JPH07210923A - Recording and reproducing device for disk-shaped medium - Google Patents

Abstract

PURPOSE:To provide the recording/reproducing device for a disk-shaped medium capable of simultaneously reproducing signals at the different positions (simultaneous reproduction for two channels) by using plural reproducing means, although the signals are recorded on the inner peripheral part and outer peripheral part of the disk-shaped medium at the different speed of the medium. CONSTITUTION:The number of rotation of the medium 17 is controlled so that the reproduction by an inside reproducing means 15 among plural reproducing means 15, 16 is made possible in accordance with the position in the radial direction on the medium of the inside reproducing means 15, by which the innermost part along the radial direction on the medium is reproduced. Thus, the high speed reproduction is attained also by the outside reproducing means 16, and subsequent outputs are adjusted by buffers 14, 111.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk-shaped medium recording / reproducing apparatus capable of simultaneously reproducing a plurality of signals from a rotating disk-shaped medium by using a plurality of reproducing means.

[0002]

2. Description of the Related Art A video signal is FM-modulated and recorded on an optical disc (generally called a CAV type disc) that rotates at a constant angular velocity, and then recorded at different positions along the radial direction on the optical disc. It is convenient that different pictures can be viewed at the same time by reproducing the reproduced signals using two pickups at the same time. However, for an optical disk device capable of doing so, for example, "Video Disk Recorder VDR-V100" can be used. Development ”(Technical magazine published by Pioneer Corporation, Pioneer Technical Report No. 6
(1992-October) Pages 33 to 42 (hereinafter, the first
The above-mentioned document) is publicly known.

On the other hand, the optical disk is divided into a plurality of zones along the radial direction, and in the tracks in each zone, a signal is recorded while the disk is rotated at a constant angular velocity, and each zone is viewed. For a method (generally called ZCAV or MCAV method) of controlling the rotational speed of the disk so that the linear velocities are almost equal in each zone, see, for example, the document “OD321 Series 12-Inch Large C”.
apacity WORM OpticalDisc Drive ”(Hitachi Review
Vol.39 (1990), No. 5, pp. 273 to 276) (hereinafter referred to as the second document) and is publicly known.
In this document, a digital signal is recorded on an optical disc.

[0004]

In the above-mentioned first document, the video signal is recorded in the radial direction from the inner peripheral portion to the outer peripheral portion by the CAV method, that is, in the state where the optical disc is rotated at a constant angular velocity. ing. Therefore, when reproducing signals at different positions along the radial direction on the disc by using a plurality of pickups at the same time, by reading the signals while rotating the disc at a predetermined angular velocity, At the same time, signal reproduction using a plurality of pickups becomes possible.

On the other hand, in the ZCAV method as described in the above-mentioned second document and the method of recording by controlling the rotational speed of the disk so that the linear velocity is constant (generally called the CLV method), Signals are recorded in the inner peripheral portion and the outer peripheral portion with different rotation speeds of the optical disc. Therefore, even if an attempt is made to simultaneously reproduce signals at different positions (inner peripheral portion and outer peripheral portion) using a plurality of pickups, it is physically impossible to make the optical disc rotation speeds at both portions different at the same time. Simultaneous reproduction using a plurality of pickups cannot be performed as it is, and there is no document disclosing a technique enabling this.

Therefore, an object of the present invention is to provide a plurality of reproducing means even though the signals are recorded in the inner peripheral portion and the outer peripheral portion of the disk-shaped medium with different rotation speeds of the medium. It is an object of the present invention to provide a disc-shaped medium recording / reproducing apparatus capable of simultaneously reproducing signals at different positions (inner peripheral portion and outer peripheral portion) by using the same.

[0007]

In order to achieve the above object, according to the present invention, there is provided a recording / reproducing apparatus for recording and reproducing a signal in different angular velocity states between the inner peripheral portion and the outer peripheral portion of a rotating disk-shaped medium. ,

The recording medium has one recording means for recording a signal on the disk-shaped medium and a plurality of reproducing means for simultaneously reproducing the recording signals at a plurality of different points on the disk-shaped medium.

