KR970008632B1 - Cd multi-graphic apparatus - Google Patents

Abstract

a CD-MG disk being recorded according to various graphic coding method; CD player for playing an electric signal from the CD-MG disk; CD-decoder for dividing the reproduced signal into audio signal and a graphic sub-code; a CD-G decoder for selecting a video signal according to a red-book method in a sub-code; CD-MG decoder for performing a decoding operation with a delta brightness/color-difference(DYUV), a color look-up table(CLUT), a run legnth, RGB 555 method; and a mixer for generating one video signal by adding an output of the CD-G decoder and an output of the CD-MG decoder or by switching the outputs of the CD-G decoder and the CD-MG decoder.

Description

Compact Disc Multi Graphics Device

1 is a block diagram showing a frame of a general compact disc format,

2 shows a subcode of a general compact disc format.

Figure 3A shows the general pack format of a compact disc,

3B is a table showing the modes defined by the mode and item bits,

4A shows the font format of the graphic mode.

4B is the screen format of the line graphic mode,

4C is the screen format of the TV graphics mode,

5 is the format of the light font foreground / background commands in the television graphics mode,

6 is a block diagram showing a decoder of a conventional compact disc graphic,

7A is a data format of delta luminance chrominance (DYUV),

7B is an RGB signal format after decoding the DYUV data of FIG. 7A,

7C is a color lookup table (CLUT) 8 data format.

7D is a color lookup table (CLUT) 7 data format.

7E is a data format of a color lookup table (CLUT) 4 method,

8A is an RGB555 data format.

FIG. 8B is the RGB signal format after decoding of FIG. 8A,

8C is a run length 7 data format.

8D is a run length 3 data format.

9 is a block diagram showing a compact disc multi-graphics (CD-MG) device according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to graphics (CD-G) using subcodes of compact discs, and more particularly to compact disc-multi graphics (CD-MG) which can accommodate various graphics coding schemes.

Sony and Philips invented compact discs (called CDs) as digital audio, and recorded them in the sub code area, which is the remaining space of CDs. It has evolved into compact disc graphics (CD-G), which provides musicians, musical scores or color screens on television screens. In order to understand the data format of the CD-G, a process of constructing a CD frame is shown in FIG. In FIG. 1, analog audio of left and right channels of a CD recorder is sampled at a sampling clock of 44.1 KHz, and then converted into a 16-bit digital signal by an analog / digital converter (not shown) to form a frame. That is, the frame A of the CD includes one byte (0) for control and display, PCM (PCM), voice data 12 bytes (1 to 16), error correction code 4 bytes (13 to 16), and a PC ( PCM) Voice data consists of 12 bytes (17 to 28) and error correcting codes (29 to 32) in total of 33 bytes. This one-byte data becomes 14 bits + combined bits (3 bits) = 17 channel bits by 8-14 (EFM) modulation. Therefore, one frame after EFM modulation adds up to 588 channel bits in total by synchronizing signal 24 channel bits + 3 channel bits and 33 x 17 channel bits. The period T after EFM modulation is

Becomes

2 shows how packets are formed from subcodes of CD frames. 98 frames constitute one sector from frame 1 to frame 98, and the subcodes (8 bits) are P, Q, R, It is named S, T, U, V, W. Here, the bits indicate the presence of music, the Q bits are for control, Q1 and Q2 are for synchronization, and Q6 (1) to Q98 (96) hold various information. That is, 96 bits from Q6 to Q98 are flag (4 bits), address (4 bits), track number (8 bits), index (8 bits), minute (8 bits), seconds (8 bits), subcode frame number. (8 bits), undefined (8 bits), absolute (8 bits), absolute seconds (8 bits), absolute frame number (8 bits), and CRC (16 bits). In addition, R, S, T, U, V, W (6 bits: symbol) are used for graphics, S0 and S1 are for synchronization, and 24 symbols from symbol (0) to symbol (23) are packed in one pack. Pack is formed, and four packs form one packet (96 symbols).

