KR0132815B1 - Disc driving method of video-cd player - Google Patents

Abstract

A method for driving a video-CD disk player rotating a disk in a regular line speed is disclosed. The disk is repeatedly derived according to a normal replay which is determined by a rate of speed reduction of a slow motion, and a pause rate. A read video data of the normal replay is decoded to replay a frame image. The replayed frame image is repeatedly provided during a time determined by the rate of speed reduction of the slow motion.

Description

How to Operate Video CD Player

1A and 1B show the sector structure of a VIDEO-CD.

2 is a diagram showing the track configuration of a VIDEO-CD.

3 shows the structure of the first track of the program area of a VIDEO-CD disc.

4 is a diagram showing the configuration of the INFO.VCD file shown in FIG.

5 is a diagram showing the configuration of the ENTRIES.VCD file shown in FIG.

6 shows an interpolation method of MPEG1.

7 is a diagram showing that MPEG video and audio sectors are interleaved.

8 is a diagram showing an example of the configuration of an MPEG data area.

FIG. 9A shows a typical MPEG video sector, and FIG. 9B shows a typical MPEG audio sector.

10A and 10B illustrate an MPEG video sector and an MPEG audio sector including a system header.

11 is a block diagram showing the configuration of a general VIDEO-CD player.

12 is a flowchart showing a method of driving a VIDEO-CD disc player according to the present invention.

The present invention relates to a method of playing a video CD disc player, and more particularly, to a driving method for implementing a slow motion of playing a screen at a slower speed than a normal playback speed.

VIDEO-CD is a system that plays a full motion picture combined with audio using a compact disc format. The system uses the International Standard Organization's Moving Picture Experts Group (MPEG) standard to compress video and audio information, resulting in full screen and full motion combined with high quality audio. motion) image.

One VIDEO-CD disc may contain 74 minutes of high quality audio and video programs compressed according to the MPEG1 standard.

The VIDEO-CD format is based on the CD bridge disc format. The CD Bridge is a format modified from the CD-I format to be used in the CD-ROM XA. By using the CD bridge disc concept, a VIDEO-CD disc can be played on a CD-I, CD-ROM XA, VIDEO-CD player, or the like.

VIDEO-CD discs meet the CD Bridge specification. VIDEO-CD can record data of 650M BYTE by freely combining sound, video and computer data.

VIDEO-CD records or plays back video and audio data compressed according to MPEG standards. In addition to the motion compensation DPCM algorithm for increasing the data compression rate, the MPEG standard provides a special interpolation method for implementing random access functions that a user needs to find and provide a desired part of the storage medium at that time.

The feature of the interpolation method used in the MPEG standard is to periodically insert an independently reconstructable reference frame so that it can be recovered in any frame, and insert a reconstructible frame only by referring to the reference frame between the reference frames.

Since any part of the reference frame VIDEO-CD can be played independently, the content of the disc can be quickly searched by selectively playing it.

Due to the nature of the VIDEO-CD, the disc should be rotated at a certain speed. This is called the constant linear velocity (Constant Linear Velocity) method, the prescribed value is equal to 1.2 ~ 1.4 [m / S] for the CD player.

The high speed search operation in the CLV method is performed by moving the pickup apparatus between tracks formed concentrically on the disk to access an arbitrary point.

In slow motion, the play speed must be varied according to the reduction ratio, which results in a problem of controlling the rotation speed of the disc. However, the rotational speed of the disc must be kept constant.

Accordingly, a driving method that can vary the playback speed of the screen while maintaining the rotational speed of the disk must be devised.

An object of the present invention is to provide a method of driving a VIDEO-CD disc player which achieves slow rendering in a VIDEO-CD of CLV method.

According to an aspect of the present invention, there is provided a method of driving a VIDEO-CD disc player, the method including: repeatedly driving a disc according to a normal play and a pause ratio determined according to a slow motion reduction ratio; And decoding the read video data during normal playback, and reproducing the frame image and repeatedly outputting the reproduced frame image for a time determined according to the slow motion reduction ratio. Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1A and 1B show the sector structure of the VIDEO-CD, and FIG. 1A shows the sector structure of Form 1, and FIG. 1B shows the sector structure of Form 2. FIG. Each of the VIDEO-CD sectors is 2352BYTE, and includes SYNC information, a header HEADER, and a subheader SUB-HEADER, followed by data.