Signals recorded in different angular velocity states on the inner and outer peripheral portions of the disk-shaped medium are recorded in the state in which the inner and outer peripheral portions of the disk-shaped medium have the same angular velocity.
When simultaneously reproducing the recording signals at a plurality of locations across the inner peripheral portion and the outer peripheral portion of the disk-shaped medium by the plurality of reproducing means,

Of the plurality of reproducing means, the inner reproducing means for reproducing the innermost portion along the radial direction of the disk-shaped medium is responsive to the position on the disk-shaped medium in the radial direction.
By controlling the number of revolutions of the disc-shaped medium to a number of revolutions at which the inner regenerating unit can regenerate the disc-shaped medium, the disc-shaped medium is regenerated by an outer regenerating unit that regenerates an outer portion along the radial direction of the disc-shaped medium. It was decided to have a rotation speed control means that enables reproduction from the medium.

Further, in the disc-shaped medium recording / reproducing apparatus, the buffer means provided corresponding to the reproducing means in order to take out the signal reproduced by any specific reproducing means of the plurality of reproducing means to the outside without excess or deficiency. It was decided to have.

Further, in the above-mentioned disk-shaped medium recording / reproducing apparatus, the rotation speed control means reproduces an inner reproducing means for reproducing the innermost portion of the plurality of reproducing means along the radial direction of the disk-shaped medium. At the reproducing position on the disk-shaped medium, which controls the rotation speed so that the rotation speed is at least higher than the rotation speed of the disk-shaped medium when the signal is recorded. did.

Further, in the above-mentioned disc-shaped medium recording / reproducing apparatus, the recording means comprises means for compressing and encoding a signal to be recorded so that the signal becomes a predetermined recording rate or less, and recording the signal. Each of them is composed of reproducing means capable of performing decoding corresponding to the compression encoding.

To achieve the above object, according to the present invention, in a reproducing apparatus for reproducing a signal in different angular velocity states between the inner peripheral portion and the outer peripheral portion of a rotating disk-shaped medium,
Having a plurality of reproducing means for simultaneously reproducing recording signals at a plurality of different locations of the disk-shaped medium,

Signals recorded in different angular velocity states on the inner and outer peripheral portions of the disk-shaped medium are recorded in the state in which the inner and outer peripheral portions of the disk-shaped medium have the same angular velocity.
When simultaneously reproducing the recording signals at a plurality of locations across the inner peripheral portion and the outer peripheral portion of the disk-shaped medium by the plurality of reproducing means,

Of the plurality of reproducing means, the inner reproducing means for reproducing the innermost portion along the radial direction of the disk-shaped medium is responsive to the radial position on the disk-shaped medium.
By controlling the number of revolutions of the disc-shaped medium to a number of revolutions at which the inner regenerating unit can regenerate the disc-shaped medium, the disc-shaped medium is regenerated by an outer regenerating unit that regenerates an outer portion along the radial direction of the disc-shaped medium. It was decided to have a rotation speed control means that enables reproduction from the medium.

Further, in the above-mentioned disc-shaped medium reproducing apparatus,
In order to take out the signal reproduced by an arbitrary specific reproducing means of the plurality of reproducing means to the outside without excess or deficiency, the buffer means provided corresponding to the reproducing means is provided.
Further, in the reproducing apparatus, each of the plurality of reproducing means is composed of a reproducing means capable of reproducing and then decoding the signal when the signal to be reproduced is composed of a compression-coded signal.

[0018]

According to the disk-shaped medium recording / reproducing apparatus of the present invention as described above, when the recording means records and reads out signals in different angular velocity states between the inner peripheral portion and the outer peripheral portion of the disk-shaped medium, In the same angular velocity state, it is possible to read signals at different positions of the disk-shaped medium at the same time by a plurality of reproducing means,
Playback (readout) can be performed efficiently.

Further, if the reproduced signal is taken out through the buffer, the same reproduced signal as recorded can be obtained. In addition, when the signal to be recorded and reproduced is a video signal, it can be compressed and encoded and recorded, and it can be decoded during reproduction.
It is possible to increase the signal density during recording and reproduction.

The disc-shaped medium recording / reproducing apparatus according to the present invention can be used as a reproducing apparatus except for the recording means, to achieve the same operation and the same advantages.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a disk-shaped medium recording / reproducing apparatus as an embodiment of the present invention. In the figure, 1
Reference numeral 0 is a video signal input terminal, 11 and 12 are reproduction signal output terminals, 13 is a recording signal processing circuit that compresses and encodes the input video signal and outputs it at a predetermined recording rate or less, and
Reference numeral 14 is a buffer memory for receiving and temporarily storing the signal from the compression-coded recording signal processing circuit 13.