Figure 3A shows the pack format, where symbol 0 is a command and is divided into modes and items, symbol 1 is an instruction, symbols 2 and 3 are parity (Q0, Q1), and symbols 4 to 19 are data fields. The symbols 20 to 23 are parity P0 to P3. FIG. 3B is a table showing a mode name defined according to the command bits of FIG. 3A. '000000' represents a zero mode, '001000' represents a line graphic mode, and '001001' a TV graphic mode. Zero mode maintains the original image with no operation. Line graphic mode defines the screen to have a linear image of 50 fonts x 4 fonts, and TV graphic mode is a screen that has a mode of 50 fonts x 18 fonts. It is defined.

FIG. 4A shows a font composed of 6 pixels x 12 pixels, and FIG. 4B shows a screen of 50x4 fonts of a line graphic mode, and FIG. 4C shows a 50x18 font of a TV graphic mode. The screen is shown.

5 is a format of the Write Font Foreground / Background command of the TV graphics mode, in which an address indicating a background color, a foreground color, font data, and a font position on a screen is recorded. Here, the color can express 16 colors with 4 bits.

6 is a block diagram of a conventional CD-G apparatus according to the above-described method. The pickup is read from the compact disc 10 and reproduced as an electric signal in the CD player 12 by reading the signal recorded on the disc. The reproduced electrical signal is separated into video graphic data and audio data by the CD decoder 14, and the audio signal 100 is transmitted from the speaker of the left and right channels (not shown) to the stereo amplifier (not shown). I hear you. The video graphics signal is decoded by the CD-G decoder 16 and output as an RGB signal 101 for display on a cathode ray tube (CRT). Such a conventional CD-G has a disadvantage in that the data compression ratio is small and a natural image cannot be displayed by recording and reproducing a graphic image only by the method defined in the red book, which is a CD standard.

Accordingly, the present invention is to provide a compact disk multi-graphics device (CD-MG) that can use a variety of graphics coding schemes.

In order to achieve the above object, the present invention provides a CD-MG disc recorded according to various graphic coding schemes, a CD player for reproducing electric signals from the CD-MG disc, and the reproduction signal into audio signals and subcodes. A CD-G decoder extracting a video signal according to a red book method from a CD decoder and a red book method in the sub code, and a delta luminance / color difference (DYUV) method and color in the sub code. The output of the CD-MG decoder, the output of the CD-G decoder, and the output of the CD-MG decoder, which are decoded using a look-up table method, a run length, and a red-green 555 (Red, Green, Bule555) method. And a mixer for adding or switching the outputs to output a displayable audio signal.

7A is a data format of delta luminance / color difference (DYUV) decoding. DYUV decoding is mainly used for high-quality natural images, and delta means differential coding and uses correlation between adjacent pixels. will be. DYUV decoding primarily decodes DYUV into YUV and then decodes YUV into RGB. The difference between adjacent pixels is quantized into 4 bits by a non-uniform 16-level fixed quantizer and 16 steps (0,1,4) from 0 to 255 inversely by a dequantizer. , 9,16,27,44,79,128,177,212,229,240,247,252,255. In this case, Y means luminance and U & V means color difference. Color difference signals from 0 to 255 to 1 to 255 are converted into RGB signals by the following formula.

R = Y + 1.371 (V-128)

G = Y-0.337 (U-128) -0.698 (V-128)

B = Y + 1.733 (U-128)

