JPH04368670A - Disk and disk reproducing device - Google Patents

Abstract

PURPOSE:To reproduce a compressed image while maintaining high image quality by classifying to the data group of the optimum compression degree in accordance with image contents, arranging time sequentially and controlling a disk to a speed corresponding to a compression ratio at the time of reproducing. CONSTITUTION:To a track 2 recording an image data column, the image data 2A of the optimum compression ratio X (2A), the image data 2B of the compression ratio X (2B) similarly and the image data 2C of the compression ratio X (2C) are recorded to arrange time sequentially and in order of reproducing. For example, the complex image data is classified to the low compression ratio group and the simple image data is classified to the high compression ratio group. Then, since the disk speed is controlled automatically to reproduce while allowing to correspond to the starting addresses 2a-2c of respective data stored to a disk control information area 3 and information X (2a)-X (2c) indicating the compression ratio to which respective data correspond at the time of reproducing, long time reproducing is capable while maintaining high image quality.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc recording system, and more particularly to a disc containing a mixture of digital image data of various compression ratios, and a disc reproducing apparatus for reproducing the disc.

0002

[Prior Art] Conventionally, compact discs (hereinafter referred to as CDs)
A technology called DVI (Digital Video Interactive), which records and reproduces highly compressed digitized image signals in a recording medium such as a DVI (abbreviated as ``Digital Video Interactive''), has been announced by Intel Corporation in the United States and other companies.

[0003] With this DVI, in order to record a maximum of 74 minutes of image signals on a CD, which is the same as the playback time of the CD's audio signal, the video signal (NTSC) is digitized and then approximately 1
The technology uses a technology that performs compression of /120 before recording data on a CD.

0004

[Problems to be Solved by the Invention] However, in the configuration using the conventional DVI, etc., the data compression rate is very high, so the playback quality after decoding is very poor, and it is difficult to use a normal VTR (video tape recorder). The problem was that the playback quality was significantly worse than that of the original.

[0005] Furthermore, in order to improve the poor image quality, attempts have been made to lower the compression rate of recorded data and increase the rotational speed of the disk to increase the data transfer rate. However, a problem arises in that the playback time is shortened.

[0006] An object of the present invention is to realize a disc and a playback device thereof that can perform long-time playback while maintaining playback image quality.

[0007]

[Means for Solving the Problems] In order to achieve this object, the present invention classifies image data to be compressed into data groups with an optimal degree of compression according to the content of the image, that is, a detailed pattern Data (data strings) with complex image content, such as natural images that contain many images, are classified into data groups with low compression ratios, and very simple image content, such as the entire screen with a blue sky, or animations, etc. Data with simple content (data strings) is classified into data groups with high compression rates, and these data groups with different compression rates are arranged in chronological order in playback order, and when playing each data group, the This method attempts to automatically variably control the rotational speed of the disk so that the speed corresponds to the compression ratio of the data group.

[0008]

[Operation] The present invention uses the above-described method to record only the parts with complicated image contents at a lower compression rate, and when playing back, controls the disc to a high rotational speed corresponding to the compression rate, while recording other parts. By significantly compressing images that are simple and controlling the disk rotation speed to a low speed corresponding to the high compression rate during playback, it is possible to play back images for a long time while maintaining high image quality.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the structure of a disk showing a first embodiment of the present invention. In FIG. 1, 1 is a disk, 2 is a part of a track on which a compressed image data string is recorded, 2A is image data with a compression rate of X (2a), 2a is its start address, and 2B is a compression rate. X (2b)
In the image data, 2b indicates its start address, and 2C indicates image data with a compression rate of X(2c), and 2c indicates its start address. 3 indicates the start addresses 2a, 2b, 2c of each of the data 2A, 2B, and 2C, and information X(2a),
This is a disk control information area that stores X(2c) in correspondence with each other.

FIG. 2 is a detailed diagram showing the contents of track 2 on which the compressed image data described in FIG. 1 is recorded.

FIG. 3 is a block diagram showing the configuration of a disc reproducing apparatus for reproducing the disc described in FIG. 1.

