JPH10149631A - Disk reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reproducing device capable of shortening a time until a reproducing sound is outputted and making it difficult for sound cutting to occur according to a disk condition. SOLUTION: Digital audio data read from a disk 1 is temporarily stored in a buffer memory 35. For a specified period at the time of starting reproduction, the existence of errors in the digital audio data read from the disk 1 is determined. If the result of determination fines no errors, when the digital audio data is stored up to a first value in the buffer memory 35, reading of the digital audio data from the memory 35 is started and an audio signal is obtained. If errors are determined, when the digital audio data is stored up to a second value larger than the first value in the buffer memory 35, reading of the digital audio data from the memory 35 is started and an audio signal is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a disk reproducing apparatus.

[0002]

2. Description of the Related Art As a recording medium for digital audio signals and the like, a small optical disk called a "mini disk" is known. This optical disc includes a read-only disc and a disc capable of recording and reproducing an audio signal by a magneto-optical method. The outline of the optical disc for recording and reproduction will be described as follows.

That is, at the time of recording, an input analog audio signal has a sampling frequency of 44.1 kHz,
A / D conversion is performed on digital audio data having a quantization bit number of 16 bits. The digital audio data is sequentially divided into blocks for a predetermined period, and the data is compressed to a size of approximately 1/5 in units of the blocks. Is done. This data compression method combines DCT and a window function in consideration of human auditory characteristics, and is called MDCT. Hereinafter, the data compression block is referred to as a “sound group”.

[0004] The compressed audio data is subjected to an encoding process for error correction and a modulation process for recording, and the processed audio data is transferred to a disk by a magnetic head and a laser beam. Is recorded on a spiral track from the inner circumference to the outer circumference.

FIG. 4 shows a format of digital audio data after compression processing among signals recorded on a disk.
N, CN + 1, CN + 2,... Each cluster is composed of 36 sectors L2 to L4, S0 to S3.
The digital audio data is recorded in sectors S0 to S31. Also, sectors L2 to L
4. L1 is called a “linking sector”, and the cluster C
It is for connection with clusters CN-1 and CN + 1 following N. It should be noted that recording on the disc is performed in units of one cluster.

The size of each sector is 2352 bytes, and the audio sectors S0 to S31 are:
In each case, the first 20 bytes are used as the header and the remaining 23
32 bytes are divided into 5.5 blocks of 424 bytes each. This block is the above sound group. At this time, the even-numbered and odd-numbered sectors are regarded as one set, and the last 0.5 sound group of the even-numbered sector and the first 0.5 sound group of the odd-numbered sector constitute one sound group. You.

[0007] One sound group has a total of 512 samples of digital audio data of stereo left and right channels in a data compressed state. Therefore, the time length of one sound group is 512 samples / 44.1 kHz ≒ 11.61 ms, and the data compression rate of each channel is 424 bytes / (16 bits × 512 samples × 2 channels)
≒ 1 / 4.8 times, resulting in about 1/5 data compression as described above.

[0008] A signal having such a format is encoded for recording and then recorded as a track on an optical disk.

The above-described reproduction of the optical disk may be performed in a complementary manner to the recording. That is, the signal is optically reproduced from the track of the disk by the optical pickup,
Data-compressed digital audio data is extracted from the reproduced signal, error correction is performed, and the error-corrected digital audio data is decompressed.
/ A conversion. By doing so, the original analog audio signal can be obtained.

[0010]

In a disk player (or a recording / reproducing apparatus) using the above-mentioned optical disk, if the optical disk becomes dirty or vibrated, the signal reading from the disk fails, and as a result, In some cases, the digital audio data may be chipped and the reproduced sound may be interrupted.

Therefore, in an actual disc player, such interruption of sound is prevented as follows. That is, first, when a signal is read (reproduced) from the disk, the digital audio data included in the read, that is, the bit rate (bit speed) of the digital audio data before the data expansion is changed after the data expansion. , For example, equal to the bit rate of the digital audio data.

When reading signals from the disk, if everything is normal, the same digital audio data can be repeatedly obtained about five times in units of the rotation period of the disk. This means that audio data can be used effectively.

Further, the reproduction system of the disc player includes:
As schematically shown in FIG. 3, a ring buffer RBUF is provided. Then, the digital audio data after the error correction and before the data decompression are stored in the ring buffer RBUF,
At this time, the write address AWR is set at a predetermined speed, that is, at a normal time (at a normal time), at the bit rate of the digital audio data after data compression at the time of recording. At the corresponding speed, change in the increasing direction.