The header has a sector address expressed relative to the beginning of the track (minutes: seconds). The mode is also displayed but is 1 or 2 for a VIDEO-CD.

The subheader consists of data types (audio, video, program-related data, etc.), forms (1 or 2), trigger bits (END OF RECORD and END OF FILE), and coding information.

The sector structure of the VIDEO-CD has two forms, form 1 and form 2, similar to CD-1 and CO-ROM XA (CD-ROM Extended Architecture). Form 1 is used for accommodating computer data, and Form 2 is used for accommodating compressed audio video / pictures. As shown in FIGS. 1A and 1B, Form 1 and Form 2 are distinguished through sub-headers. Form 2 has no third EDC / ECC, so it can accommodate more data than Form 2.

2 shows the track configuration of the VEDEO-CD. The VIDEO-CD has a lead-in area 20, a program area 22, and a lead-out area 24 similarly to compact discs such as CD-DA, CD-ROM, CD-I and the like.

The lead-in area 20 and the lead-out area 24 are encoded into a CD-ROM XA data track including sectors of mode 2 form 2 having no contents. In the subcodes of all sectors of the lead-in area 20 and the lead-out area 24, the file number, channel number, submode and coding information are all defined as zero.

The program area 22 may have up to 99 tracks 201... 299 numbered from 1 to 99. Although a VIDEO-CD can have a CD-DA track, the initial track must be a special VIDEO-CD data track. At the same time, the CD-DA track must be located after the VIDEO-CD data track. Each track should be at least 4 seconds long.

Each track must have a pause (PAUSE) 300, a front margin (FRONT MARGIN; 302), an MPEG data area 303, and a rear margin (REAR MARGIN; 312). Pause 300 must be at least 150 sectors (2 seconds since 1 sector is 1/75 seconds), front margin 302 must be at least 15 sectors (typically 30 sectors), and rear margin 312 should be at least It should be at least 15 sectors (typically 45 sectors).

3 is a diagram showing the structure of the first track of the program area of a VIDEO-CD disc. The number on the left is an address indicating the start position of each file. In FIG. 3, the PVD 304 is optional and used in the CD-I, and defines the location and size of the PATH TABLE. The karaoke basic information area 306 is also optional.

The VIDEO-CD information area 310 is a place where general information of a VIDEO-CD disc is stored. It starts at address 04: 00 and includes files of INFO.VCD and ENTRIES.VCD.

The INFO.VCD file has VIDEO-CD system identification information and is a one sector size file starting at 00:40:00.

ENTRIES.VCD is a one-sector size file that contains the start address of each track and starts at 00:40:01.

4 is a diagram showing the configuration of the INFO.VCD file shown in FIG. In the subhead of the INFO.VCD file, the file number is 0, the channel number is 0, the sub mode is binary 10001001, and the coding information is defined as 0.

5 is a diagram showing the configuration of the ENTRIES.VCD file shown in FIG. In the subhead of the ENTRIES.VCD file, the file number is specified as 0, the channel number is 0, the sub mode is binary 10001001, and the coding information is defined as 0.

VIDEO-CD records and plays back video and audio data compressed according to the MPEG standard ISO 11172 (hereinafter referred to as MPEG11). One pack of the MPEG1 stream is recorded in one sector of MPEG VIDEO or AUDIO.

The MPEG1 standard consists of three parts: MPEG-system, which defines a method of multiplexing and synchronizing video and audio data, MPEG-video, which defines a compression algorithm of video data, and MPEG-audio, which defines a compression algorithm of audio data.

While MPEG-Video's screen size and frame rate are basically free, MPEG recommends 352 × 240 CIF (Common Image Format) at 30 frames per second. CIF is a progressive scan of 360 × 240, which is half of that of the digital TV's CCIR 601 format, that is, 720 × 240 interlaced scans, and generally shows an image quality of about VTR.