Further, 17 is a writable optical disk,
Reference numeral 15 is a pickup for reading the signal recorded on the disk 17 (pickup for writing and reading) while writing the compression-encoded signal on the disk 17, and 16 is a signal for reading the signal recorded on the disk 17. Pickup (pickup for reading),
Reference numeral 19 is a motor for rotating the disk 17, and 18 is a control circuit for controlling the pickups 15, 16 and the motor 19.

Reference numeral 111 is a buffer memory for temporarily storing the signal read by the pickup 16 from the disk 17. Reference numerals 112 and 113 are reproduction signal processing circuits for outputting signals (compression-coded signals) from the buffer memories 14 and 111, respectively, after performing reproduction signal processing such as decompression processing. In addition, 180 is a signal input terminal for designating movement or stop of the pickup 15,
Reference numeral 182 is an input terminal for a signal indicating recording or reproduction, and 183 is an input terminal for a signal designating a reproduction rate at the time of reproduction.

Now, in FIG. 1, the video signal to be recorded inputted from the terminal 10 is inputted to the recording signal processing circuit 13. In the recording signal processing circuit 13, the video signal to be recorded is bit-compressed and encoded so as to have a predetermined recording rate or lower, and a parity code or the like for error correction is added. Further, processing such as addition of addresses, field numbers, frame numbers, time codes, rearrangement of signals, etc. is performed as necessary.

In the bit compression coding in the recording signal processing circuit 13, the amount of data that is compression-coded and output varies depending on the pattern of the video signal input to the processing circuit 13. That is, the amount of data output from the recording signal processing circuit 13 changes for each field of the input video signal.

The output signal from the recording signal processing circuit 13 is
It is input to the buffer memory 14. Buffer memory 14
The output signal read from the pickup 15
Is recorded on the disc 17 at a constant rate via the. The buffer memory 14 changes between the amount of time-varying data input from the output side of the recording signal processing circuit 13 and the amount of data recorded on the disc 17 via the pickup 15 at a constant rate. Has the role of adjusting.

A control signal supplied from the control circuit 18 to the pickup 15 controls the position at which data is recorded on the disk 17 (the writing position of the pickup 15) and the tracking control of the pickup 15. Also,
The rotation of the disk 17 is performed by the motor 19, and the number of rotations is performed by a control signal supplied from the control circuit 18 to the motor 19.

Here, it is assumed that the signal is recorded on the disk 17 according to the ZCAV method described in the above-mentioned second document. Therefore, the number of rotations of the disk 17 is different when recording on the inner peripheral portion of the disk 17 and when recording on the outer peripheral portion.

Here, the ZCAV system will be described below to the extent necessary to understand the present embodiment. ZCAV method is CA
This method eliminates the unevenness of the recording density between tracks, which is a drawback of the V method. Next, the ZCAV system will be described with reference to FIG. FIG. 2 is a plan view of a disk adopting the ZCAV system.

As shown in FIG. 2, in the disk adopting the ZCAV system, the disk surface is divided into n areas (zones) along the radial direction, and Z1, Z2, ...... Zn-1 and Zn are assigned symbols.
There is a fixed number of tracks in each zone. The angular velocity during rotation of the disk is controlled so that the linear velocity in each of the n zones is substantially constant. In other words, the angular velocity during rotation of the disk is controlled to decrease as n increases. Therefore, the difference in recording density between tracks is reduced, and the storage efficiency during recording is improved. This system has the features of the CLV system, such as a large data storage capacity, and the CAV system, which has a high access speed.

Now, returning to FIG. 1, details of recording a signal (data) compressed and encoded by the recording signal processing circuit 13 on the disk 17 will be described. When recording on the disk 17, a signal (data) is recorded by dividing it into sectors that represent a fixed data amount unit that is the minimum synchronization unit during reproduction. 1 track has m
There are (positive integer) sectors, and the value of m differs depending on the zone, and the value of m becomes larger in the outer zones.

