the specification of CD-ROM (Compact Disc-Read Only Memory), which is called read-only CD for short. Philips and Sony published the Yellow Book in 1983. The Yellow Book is based on the Red Book, and the data stored on the CD can be divided into two types, one is music or graphic data with low precision, which can tolerate some byte errors, and the other is computer digital or text data with very strict precision, and no error bit data is allowed.

The book defines two different types of data structures: schema-1 and schema -2. In the header field of the CD-ROM sector, there are bytes indicating that the data in this area is mode-1 or mode -2. Mode- 1 means that the optical disk data contains error correction codes (288 bytes), and each sector stores 2048 bytes of data. For the data in mode 2, the error correction code is cancelled to save these spaces, so each sector can store 288 bytes more, totaling 2336 bytes. Therefore, mode 2 is more suitable for storing graphics, sound or audio-visual data.

Converted into computer data unit bytes, the conversion formula is as follows:

Mode-1: (650 megabytes) = 74 minutes X60 seconds x 75 sectors x2048 bytes = 68 1984000 bytes.

Mode 2: (742 megabytes) = 74 minutes X60 seconds x 75 sectors x2336 bytes = 77888000 bytes.

You can specify each data track on a CD as Mode- 1 or Mode-2, but the sectors in it can only have one format to store data. Most CDs are CDs, including programs, computer games, encyclopedias or * * * software. , using the mode-1 to store data. Other optical discs, such as Photo CD, CD-I and Video CD, are stored in Mode 2 mode.

With its powerful function and reasonable price, CD-ROM is an ideal choice for storing graphics, digital image signals and sound files. The CD-ROM drive itself has good protection and is not easily affected by scratches and dust, but it can't read and write at will like ordinary disks and hard disks. On an optical disc, data cannot be deleted and written repeatedly at will. Therefore, shortly after the success of CD laser music film, CD data film used by computer was also developed, which is called CD-ROM, and ROM stands for read-only memory. It is not complicated to convert music data into computer data, because the data are mainly stored in digital form on optical disks, and computer signals are processed in digital form (0 or 1).

The application of CD in multimedia is originally the owner of huge data, such as book data, reference system or parts manual. According to the statistics of 1992, 60% of all CD titles are mainly written data, but with the popularization of multimedia, many CDs are now being designed and applied to agriculture, books, commerce, medicine, catalogues, education, encyclopedias, entertainment, graphics, health care, history, leisure, literature, life, music and so on.

3. Green Paper

The Green Paper defines the specification of CD-I(Compact Disc Interactive), which is called interactive cd-rom for short. Among all specifications, the only standard includes hardware specifications, including CPU, operating system, memory, video and audio controller, and compression method of audio and video data.

CD-I is defined as consumer electronic products, that is, products with functions similar to televisions and tape recorders. You can directly connect to the TV and control it with the remote control. It has no floppy disk drive and hard disk drive, uses CD-ROM drive as data input device completely, and adopts real-time operating system.

4. orange book

The standard format defined by CD-Recordable is called recordable CD for short. It can be divided into three categories: CD-MO (Part I), CD-R (Part II) and CD-RW (Part III). CD-MO has lost its market demand because it can't be popularized. Therefore, CD-R and CD-RW are the most widely used storage media at present.

CD-R recordable discs:

You can write data on the CD at one time, and you can only write with the programming equipment and burning software of CD-R CD. You can write computer data or music, but the written data is not easy to change and delete, which is very safe for data preservation. The world's first CD-R film was designed by Japanese solar induction. Later, Mitsui Chemical and Mitsubishi Chemical of Japan successively invested in the development of new dyes and derived various types of CD-R dye materials. In order to improve reading and writing ability, strengthen light resistance, moisture resistance and durability, a more perfect recording medium has been created.

CD-RW rewritable disc:

Data can be written and erased repeatedly on CD-RW, which requires the use of CD-RW programming equipment and special recording software, so that the data on the CD can be changed and deleted freely, the service life can reach the range of 1000 times, and the flexibility of use is greater than that of CD-R, so CD-RW is a good choice for data with greater variability.

5. White paper

The standard format of white paper definition (VIDEO-CD) is called laser disc for short. The quality of the film is equivalent to that of S-VHS video. The sound effect can reach the sampling frequency of stereo (44. 1KHz, 16bits). It can be played dynamically in full screen for about 74 minutes. Added interactive menu function, you can choose clips at will. Video and audio can be digitized by MPEG- 1 technology, and movies can be stored on optical disks.

VIDEO-CD contains MPEG as a special full-motion video format. To play movies, you must also have a computer with MPC3 level or above, a CD-I player or a laser disc player.

At present, the VIDEO-CD on the market emphasizes the function of version 2.0, that is, it includes PBC (Play Control) function of interactive menu, and karaoke-CD includes digital music tracks, which achieves the best sound and light effect.

6. Blue Book

The standard format defined by the blue book (Enhanced-CD) is called enhanced CD for short. This CD-ROM refers to the characteristics of red books and yellow books. In order to use the technology derived from the fact that the music track can be placed behind the data track, the general CD music player cannot read the protected data track, while the computer's optical drive can read the data track and the music track. This technology is often used in computer game discs, so that three-dimensional music can smoothly cooperate with games and enjoy the fun of computer entertainment.