MPEG video compression algorithm is a motion compensation DPCM that combines motion compensation, DCT, and quantization methods. The motion compensation DPCM algorithm has recently been in the spotlight as a digital method of HDTV because of its superior compression performance and universality.

In addition to the motion compensation DPCM algorithm for increasing data compression, MPEG uses a special interpolation method to implement random access that the user then needs to find and provide the desired part of the storage medium.

6 shows an interpolation method of MPEG1. MPEG1 periodically inserts a reference frame so that it can be recovered in any frame. This reference frame is called an I picture, and the I picture is encoded by a method similar to intra coding, that is, JPEG of a still picture. P-pictures and B-pictures are located between the I picture and the next I-picture. P-pictures are frames that are predicted by using motion and interstitial information from the I-pictures. In contrast, is a picture generated by making a prediction frame by interpolation between a previous I picture or a P picture and a P picture above, and then DCT encoding the difference remaining by DPCM with the frame.

Of course, when interpolating, do not simply interpolate, but find and compensate for the movement. Also, instead of always interpolating, the method with the smallest error is applied by performing all the blocks inside, front and rear prediction, and bidirectional interpolation in 16 × 16 blocks.

This B picture has two advantages instead of the disadvantage of being lost because of its large amount of computation. First, if only P picture is connected, fast forwarding function cannot be supported, but B picture is inserted between them, so if only P picture is restored except this, fast forward is increased several times. Secondly, bi-directional interpolation is more efficient than predictive code, so that the superior compression performance can be obtained, resulting in better image quality.

In a stereo music program, the left audio channel is recorded in MPEG audio channel 0 and the right audio channel is recorded in MPEG audio channel 1.

MPEG video and MPEG audio sectors are interleaved in the same way as in MPEG video and audio system targer decoders as defined in the system part of the MPEG standard to ensure that no overflow or underflow occurs. Should be given.

7 is a diagram showing that MPEG video and audio sectors are interleaved. In the MPEG data area as shown in FIG. 2, the first MPEG video sector and the first MPEG audio sector should have an MPEG system header. The first sector in the MPEG data area must be an MPEG video sector or MPEG audio sector containing the MPEG system header.

8 is a diagram showing an example of the configuration of an MPEG data area. In FIG. 8, the sector denoted by E indicates an empty sector of the front margin, the sector denoted by Vsy represents an MPEG video sector including the MPEG system header, and the sector denoted by V does not include the MPEG system header. A sector denoted MPEG video sector, denoted by Asy denotes an MPEG audio sector including an MPEG system header, and a sector denoted by A denotes an MPEG audio sector, which does not include an MPEG system header.

One MPEG sector may have one MPEG PACK and may have an ISO_11172 end code. Each MPEG PACK has either audio or video packets.

9A shows a typical MPEG video sector, and FIG. 8B shows a typical MPEG audio sector. In FIGS. 8A and 8B, PACK START has a size of 4 bytes as a fax tart code and a value of hexadecimal 000001A.

SCR is a system clock reference code and has a size of 5 bytes. MUX RATE has a size of 3 bytes.

The pack data of the MPEG video sector has 2312 bytes. The pack data of the MPEG audio sector occupies 2292 bytes and has a zero field of 20 bytes.

As shown in FIG. 8, the first MPEG video sector and MPEG audio sector of a track should have a system header. The system header has 15 bytes, which reduces the length of the pack data.

10A and 10B illustrate an MPEG video sector and an MPEG audio sector including a system header.

11 is a block diagram showing the configuration of a VIDEO-CD player. In FIG. 11, reference numeral 110 is a VIDEO-CD disc, 112 is a pickup device, 114 is a digital signal processor (hereinafter referred to as a DSP), 116 is a CD-ROM decoder, and 118 is a microcomputer. A processor, 120 is a host processor, 122 is a video decoder, and 128 is an audio decoder.

The pickup device 112 reads out the digital information recorded in the form of a pit and outputs it as an analog signal. The DSP 114 receives an analog signal output from the pickup device 112, and reproduces and outputs digital data therefrom.