FIG. 3 is an explanatory diagram showing the sectors which form the tracks of the video signal recording portion. In the figure, it is assumed that the track is composed of sectors 0 to m-1, and each sector has a synchronization pattern (SYNC) 1 and identification information (I
D) 2 and image data 3 are shown. The identification information (ID) 2 is address information or the like for indicating the position of the recorded data on the screen. The sector configured as above is shown in FIG.
It is recorded on the track of the disk 17 by the pickup 15.

Signal (data) recorded on the disk 17
Are read by the pickups 15 and 16. By having a plurality of pickups (15, 16), it is possible to simultaneously read signals at a plurality of locations along the radial direction on the disk 17. The signals read from the disk 17 by the pickups 15 and 16 are supplied to the reproduction signal processing circuits 112 and 113 via the buffer memories 14 and 111, respectively. Reproduction signal processing circuit 11
2 and 113, bit expansion processing corresponding to bit compression in the recording signal processing circuit 13 is performed. Output signals from the reproduction signal processing circuits 112 and 113 are output from the reproduction signal output terminals 11 and 12.

Next, in FIG. 1, a subsequent processing method of a reproduction signal when data at a plurality of positions along the radial direction on the disk 17 are simultaneously read by using a plurality of pickups will be described. In this case, the rotation speed of the disc 17 is controlled so that the pickup that reproduces the innermost portion on the disc 17 can read and reproduce at a rate equal to or higher than the average recording rate.

In FIG. 1, pickups 15 and 16
Now, a process for simultaneously reading data at two different positions on the disk 17 will be described. In FIG. 1, it is assumed that the pickup 15 reproduces the signal at the inner peripheral position as compared with the pickup 16. In this case, disk 1
The rotation speed of 7 is such that the pickup 15 can read the recording data at a data rate equal to or higher than the average recording rate.

As a result, the data reproduced by the pickup 15 is written in the buffer memory 14 so that the reproduced video signal output from the output terminal 11 becomes a signal having a predetermined field frequency.
4 outputs data to the reproduction signal processing circuit 112.

FIG. 4 shows the buffer memory 14 at this time.
FIG. 6 is a fluctuation characteristic diagram showing an example of fluctuations in the amount of data stored in the storage device. In FIG. 4, the vertical axis represents the amount of accumulated data and the horizontal axis represents time. The characteristic of FIG. 4 is that the pickup 1
This is the characteristic shown in the case where the disk 17 is rotationally controlled so that the reproduction rate of the data reproduced in 5 becomes the average recording rate in the disk 17.

In FIG. 4, after the reproduction is started (time t0),
A predetermined amount of data (K) is stored in the buffer memory 1
After being written in 4, the buffer memory 14 starts output to the reproduction signal processing circuit 112 (time t1). After that, the amount of data stored in the buffer memory 14 changes every moment, but the data output from the buffer memory 14 to the reproduction signal processing circuit 112 does not run out, and the data written from the pickup 15 to the buffer memory 15 is It does not overflow beyond the storage capacity of the buffer memory 14 (denoted as A).

The reproduced data is written in the buffer memory 111 by the pickup 16 which reproduces the signal at the outer peripheral position outside the reproduction position of the pickup 15 on the disk 17, and then output from the output terminal 12. Data is output from the buffer memory 111 to the reproduction signal processing circuit 113 so that the generated video signal has a predetermined field frequency.

At this time, since the pickup 16 reproduces the outer peripheral portion more than the pickup 15, the relative speed with the disc 17 is higher than that of the pickup 15, and therefore the reproduction rate of the data reproduced by the pickup 16 is higher. Is higher than the average recording rate. Therefore, if the reproduction is continued as it is, the data reproduced by the pickup 16 overflows from the buffer memory 111.

In such a case, the buffer memory 11
If the data is stored in 1 in excess of a predetermined amount, the movement of the pickup 16 on the disk surface is temporarily stopped, and the reproduction data is stored in the buffer memory 111 while the pickup 16 is reproducing the same portion. Stop writing to. Then, when the accumulated data amount has decreased to the predetermined amount, the movement of the pickup 16 and the writing of the reproduction data to the buffer memory 111 are restarted.