In FIG. 3, 1 is the same disk as the disk 1 shown in FIG. 1, and is rotationally driven by a motor 11. As shown in FIG. Reference numeral 12 denotes an information detection unit that detects information recorded on the disc 1, and usually includes an optical pickup, a traverse mechanism that transports the optical pickup, a servo circuit that controls the optical pickup and the traverse mechanism, and an output (electrical signal) of the optical pickup. ), and a waveform shaping circuit that converts the output signal of the amplifier into a digital signal, etc., and detects all information recorded on the disc 1 as a digital output signal 12a. Reference numeral 13 denotes a signal processing unit that processes the digital output signal 12a output from the information detection unit 12, and processes the detection data of the disc 1 to generate a compressed image data signal 13a, a disc rotation error signal 13b, and a disc control signal 13c. Outputs three types of signals. The disk control signal 13c includes information recorded in area 3 of disk 1 at the time of system startup, that is, compression rate information of each data X(2a), X(2b),
(2c), and position (address) information 2a, 2b, and 2c where the compression rate data exists, and during normal playback, address information indicating the playback position on the disc 1 is included. Reference numeral 14 denotes a clock extraction section for extracting a reproduced clock signal 14a from the digital output signal 12a outputted from the information detection section 12. The reproduced clock signal 14a is used as a clock signal for arithmetic processing by the signal processing section 13. Reference numeral 21 denotes a storage unit included in the system control unit 19, which stores compression rate information X (2a
), X(2b), X(2c) and the position (address) information 2a, 2b, 2c where the compression rate data exists and are stored. A motor control section 15 controls the rotation speed of the motor 11 to a predetermined rotation speed by comparing the rotation error signal 13b and the rotation reference signal 16a output from the rotation reference generation section 16. The rotation reference generation section 16 is controlled by a rotation reference control signal 19d output from the system control section 19 based on information indicating the compression ratio stored in the storage section 21 at the time of system startup. Reference numeral 17 denotes a data buffer section that temporarily accumulates and stores the compressed image data signal 13a, and the buffer output signal 17a is input to the image decoding section 20, which performs predetermined decoding processing and outputs a reproduced image. Outputs 20d. 18 receives the reproduced clock signal 14a and the buffer control signal 19b output from the system control section 19, and controls the data buffer section 1.
This is a buffer control unit that generates a control signal for controlling the processing timing of step 7. The image decoding unit 20 includes a plurality of decoders 20a, 20b, 20n that correspond to various compression rates.
, that is, decoder A with a compression ratio of 1/100, 1/50
decoder B, 1/20 decoder N, and storage unit 2
The decoder selection section 20c is controlled by a decoder selection signal 19e generated by the system control section 19 based on the data indicating the compression rate stored in No. 1. Furthermore, the decoders 20a, 20b, and 20n read and decode the buffer output signal 17a of the data buffer section 17 using the reproduced clock signal 14a of the clock extraction section 14, and the output after the decoding processing is the output of the system control section 19. The decoder selection unit 20
c, and is sent to the display device as a reproduced image signal.

The operation of the above system will be explained below with reference to FIGS.
This will be explained in detail using FIG. 3. When starting the system, the system control unit 19 gives a motor drive command 19c to the motor control unit 15 to start the motor 11. As a result, the information detection unit 12 starts detecting information in the innermost circumference of the disc 1, that is, the disc control information area 3 shown in FIG. The signal processing unit 13 reads the data in the disk control information area 3 and calculates the compression ratios X(2a) and X(
2b), The data is transferred to the storage unit 21 and stored. That is, the storage unit stores information that the start address of data with compression ratio X (2a) is 2a, the start address of data with compression ratio X (2b) is 2b, and the start address of data with compression ratio X (2c) is 2c. 21.

For the sake of clarity, in the following explanation, specific numbers such as 1/100, 1/50, and 1/20 are given to the compression ratios X(2a), X(2b), and X(2c), respectively.

[0016] Continuing to play the disc sequentially, the information detecting section 1
2 is the starting point 2a of the image data 2A with a compression rate of 1/100
When the position before , that is, the position Pa in FIG. 2 is reached, the system control unit 19 detects the state from the address information included in the disk control signal 13c,
The rotation reference control signal 19d is output with reference to the compression ratio information stored in the storage unit 21 when the system is started up, and the rotation reference generation unit 16 receives the compression ratio (X(2a)=1/100).
) is generated. Then, the motor controller 15 is controlled while comparing the rotation error signal 13b and the rotation reference signal 16a, and acceleration/deceleration control is performed so that the rotation speed Na (rpm) corresponds to the transfer rate of the compression ratio. Then, when the data playback point reaches position 2a, which is the starting point of the main body of the compressed data, the system control unit 19 detects the address and moves the storage unit 21
The decoder selection signal 19e is outputted based on the information on the compression rate (X(2a)=1/100) stored in the image decoder 20c to control the decoder selection section 20c, and the various compressions forming the image decoding section 20 are controlled. decoders 20a, 20b,
A decoder compatible with the current data from among 20n,
In this case, the decoder 20 supports a compression ratio of 1/100.
Set to select a. In this case, at the data joint where the data compression rate changes, that is, at the address 2a in FIG. 2, a time delay in acceleration/deceleration due to the moment of inertia of the motor 11 and the disk 1 always causes a time axis shift in data reproduction. Therefore, the deviation is absorbed by the primary storage function of the data buffer 17 controlled by the buffer control section 18.