The expected values of R, G, and B are 0 to 255. If it is 0 or less, it is 0. If it is 255 or more, the upper and lower limits are set. FIG. 7B shows the RGB signal after the decoding of the DYUV data of FIG. 7A is completed, and is divided into the 7th n-th RGB data and the 7-bit n + 1th RGB data. 7C to E show data formats of the CLUT method. A CLUT (Color Look Up Table) is a method of creating a table in which a color is defined in RAM and specifying a color using an address specifying a position on the table. Fig. 7C shows the CLUT8 scheme, which can specify 256 colors with an 8-bit address. Fig. 7D shows the CLUT7 scheme, and provides 7-bit standard resolution of 126 colors, and Fig. 7E shows the CLUT4 scheme. One can specify 16 colors of 4 bits. Figure 8A shows the RGB555R scheme, which is mainly used for computer graphics images, which use five bits for each of the RGB to define the color of the pixel. The most significant bit T is the transparence bit. FIG. 8B shows the decoding of the RGB of FIG. 8A into 7-bit RGB data, and processed the lowest bit 2 bits as '00'. 8C to D show the RL method, which is useful for reproduction of an image in which image data does not change frequently in the same video line. As shown in FIG. 8C, RL7 can normally determine many pixel values with less data by using two lines of data in which the color of the CLUT address (7 bits) represents the same color lines as the pixels of the RL (8 bits) value. have. RL3 is a color indicated by a 3-bit CLUT address as shown in FIG. 8D and includes as many pixels as indicated by 8-bit length. The coding data formats of various schemes shown in Figs. 7A to E8 and 8A to D can be appropriately represented on the data field (6 bits x 16 symbols = 96 bits) shown in Fig. 3A according to the coding scheme.

9 is a block diagram showing a compact disc-multi-graphics (CD-MG) device according to the present invention. In FIG. 9, the CD-MG disc 20 is a disc recorded according to various graphic coding schemes (DYUV, CLUT, RL, RGB555, etc.) as well as graphic data of a scheme defined in a red book. The CD-MG disc 20 is converted into an electrical signal by a pickup (not shown) of the CD player 21, and is then separated into an audio signal and a graphic signal of a sub code by the CD decoder 22 and output. The graphic signal of the subcode is processed in the CD-G decoder 23 by the red book method and goes to the mixer, and the other method is processed by the CD-MG decoder 30. The CD-MG decoder 30 includes a DYUV decoder 31 for decoding a DYUV scheme, a CLUT decoder 32 for a color lookup table (CLUT) scheme, an RL decoder 33 for a run length scheme, and It is composed of an RGB555 decoder 34 having direct RGB data, which is output to the mixer 25 after performing various decoding. These decoders are available as chipsets. The mixer 25 inputs the output of the CD-G decoder 23 and the output of the CD-MG decoder 30 to output one video signal for display. In addition, a method of displaying a coding method on a CD so as to distinguish which method is used when coding graphic data is a method of using a table content (TOC) of a lead-in-area (for each coding in AO PSEC). Value), a method of displaying on the Q channel of the subcode, and a method of displaying the command of the CD-G packet format as the user mode 111000.

As described above, according to the present invention, by using various coding methods in addition to the standard method defined in the red book, it is possible to express a natural image, increase the compression ratio, and enjoy a high quality screen.

Claims (2)

A compact disc-graphic reproducing apparatus for reproducing a compact disc recorded by a plurality of graphic coding / decoding methods, comprising: a compact disc (CD) player for reproducing the compact disc and outputting a reproduction signal; A compact disc (CD) decoder for separating the reproduction signal into an audio signal and a graphic subcode; A compact disc-graphic (CD-G) decoder for inputting and decoding the graphic subcodes according to the CD-G standard; A compact disc-multigraphic (CD-MG) decoder which inputs the graphic subcodes and decodes them according to a graphics coding / decoding scheme except for the CD-G standard; And a mixer for adding or switching the output of the compact disc-graphic (CD-G) decoder and the output of the compact disc-multi graphics (CD-MG) decoder to output a video signal. Multi-graphics (CD-MG) player. 2. The CD-MG decoder of claim 1, wherein the compact disc multi-graphics (CD-MG) decoder includes a delta luminance / color difference (DYUV) decoder for decoding in a delta luminance / color difference method, and a color look-up table for decoding in a color look-up table method. (CLUT) decoder, a run length (RL) decoder that decodes in the run-length method, and a red-green (RGB) decoder that decodes in the red-green method; compact disc-multi-graphic (CD-MG) playback Device.