In this case, the writing is performed in sector units. Also, actually, a write pointer is prepared, and 1 from the address specified by the write pointer.
Digital audio data is written over a sector area. This also applies to reading.

At the same time as the writing, the digital audio data written in the ring buffer RBUF is read out, and at this time, the read address ARD is changed in the increasing direction. Then, the read digital audio data is decompressed,
After that, D / A conversion is performed to an analog audio signal.

This reading is performed in sector units.
Also, at this time, even if the reading is executed continuously, in the steady state, the writing of the digital audio data (the size of the hatched portion) in the ring buffer RBUF is performed so that the data amount (the size of the hatched portion) is always maintained at a specified amount. Is controlled.

Therefore, even if reading of a signal from the disk fails and digital audio data cannot be written to the ring buffer RBUF, the read address ARD
However, until the write address AWR catches up (until the hatched area disappears), there is no interruption in the reproduced sound.

The signal can be read from the disk several times before the read address ARD catches up with the write address AWR. Therefore, the retry of this read results in the writing to the ring buffer RBUF. The digital audio data to be reproduced can be made complete, so that the reproduced sound can be prevented from being interrupted.

At this time, the digital audio data included in the disk read signal has a bit rate about five times that of the digital audio data after data expansion, so that the write address AWR and the read address for the ring buffer RBUF are read. The interval between the ARDs can be kept at a predetermined value in a steady state, so that a failure of a signal from the disk can always be dealt with.

In this case, the digital audio data before data expansion is written to the ring buffer RBUF.
Since the readout processing is performed to prevent sound breakage, the ring buffer is compared with the case where the same processing is performed using digital audio data after data expansion.
The capacity of the RBUF can be reduced to about 1/5.

By the way, as described above, the ring buffer RB
When using UF to prevent interruptions in the sound, the ring buffer RBUF is empty at the start of playback, so the ring buffer RB
Until the digital audio data is written in the UF and the write address AWR becomes the predetermined address ATH,
Waiting for reading from the ring buffer RBUF, the reading is started when the digital audio data is written up to the address ATH. Hereinafter, this address ATH is referred to as a “readable address ATH”.

Therefore, at the start of reproduction, even if the reproduction key is pressed, no reproduction sound can be obtained until the write address AWR reaches the readable address ATH, so that the readable address ATH as shown in FIG. Is required to be as small as possible.

However, when the readable address ATH is reduced, the interval between the write address AWR and the read address ARD in a steady state becomes narrower, so that when reading of the signal from the disk fails, the sound is easily cut off. . The present invention is intended to solve such a problem.

As apparent from the above description, the write address AWR and the read address ARD change according to the writing or reading of the digital audio data, but the read address WRD changes at a constant speed. Indicates each address or address area by a relative address based on the read address ARD (therefore, the readable address ATH is a relative address to the read address ARD, and the size from the read address WRD (address amount or data). Amount)).

[0025]

According to the present invention, there is provided a pickup for reading data recorded on a disk from a disk, a memory for storing data read by the pickup, and a memory for reading data from the pickup. A circuit for determining an error in the read data, a memory for storing the data read by the pickup, and a controller. If the circuit for determining the error determines that there is no error, When the first value has been stored in the memory, the controller starts reading the data from the memory, and when the circuit that determines the error determines that there is an error, the data is stored in the memory. When the second value larger than the first value is accumulated, the controller stores the memo. From it is an disc reproducing apparatus adapted to initiate a reading of the data. Therefore, in the case of a disk without a read retry, a readable address is reduced and a reproduced sound is output in a short time, and in the case of a disk with a retry,
The readable address is increased, thereby preventing sound interruption.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Considering retry of reading a signal from a disc and interruption of sound, for example, during reproduction, during a period in which digital audio data is written to a ring buffer RBUF up to a readable address ATH, If the retry does not occur, it is considered that the sound interruption hardly occurs even if the readable address ATH is small, and if the retry occurs even once, the sound interruption easily occurs when the readable address ATH is small. The present invention has been made to solve the above problems based on such points.