Thereafter, the reproduction continues, and when the reproduction position of the disc approaches the position before the starting point 2b of the image data 2B with a compression ratio of 1/50, that is, when it reaches the position Pb in FIG. Exactly the same operation as just described is performed except for the value of , and the motor 11 has a rotational speed corresponding to its compression ratio, that is, in this case, the compression ratio is 1/2 of that in the previous example, so the previous example The image decoding unit 20 outputs a reproduced image output 20d while adjusting the time axis of the reproduced data using the temporary storage function of the data buffer unit 17. do.

In other words, when reproducing data with a high compression rate, a decoder compatible with the high compression rate is selected, and the rotational speed of the disk is controlled to a low rotational speed. When playing low data,
In addition to selecting a decoder that supports that low compression rate,
By controlling the rotational speed of the disk to a high rotational speed, images can be reproduced for a long time while maintaining the image quality at a constant high quality level.

FIG. 4 is a diagram showing the structure of a disk showing a second embodiment of the present invention. In FIG. 4, numerals 1 and 2 respectively indicate the same disk as in FIG. 1 and a portion of a track of compressed and recorded image data strings.

Further, 2A, 2B, and 2C are image data with a compression rate of 1/100, image data with a compression rate of 1/50, and image data with a compression rate of 1/20, respectively, and 2a, 2b, and 2c are the respective start addresses. shows. Also, X'(2a),
'(2b) and X'(2c) are data 2A and 2, respectively.
This data is recorded as a pair of information indicating the compression ratio of B and 2C and information on the start address of the data, and is placed ahead of the start address 2a, 2b, and 2c of each data.

In this embodiment, the disc information control area 3 shown in FIG. 1 does not exist. FIG. 5 is a detailed diagram showing the contents of track 2 in which the compressed image data described in FIG. 4 is recorded.

FIG. 6 is a block diagram showing the configuration of a playback device for controlling playback of the disc described in FIG. 4.

In FIG. 6, 1 is the same disk as the disk 1 shown in FIG. 4, and is rotationally driven by a motor 11. As shown in FIG. Reference numeral 12 denotes an information detection section that detects information recorded on the disk 1, which usually includes an optical pickup, a traverse mechanism that transports the optical pickup, a servo circuit that controls the optical pickup and the traverse mechanism, and an output (electrical signal) of the optical pickup. It is comprised of an amplifier that amplifies the signal, a waveform shaping circuit that converts the output signal of the optical pickup into a digital signal, and the like, and detects all information recorded on the disc as a digital output signal 12a. 13 is a signal processing unit that processes the digital output signal 12a output from the information detection unit 12, and processes the detection data of the disc 1 to generate an image compressed data signal 13a, a disc rotation error signal 13b, and a compressed data signal. Three types of signals are output: a disc control signal 13d including information indicating the compression rate of the disc 13a and address information indicating the disc playback position. 1
Reference numeral 4 designates a clock extraction section for extracting a reproduced clock signal 14a from the data 12a outputted from the information detection section 12. The reproduced clock signal 14a is used as a clock signal for arithmetic processing by the signal processing section 13. A motor control section 15 controls the rotation speed of the motor 11 to a predetermined rotation speed by comparing the rotation error signal 13b and the rotation reference signal 16a output from the rotation reference generation section 16. The rotation reference generation section 16 is controlled by a rotation reference control signal 19g outputted by the system control section 19 based on information indicating the compression ratio included in the disk control signal 13d. Reference numeral 17 denotes a data buffer section for temporarily accumulating and storing the compressed image data signal 13a, and the buffer output signal 1
7a is input to the image decoding section 20, and the image decoding section 20 performs a predetermined decoding process to output a reproduced image 20d.
Output. A buffer control section 18 receives the reproduced clock signal 14a and the buffer control signal 19b output from the system control section 19 and generates a control signal for controlling the processing timing of the data buffer section 17. The image decoding unit 20 includes a plurality of decoders 2 corresponding to various compression rates.
0a, 20b, 20n, that is, a decoder A with a compression ratio of 1/100, a decoder 2B with a compression ratio of 1/50, a decoder N with a compression rate of 1/20, and a decoder generated by the system control unit 19 at a predetermined timing in response to the disk control signal 13d. It is composed of a decoder selection section 20c controlled by a control signal 19d. In addition, decoders 20a, 20b, 20
n is the buffer output signal 17a of the data buffer section 17 by the reproduced clock signal 14a of the clock extraction section 14.
The output after the decoding process is read out at a predetermined speed by the readout clock signal 19a output from the system control unit 19, and then sent to the display device as a reproduced image signal via the decoder selection unit 20c. It will be done.