The CD-ROM decoder 116 buffers the input data into a built-in RAM (not shown), and decodes the data under the control of the host processor 120 to provide it to the host processor 120. The CD-ROM decoder 116 decodes data in sector units as shown in FIGS. 1A and 1B and outputs data in pack units as shown in FIGS. 9A and 9B.

The microprocessor 118 receives a user's operation command through a control panel (not shown), drives the disk according to the user's operation, or generates and provides data to the host processor 120.

The host processor 120 controls the CD-ROM decoder 118, the video decoder 122, the audio decoder 128, and the like according to data related to an operation command from the microprocessor 118.

The host processor 120 inspects the data input through the CD-ROM decoder 116 and, in the case of normal data, separates the video data and the audio data and outputs them to the video decoder 122 and the audio decoder 128, respectively. do. The host processor 120 receives the pack unit video data and the audio data from the CD-ROM decoder 116, and separates them into packet units and outputs them to the video decoder 122 and the audio decoder 128, respectively.

The video decoder 122 decodes data according to the MPEG1 format to form data of 8 bits each of R, G, and B. The decoded digital RGB data is converted into an analog RGB signal by the RGB digital / analog converter 124, input to the RGB encoder 126, and then converted into a composite video signal and output.

The audio decoder 128 decodes the data according to the MPEG1 format. The digital audio data output from the audio decoder 128 is converted into an analog audio signal by the audio digital / analog converter 130 and passes through the low pass filter 132 to reduce noise generated during the D / A conversion process. And then output.

The driving method of the VIDEO-CD player according to the present invention will be described in detail with the block diagram shown in FIG.

12 is a flowchart showing a method of driving a VIDEO-CD disc player according to the present invention. First, the microprocessor 118 inputs the reduction ratio of the slow motion, determines the ratio of the normal reproduction and the pose operation, and controls the drive of the disk according to the determined ratio. The reduction ratio can be input by a jog shuttle, a variable resistor for speed control, or the like. As the reduction ratio of slow motion increases, the poise operation period increases. During the poise operation, the pickup apparatus repeatedly accesses the same track (a physical track formed concentrically on the disc) but does not read data recorded on the disc (step 120).

In step 120, the data recorded on the disc is intermittently read. The read data is provided to the CD-ROM decoder 116.

The CD-ROM decoder decodes the read data during normal playback and drills the video data packet and the audio data packet to the host processor 120 (step 122).

The host processor 120 discards the audio data packet among the data packets input from the CD-ROM decoder 116 and provides only the video data packet to the video decoder 122.

By discarding the audio data packet, the audio signal is not reproduced. As a result, the audio signal is automatically muted.

As another method of muting the audio signal, a method of controlling the audio decoder 128 not to operate in the host processor 120 may be devised.

The video decoder 122 receives a video data packet provided from the host processor 12, decodes the video data packet, and reproduces the frame image data. The reproduced frame image data is stored in a frame buffer memory (not shown) inside the video decoder 122.

The frame image data stored in the frame buffer memory is repeatedly read for a time determined according to the reduction ratio of the flow motion, and the frame image based on the read frame image data is reproduced and output. The output of the VIDEO-CD is a video signal with a constant scanning speed such as NTSC, PAL, etc. Therefore, slow motion can be achieved by repeating scanning each frame of the frame sequence several times.

VIDEO-CD according to the present invention as described above The drive method of the disc player has the effect of achieving slow motion without varying the rotational speed of the disc by repeating normal play and pose operations.

Claims (2)

A method of driving a video-CD disc player for rotating a disc at a constant linear speed, the method comprising: repeatedly driving a disc according to a normal playback and a pause ratio determined according to a slow motion reduction ratio; Decodes the read video data during normal playback to play back the frame image and repeatedly outputs the reproduced frame image for a time determined according to the slow motion reduction ratio. Method of driving a video CD disc player, characterized in that. The method of claim 1, wherein the audio signal is muted by discarding the audio data read during normal playback.