[Configuration of Recording / Reproducing Apparatus] FIG. 1 shows an example of a mini disc recording / reproducing apparatus to which the present invention is applied.
Reference numeral 1 denotes the mini-disc.
Is a magneto-optical disk of the standard described with reference to FIG. 4 and is housed in the cartridge 1A. A pregroove is formed on the disc 1 for controlling the tracking of the light beam, and an absolute address signal is recorded in the pregroove.

Further, the disk 1 is rotated by the spindle motor 2 and its rotation is controlled by the servo control circuit 5 so that the linear velocity of the disk 1 becomes constant. A magnetic head 3 for recording is disposed on one surface of the disk 1 through a shutter opening of the cartridge 1A, and an optical pickup 4 is disposed on the other surface of the disk 1 through a shutter opening. Placed. The focus and tracking of the optical pickup 4 are controlled by a servo control circuit 5, and the head 3 and the optical pickup 4 are controlled.
Can be moved in the radial direction of the disk 1 by the feed motor 6.

A system controller 20 is provided to manage the operation of the recording / reproducing apparatus. For this reason,
The system controller 20 is constituted by a microcomputer, and has, for example, a reproduction start routine 100 shown in FIG. 2 as a part of a program for managing its operation. Although details of this routine 100 will be described later, FIG. 2 shows only parts related to the present invention for simplicity, and also shows processing executed by peripheral circuits controlled by the system controller 20. Shown together.

Further, the system controller 20 includes:
Operation keys 10 such as an eject key, a play key, a stop key, a recording key, an erase key, and a power key are connected, and a display 30 is connected.
At 0, various kinds of information on the disk 1, for example, the elapsed time of the music being reproduced, the track number of the music being reproduced, and the like are displayed.

Reference numerals 31 to 42 denote recording / reproducing circuits. The recording / reproducing circuits are controlled by the system controller 20, and recording and reproduction are executed as follows.

[Recording] At the time of recording, a stereo analog audio signal is supplied to an A / D converter 32 through an input terminal 31 and the sampling frequency is 44.1 kHz.
The A / D conversion is performed to digital audio data having a quantization bit number of 16 bits, and this digital audio data is supplied to the audio compression encoding / decoding circuit 33 and is compressed by the MDCT to a data amount of about 1/5. You.

The compressed digital audio data is temporarily written into the buffer memory 35 by the memory controller 34, and is sequentially read out at a speed approximately five times the writing speed. If the data is data encoded /
The data is supplied to the decoding circuit 36 and encoded into the data having the sector structure described above.

Then, the encoded audio data is supplied to an EFM and CIRC encoding / decoding circuit 37, where an encoding process for error detection and correction is performed, and a modulation process suitable for recording, in this example, EFM (8-14 modulation) processing is performed. In this example, the code for error detection and correction is C
The interleave changed for D's CIRC is used. The encoding / decoding circuit 37
, Linking sectors L2 to L4 and L1 are added to form audio data having the above-described cluster structure.

Then, the audio data is supplied to the head 3 through the head drive circuit 38, and a magnetic field modulated by the audio data is supplied to the disk 1. At this time, the laser beam from the optical pickup 4 is applied to the disk 1, and the magnetic head 3 and the optical pickup 4 are moved in the radial direction of the disk 1 synchronously. Thus, the irradiation of light from the optical pickup 4 and the modulation magnetic field by the magnetic head 3 cause the disc 1 to emit light.
Is recorded with audio data from the drive circuit 38 by thermomagnetic recording.

Further, at the time of this recording, the detection output of the optical pickup 4 is supplied to the address decoder 40 through the RF amplifier 39, and the absolute address signal recorded in the pre-groove of the disk 1 is extracted and decoded. The absolute address signal obtained is EFM and CI
The data is supplied to the RC encoding / decoding circuit 37, inserted into the audio data, and recorded on the disk 1.

The absolute address signal is also supplied to the system controller 20, and is used for recognizing a recording position and controlling the position. Further, the output signal of the RF amplifier 39 is supplied to the servo control circuit 5, and the servo control is performed by the pre-groove signal of the disk 1 so that the linear velocity of the disk 1 becomes constant.

[Reproduction] At the time of reproduction, the servo control circuit 5 uses the pregroove signal to rotate the disk 1 at a constant linear velocity equal to that at the time of recording in the same manner as at the time of recording.

The optical pickup 4 detects the reflected light of the laser beam irradiating the target track, and supplies the detection output to the RF amplifier 39. For example, a focus error is detected by an astigmatism method. For example, a tracking error is detected by a push-pull method. Then, these error signals are supplied to the servo control circuit 5, and the optical pickup 4 is controlled so that the focus error and the tracking error are eliminated.