The operation of the above system will be explained below with reference to FIGS.
This will be explained in detail using FIG. 6. When starting the system, the system control unit 19 gives a motor drive command 19c to the motor control unit 15 to start the motor 11. As a result, the information detection unit 12 starts detecting information on the disc 1, that is, starts playing it. At this time, the discs continue to be played back sequentially, and the information detection unit 12 detects the image data 2A with a compression ratio of 1/100.
When the system controller 19 reaches the position Pa (FIG. 5) before the starting point 2a, the system control unit 19 detects the state from the disk control signal 13d and displays the information ) and the following data 2A
Detects information indicating the compression rate and its start address information. Then, based on the detected information, the system control unit 1
9 outputs a rotation reference control signal 19g to cause the rotation reference generation section 16 to generate a rotation speed reference signal 16a corresponding to the compression ratio, and outputs the rotation reference signal 16a and rotation error signal 13b.
The motor control unit 15 is controlled while comparing the rotation speed Na(r
The motor 11 is controlled to accelerate or decelerate so that When the data playback point reaches position 2a, which is the starting point of the main body of the compressed data, the system control unit 19
Referring to the data start address information detected earlier from the disk control signal 13d, the decoder control signal 19 is
A decoder that generates f and corresponds to the current data from among the decoders 20a, 20b, and 20n corresponding to various compression ratios that constitute the image decoding unit 20, in this case,
A decoder 20a that supports a compression ratio of 1/100 is selected. In this case as well, at the data joint where the data compression ratio changes, a time axis shift will always occur due to the time delay in acceleration/deceleration due to the moment of inertia of the motor 11, so this shift is controlled by the buffer control unit 18. The data is absorbed by the primary storage function of the data buffer section 17.

[0025] Thereafter, the playback continues, and when the playback position of the disc reaches the position before the starting point 2b of the image data 2B with a compression rate of 1/50, that is, the position Pb in Fig. 5, the value of the compression rate is removed. Exactly the same operation as just described is performed, and the motor 11 rotates at a rotation speed corresponding to its compression ratio, that is, in this case, the compression ratio is 1/2 of that in the previous example, so The image decoder 20 outputs a reproduced image output 20d while adjusting the time axis of the reproduced data using the temporary storage function of the data buffer unit 17.

In other words, when reproducing data with a high compression rate, a decoder compatible with the high compression rate is selected, and the rotational speed of the disk is controlled to a low rotational speed. When playing low data,
In addition to selecting a decoder that supports that low compression rate,
By controlling the rotational speed of the disk to a high rotational speed, images can be reproduced for a long time while maintaining the image quality at a constant high quality level.

[0027]

Effects of the Invention As described above, the present invention classifies image data to be compressed into data groups with the optimum degree of compression according to the content of the image. Data groups, and data with very simple image content on the screen as a whole, are classified into data groups with high compression rates, and the various data groups with different compression rates are arranged in chronological order of playback. By automatically controlling the rotational speed of the disc so that the speed corresponds to the compression ratio during playback, high-quality images that could previously only be recorded for a short time can be recorded for a long time while maintaining the same image quality. It will be possible to play it.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing a disk in a first embodiment of the present invention.

[Figure 2] Schematic diagram for explaining the information content recorded on the tracks in the disc in Figure 1

FIG. 3 is a block diagram showing the configuration of a disc playback device that plays back the disc of the first embodiment.

FIG. 4 is a conceptual diagram showing a disk in a second embodiment of the present invention.

[Fig. 5] Schematic diagram for explaining the information content recorded on the tracks in the disc shown in Fig. 4.

FIG. 6 is a block diagram showing the configuration of a disc playback device that plays back a disc according to the second embodiment.

[Explanation of symbols]

1 Disk 2 Tracks 2A, 2B, 2 on which image data strings are recorded
C Start address of data string 2a, 2b, 2c Start address of each data string 3 Disk control information area 11 Motor 12 Information detection section 13 Signal processing section 14 Clock extraction section 15 Motor control section 16 Rotation reference generation section 17 Data buffer section 18 Buffer control unit 19 System control unit 20 Image decoding units 20a, 20b, 20n Decoder 20c Decoder selection unit 21 Storage unit

Claims (3)

[Claims] Claim 1: A disc on which a plurality of data groups having different compression ratios are mixed and arranged in chronological order and recorded, the area is divided into a plurality of areas, and each of the data groups is recorded in at least one of the areas. A disc characterized in that information indicating a compression ratio and position information corresponding to the disc is recorded. [Claim 2] A disc that records a plurality of data groups, each having a different compression rate, arranged in a chronological order, in which each data group has a plurality of data groups, each having a different compression rate. 1. A disc characterized in that information indicating the compression rate of one or more preceding data groups and its position information are embedded and recorded. 3. When reproducing each data group from the disk according to claim 1 or 2, the disk is rotated based on information indicating the compression rate so that the rotation speed corresponds to the compression rate of each data group. A disc playback device characterized by controlling.