FIG. 5 shows the buffer memory 111 at this time.
FIG. 6 is a variation characteristic diagram showing an example of how the amount of data accumulated in the storage device varies. The vertical axis represents the amount of accumulated data and the horizontal axis represents time. In FIG. 5, after the reproduction is started (time t0), the data reproduced by the pickup 16 is the buffer memory 11
Written to 1. At the same time as the data is output from the buffer memory 14 (time t1), the buffer memory 111 also starts to output the data to the reproduction signal processing circuit 113.

Thereafter, since the average amount of data written to the buffer memory 111 is larger than the average amount of data read from the buffer memory 111, the amount of data stored in the buffer memory 111 is a predetermined amount (this is A). ) Is exceeded (time t2), the movement of the pickup 16 and the writing of the reproduction data to the buffer memory 111 are stopped. Even if the writing of the reproduction data to the buffer memory 111 is stopped, the output to the reproduction signal processing circuit 113 is continued, so that the data stored in the buffer memory 111 decreases. Then, when the amount of data stored in the buffer memory 111 becomes less than or equal to a predetermined amount (this is B) (time t
3) Moving the pickup 16 and writing the reproduction data to the buffer memory 111, following the stopped data,
Start (restart).

Through the above processing, the buffer memory 111
Also, it is possible to continuously output data, and thus it is possible to output a continuous video signal from the output terminal 12.

In the above description, the pickup 15
Although the case where the data rate reproduced in step 1 is equal to the recording rate has been described, when the data is reproduced at a rate higher than the recording rate, the same processing as the processing of the buffer memory 111 described using FIG. 5 is performed. Buffer memory 1
By applying the above for 4, the video signal can be continuously output from the output terminal 11.

Further, when the pickup 16 reproduces the inner peripheral portion of the pickup 15, the relationship between the buffer memories 14 and 111 and the pickups 15 and 16 is only reversed. In this case, the present invention is also applied. Can be applied.

In the embodiment shown in FIG. 1, the case where two pickups are used has been described, but it is clear that the present invention can be used even when three or more pickups are used. , The pickup that reproduces the innermost portion corresponds to the pickup 15 shown in FIG.
It is also possible to continuously output video signals at three or more different positions by associating another pickup with the pickup 16 and performing the same processing as that of the pickup 16 and the buffer memory 111.

FIG. 6 is a block diagram showing details of the control circuit 18 in FIG. In FIG. 6, reference numeral 180 denotes a signal (hereinafter referred to as a
0 is displayed), 181 is a signal indicating the position of the pickup 15 (hereinafter referred to as a2), 182 is a signal indicating recording or reproduction (hereinafter referred to as a3), and 183 is a signal designating a reproduction rate (hereinafter referred to as a2). 184 is a signal indicating the amount of data in the buffer memory 111 (hereinafter referred to as a6).
Input terminal.

Reference numeral 185 is a tracking control signal for the pickup 15 (hereinafter referred to as signal a1), 186 is a signal indicating the number of revolutions of the disk (hereinafter referred to as a5), and 187 is a signal for controlling the movement of the pickup (hereinafter referred to as a7). 188 is an output terminal of a signal (hereinafter, referred to as a8) for controlling reading and writing of data from and to the buffer memory 111.

Besides, 189 is a tracking control circuit for controlling the tracking of the pickup 15, 190 is a rotation speed control circuit for controlling the rotation speed of the disk, 191
Is a data amount comparison circuit for controlling reading / writing of data from / to the buffer memory 111 and controlling movement of the pickup 16. 192, 193, and 194 are rotation control circuits 1
Reference numeral 192 is a circuit that constitutes 90, and 192 is a rotation speed selection circuit for determining the rotation speed according to the position of the pickup.
Reference numeral 93 is a rate comparison circuit for calculating the ratio of the reproduction rate to the recording rate, and 194 is the rate comparison circuit 1 during reproduction.
This is a multiplier for multiplying the rotation speed selected by the rotation speed selection circuit 192 by the ratio of the reproduction rate to the recording rate calculated in 93.

In FIG. 6, a signal (a0) designating the movement or stop of the pickup 15 is input from the terminal 180 to the tracking circuit 189. Tracking circuit 1
At 89, a signal (a1) for controlling the tracking of the pickup 15 is generated in accordance with the signal a0, and the terminal 18
Output from 5.