Further, in the RF amplifier 39, the difference in the polarization angle of the reflected light from the target track is detected, and a reproduced signal is taken out. The reproduced signal is binarized and the EFM and CIRC encoding / decoding circuit 3
7 is supplied.

In the EFM and CIRC encoding / decoding circuit 37, the reproduced signal is EFM-demodulated, error-corrected, and digital audio data is taken out. The digital audio data is sent to the data encoding / decoding circuit 36. The supplied digital audio data is decoded into the original compressed digital audio data. Further, the decoded digital audio data is intermittently written to the buffer memory 35 through the memory controller 34, and is sequentially read at a speed of about 1/5 of the writing speed. Note that the writing and reading are performed as described with reference to FIG.

At this time, the output signal of the RF amplifier 39 is supplied to the address decoder 40, the absolute address signal from the pre-groove is extracted and decoded, and the absolute address signal is encoded by the EFM and CIRC encoding / decoding.
The optical pickup 4 is supplied to the system controller 20 through the decode circuit 37 and
Is used to control the reproduction position in the radial direction of the disc. In the system controller 20, address information in sector units is also extracted from the reproduction signal, and is used for managing the reproduction position of the optical pickup 4.

Thus, the digital audio data whose data has been expanded is continuously read from the buffer memory 35. Then, the read digital audio data is supplied to the audio compression encoding / decoding circuit 33 through the memory controller 34 and expanded to original digital audio data, and the digital audio data is supplied to the D / A converter 41. Then, the digital signal is D / A converted into the original stereo analog signal, and the stereo analog signal is taken out to the output terminal 42.

[Start of playback] In addition to the above-described playback operation,
Particularly, in the present invention, the following processing or operation is executed at the start of reproduction.

That is, the buffer memory 35 is configured as a ring buffer RBUF as shown in FIG. 3 by address processing of the memory controller 34, and writes and reads digital audio data in a normal state (normal state). Is executed as described above.

Further, in the ring buffer RBUF, two readable addresses ALO and AHI are prepared as readable addresses ATH. In this case, the readable address ALO is a value that shortens the time from the start of reproduction to the time when the reproduced sound is actually output, that is, a value that makes the interval with the read address ARD relatively narrow. Also, the readable address AHI is a value that allows a sufficient retry when a signal from the disk fails, that is, a value at which the interval from the read address ARD is relatively wide.

When the reproduction key of the operation keys 10 is pressed in the stop mode, this is detected by the system controller 20 and the reading of the signal from the disk 1 is started. Also, the system controller 20
, The processing of the routine 100 starts from step 101, and then in step 102, the address A of the memory controller 34 to the ring buffer RBUF
WR and ARD are set to initial values.

Subsequently, in step 103, for example, the audio compression encoding / decoding circuit 33 is controlled so that the encoding / decoding circuit 33
Is supplied with null data, so that this step 10
From the point of time 3, no signal is output to the terminal 42. That is, muting is turned on. Then, in step 104, the readable address A
TH is set to the first readable address ALO.

Next, at step 111, the write address AWR for the ring buffer RBUF of the memory controller 34 is incremented to the next address. At step 112, the write address AWR at this time is incremented.
Is checked to be equal to the readable address ATH. In the present case, the ATH
= ALO, it is checked whether the write address AWR has reached the readable address ALO.

As a result of this check, when the write address AWR is not equal to the readable address ATH, that is, in this case, when the write address AWR has not reached the readable address ALO, the processing proceeds from step 112 to step 113. In step 113, the EFM and CIRC encoding / decoding circuit 37 outputs a flag C2 indicating whether there is an error in the decoded digital audio data.
PO (strictly speaking, data indicating whether or not it is determined that error correction by the C1 and C2 sequences cannot be performed) is extracted, and the flag C2PO is checked.

As a result of this check, if there is no error, the process returns to step 111. If there is an error, the process returns from step 113 to step 114.
In this step 114, the readable address ATH is set to the second readable address AHI, and then the process returns to step 111.

Further, in parallel with the above processing, digital audio data of which error has been corrected for one sector is written to the write address ARD set in step 102 or 111.