Next, in the rotation speed control circuit 192, in the signal (a2) indicating the position of the pickup 15, a signal (a3) indicating recording or reproducing, and a signal (a indicating the reproducing rate).
Based on 4), the number of rotations of the disc is determined. Different rotation speeds are prepared in the rotation speed selection circuit 192 according to the radial position of the pickup (zone number, see FIG. 2), and a signal a2 indicating the position of the pickup 15 input to the input terminal 181 is provided. The number of rotations of the disk is selected by (b1).

The rate comparison circuit 193 has an input terminal 18
Signals a3 and a4 are input from 2 and 183, respectively. The rate comparison circuit 193 outputs 1 as the ratio of the reproduction rate (reproduction rate ≧ recording rate) to the recording rate during reproduction and 1 without performing calculation.
Output as. Then, the output signal (b1) from the rotation speed selection circuit 192 and the output signal (b2) from the rate comparison circuit 193 are multiplied by the multiplier 194 and output from the output terminal 186 as the disk rotation speed (a5).

The data amount comparison circuit 191 controls the reading / writing of data from / to the buffer memory 111 and the movement of the pickup 16. The processing shown in FIG. 7 is performed based on the signal (a6) indicating the amount of data in the buffer memory 111 input from the input terminal 184. Figure 7
Data amount in buffer memory 111 and pickup 16
And FIG.

The processing of the data amount comparison circuit 191 in FIG. 6 will be described with reference to FIG. In FIG. 7, D111
Is the amount of data in the buffer memory 111, A is the memory capacity of the buffer memory 111, and B is a predetermined amount in the relationship of 0 <B <A.

When the writing to the buffer memory 111 is started, the data amount D111 in the buffer memory 111 is 0 ≦.
In the case of the relationship of D111 ≦ B, only the writing is performed and the reading is not performed, and the pickup 16 continues to move. B <
In the case of the relationship of D111 ≦ A, both writing and reading are performed, and the pickup 16 continues to move. The amount of data D111 in the buffer memory 111 is the memory capacity A
Is reached, until it decreases to a predetermined amount B (A> D11
1 ≧ B), only reading is performed and the movement of the pickup 16 is stopped.

As described above, the signal (a7) for controlling the movement of the pickup 16 and the signal (a8) for controlling the reading and writing of data in the buffer memory 111 are respectively supplied to the terminal 18.
It is output from 7,188. This is the end of the description of the control circuit 18.

FIG. 8 shows the recording signal processing circuit 1 in FIG.
3 is a block diagram showing a specific example of FIG. The recording signal processing circuit 13 compresses and encodes the input video signal and outputs it so that the output signal from the recording signal processing circuit 13 is recorded on the disk 17 at a predetermined recording rate. In FIG.
Reference numeral 60 is an input terminal of a video signal to be recorded, 65 is an output terminal, 61 is an input signal processing circuit, 62 is an orthogonal transformation circuit, 6
Reference numeral 3 is a quantization circuit, and 64 is an encoding circuit.

In FIG. 8, an input signal processing circuit 61 performs, for example, an A / D conversion process for converting an input analog signal into a digital signal at a predetermined clock and a frequency band limitation with respect to a video signal input from a terminal 60. Performs filter processing, etc. The image data from the input signal processing circuit 61 is input to the orthogonal transformation circuit 62. Orthogonal transformation circuit 62
Then, orthogonal transform such as discrete cosine transform (DCT transform) is performed. An example of orthogonal transform when DCT transform is performed will be described below.

First, the input image data to the orthogonal transformation circuit 62 is composed of (n × n) dots in the horizontal direction and n lines in the vertical direction.
n) Divide into blocks of pixels. As an example, a case of one block (8 × 8) pixels will be described. DCT conversion is performed on each block. The converted DCT coefficient is F (u, v) (where u and v are integers of 0 to 7) and one block of image data is f (i, j) (where i and j are 0).
(Integer of ˜7), the conversion formula is as shown in Formula 1 below.

[0061]

[Equation 1]

The DCT coefficient F (u, v) thus obtained
Indicates a component obtained by dividing one block of input image data into spatial frequencies. The DCT coefficient F (0,0) indicates a value (DC component) proportional to the average value of 64 pixels of the input image data f (i, j), and F (u, v) has a larger u, v. As a result, a component with a high spatial frequency (AC component) is shown. The two-dimensional DCT coefficient obtained as described above is quantized by the quantization circuit 63.

Subsequently, the encoding circuit 64 performs variable length encoding. For the DC component, for example, some DC
Each T coefficient block is encoded using differential encoding. That is, the quantization D of the current image block and the previous image block D
The difference of the DC component in the CT coefficient is taken, and the difference value is subjected to variable length coding by Huffman coding, for example. The AC component is subjected to zigzag scanning in the order shown in FIG. 9, converted into a one-dimensional sequence, and run-length encoded to compress the number of consecutive zero data. And
Two-dimensional Huffman coding is performed by the number of consecutive run-length coded zero data and the number of bits of the effective coefficient, and the compression process is completed.

In the variable length coding process described above, bit compression can be performed by assigning a short code to data having a high occurrence probability and assigning a long code to data having a low occurrence probability. Due to the above-described encoding, the data amount for each block is non-uniform. However, when recording data in a storage device such as a disk, the recording rate must be set to a constant value on average in accordance with the recording format. Therefore, temporary data is stored in the buffer memory 14, and the data is read out from the memory 14 at a constant rate and controlled to match the recording format with that of the recording apparatus.

Next, FIG. 10 shows reproduction signal processing circuits 112 and 113 corresponding to the recording signal processing circuit 13 shown in FIG.
It is a block diagram which shows one specific example. In FIG.
80 is an input terminal for reproducing data from the disc 17;
Is a decoding circuit, 82 is an inverse quantization circuit, 83 is an inverse orthogonal transformation circuit, 84 is an output signal processing circuit, and 85 is an output terminal of a reproduction signal.

In FIG. 10, the compression-encoded data from the input terminal 80 is processed by the decoding circuit 81 as shown in FIG.
Huffman decoding processing corresponding to the encoding circuit 64 shown in FIG. After that, differential decoding is performed on the DC component,
For the AC component, run-length decoding is performed to rearrange the data in the zigzag scan order and obtain one block of transform coefficients. Then, the inverse quantization circuit 82 performs the inverse quantization,
The inverse orthogonal transform circuit 83 performs inverse DCT transform, respectively, and ends the decompression process. Then, the output signal processing circuit 84 performs D / A conversion processing for converting the digital signal into an analog signal and outputs the analog signal from the output terminal 85.

In the embodiment of the present invention described above, the case of the disk recorded by the ZCAV system has been described as an example.
It is obvious that the present invention can be applied to a disc recorded by the V method. Further, although the specific example of the recording signal processing circuit shown in FIG. 8 and the specific example of the reproduction signal processing circuit shown in FIG. 10 show the case where the input video signal is compressed and recorded and reproduced, the present invention compresses the signal. It is not essential to record in advance, and it is also possible to record without compression, and in that case, the present invention can be applied as it is to the embodiment shown in FIG.

[0068]

As described above, according to the present invention, the medium (disk) is rotated at different angular velocities between the inner peripheral portion and the outer peripheral portion on the disk-shaped medium (disk) surface. Thus, even when a signal is recorded on the disk-shaped medium (disk), signals at different positions on the disk-shaped medium (disk) can be reproduced simultaneously, which is advantageous.

[Brief description of drawings]

FIG. 1 is a block diagram showing a disk-shaped medium recording / reproducing apparatus as an embodiment of the present invention.

FIG. 2 is a plan view of a disk adopting a ZCAV system.

FIG. 3 is an explanatory diagram showing sectors forming a track of a video signal recording portion.

4 is a variation characteristic diagram showing an example of how the amount of data stored in a buffer memory 14 of FIG. 1 varies.

5 is a variation characteristic diagram showing an example of how the amount of data accumulated in the buffer memory 111 of FIG. 1 varies.

6 is a block diagram showing details of a control circuit 18 in FIG.

7 is a diagram illustrating the relationship between the amount of data in the buffer memory 111 and the movement of the pickup 16. FIG.

8 is a block diagram showing a specific example of a recording signal processing circuit 13 in FIG.

9 is a diagram illustrating a scan method in the encoding circuit in FIG.

10 is a reproduction signal processing circuit 112, 11 in FIG.
3 is a block diagram showing a specific example of FIG.

[Explanation of symbols]

13 ... Recording signal processing circuit, 14, 111 ... Buffer memory, 15, 16 ... Pickup circuit, 17 ... Disk,
18 ... Control circuit, 19 ... Motor, 112, 113 ... Reproduction signal processing circuit

Claims (7)

[Claims] 1. A recording / reproducing apparatus for recording and reproducing a signal in an inner peripheral portion and an outer peripheral portion of a rotating disc-shaped medium in different angular velocity states, and one recording means for recording the signal in the disc-shaped medium. And a plurality of reproducing means for simultaneously reproducing recorded signals at a plurality of different locations on the disk-shaped medium, and recording signals recorded in different angular velocity states on the inner peripheral portion and the outer peripheral portion of the disk-shaped medium. In a state in which the inner peripheral portion and the outer peripheral portion of the disk-shaped medium have the same angular velocity, the plurality of reproducing means simultaneously reproduces the recording signals at a plurality of locations across the inner peripheral portion and the outer peripheral portion of the disk-shaped medium. In doing so, of the plurality of reproducing means, the inner reproducing means for reproducing the innermost portion along the radial direction of the disk-shaped medium, in accordance with the position in the radial direction on the disk-shaped medium, Rotation speed , Reproduction from the disk-shaped medium is also possible by the outer reproduction means for reproducing the outer portion along the radial direction of the disk-shaped medium by controlling the number of revolutions that enables the reproduction by the inner reproduction means. A recording / reproducing apparatus for a disk-shaped medium, comprising: 2. The disk-shaped medium recording / reproducing apparatus according to claim 1, wherein a signal reproduced by an arbitrary specific reproducing means of the plurality of reproducing means is taken out to the outside without excess or deficiency, so that the reproducing means. A disc-shaped medium recording / reproducing apparatus having buffer means provided correspondingly. 3. The disk-shaped medium recording / reproducing apparatus according to claim 1, wherein the rotation speed control means controls the innermost portion of the plurality of reproducing means along the radial direction of the disk-shaped medium. At the reproduction position on the disk-shaped medium being reproduced, the number of rotations of the inner reproduction means for reproduction is at least higher than the number of rotations of the disk-shaped medium when the signal is recorded. A recording / reproducing apparatus comprising means for controlling the. 4. The disk-shaped medium recording / reproducing apparatus according to claim 1, wherein the recording means compresses and encodes a signal to be recorded at a predetermined recording rate or less, and records the signal. And each of the plurality of reproducing means is
A recording / reproducing apparatus for a disk-shaped medium, comprising a reproducing means capable of performing decoding corresponding to the compression encoding. 5. A reproducing apparatus for reproducing a signal in an inner peripheral portion and an outer peripheral portion of a rotating disc-shaped medium in different angular velocity states, in order to simultaneously reproduce recorded signals at a plurality of different portions of the disc-shaped medium. A plurality of reproducing means, the signal recorded in different angular velocity states of the inner and outer peripheral portions of the disc-shaped medium, in the state of taking the same angular velocity in the inner and outer peripheral portions of the disc-shaped medium When the plurality of reproducing means simultaneously reproduces the recording signals at a plurality of positions extending over the inner peripheral portion and the outer peripheral portion of the disk-shaped medium, among the plurality of reproducing means, the recording signals are distributed along the radial direction of the disk-shaped medium. Controlling the rotational speed of the disk-shaped medium to a rotational speed at which reproduction by the internal reproduction means is possible in accordance with the position of the internal reproduction means for reproducing the innermost part in the radial direction on the disk-shaped medium. To A disc-shaped medium having rotation speed control means for enabling reproduction from the disc-shaped medium by outer reproduction means for reproducing an outer portion along the radial direction of the disc-shaped medium. Media playback device. 6. The disc-shaped medium reproducing apparatus according to claim 5, wherein a signal reproduced by an arbitrary specific reproducing means of the plurality of reproducing means is taken out to the outside without excess or deficiency, so that the reproducing means is compatible. A disk-shaped medium recording / reproducing apparatus, characterized in that it has buffer means provided in (1). 7. The reproducing apparatus according to claim 5, wherein each of the plurality of reproducing means reproduces and decodes a signal to be reproduced, when the signal to be reproduced is a compression-coded signal. A reproducing device for a disk-shaped medium, which is composed of a reproducing means capable of reproducing.