Therefore, as a result, when the reproduction key is pressed, steps 111, 112, 113 (and 114) are performed.
Are repeated, and error-corrected digital audio data is sequentially written into the ring buffer RBUF one sector at a time. However, at this time, reading of the digital audio data from the ring buffer RBUF is not yet permitted, and the step 10
3, since the muting is turned on, no analog audio signal is output.

When step 114 is not executed, when the write address AWR becomes equal to the readable address ALO, that is, when the digital audio data is written up to the readable address ALO, this is determined in step 112. It is determined, and the process proceeds from step 112 to step 121.

Then, in step 121, reading of digital audio data from the ring buffer RBUF is permitted. Next, in step 122, the digital data read from the ring buffer RBUF replaces the previous null data with audio data. The data is supplied to the compression encoding / decoding circuit 33.

Therefore, the muting is released, and the digital audio data whose data has been expanded is output from the encoding / decoding circuit 33.
The / A converter 41 outputs an analog audio signal. Then, the process proceeds to a routine 130 of a normal reproduction process, and the reproduction is continued as described above.

Then, in this case, the ring buffer RB
When digital audio data is written up to the UF readable address ALO, the analog audio signal is output, so that the audio signal can be obtained in a relatively short time after pressing the reproduction key.

Then, in the state of ATH = ALO, step 12 is executed.
1 is executed when the step 114 is not executed. This is because the digital audio data of the signal read from the disk 1 has an error while the digital audio data is stored up to the readable address ALO. No, therefore, when no retry has occurred.

As described above, when no retry occurs, the readable address ATH (= AL
Since it is considered that sound breakage is unlikely to occur even if O) is small, reproduction can be performed without any problem even when the readable address ATH is small during reproduction after step 130.

That is, at the start of the reproduction, when no retry occurs in reading the signal from the disk 1, if the digital audio data is written up to the readable address ALO of the ring buffer RBUF, the reading from the ring buffer RBUF is stopped. As a result, the analog audio signal is output and the reproduction sound can be heard in a relatively short time after the reproduction key is pressed. At this time, ATH = ALO, which is small, but is hard to cause sound interruption.

On the other hand, when step 114 is executed, the write address AWR becomes the readable address AHI
, That is, when digital audio data is written up to the readable address AHI, this is determined in step 112, and the process proceeds from step 112 to step 121. Then, as described above, steps 121 and 122 are executed, and thereafter, the process proceeds to the routine 130 of the reproduction process in a normal state, and the reproduction is continued as described above.

In this case, the ring buffer RB
When digital audio data is written up to the UF readable address AHI, the analog audio signal is output, so that the audio signal can be obtained in a relatively long time after the reproduction key is pressed.

However, when ATH = AHI, step 12 is executed.
Steps 1 and subsequent are executed when step 114 is executed. This is because the digital audio data of the signal read from the disc 1 has an error while the digital audio data is stored up to the readable address ALO. Yes, when a retry has occurred.

As described above, when a retry occurs, it is considered that the sound is likely to be interrupted unless the readable address ATH is increased. Therefore, by increasing the readable address ATH to the address AHI. At the time of reproduction after step 130, it is possible to reduce the possibility of sound interruption.

That is, at the start of the reproduction, when a retry occurs in reading the signal from the disk 1, even if the reproduction key is pressed, the output of the reproduction sound is delayed (the retry is caused by contamination or vibration of the disk 1). It is considered that if the readable address ATH is small, sound breakage is likely to occur), and since the readable address ATH is increased, sound breakup is unlikely to occur.

Thus, according to the recording / reproducing apparatus described above,
Since the readable address ATH is changed according to the presence or absence of an error at the start of playback, that is, the presence or absence of a retry, when the disk 1 is free from dirt or vibration, the playback sound is pressed in a relatively short time after pressing the playback key. You can hear Further, even when the disc 1 is dirty or vibrated, the time until the reproduced sound is obtained becomes longer, but the sound is hardly interrupted.

[Others] In the above description, the routine 100
Can be executed every time reproduction is started regardless of the reproduction start position on the disc 1. Further, even if the disc 1 is a CD, the present invention can be applied by setting the track speed higher than that at the time of recording.

Further, the muting can be executed by providing a muting circuit at a stage subsequent to the D / A converter 41. When the playback key is pressed, the timer is started. If no retry occurs in reading the signal from the disk 1 before the timer expires, the readable address ATH is set to the address ALO, and the retry occurs. Then, the readable address ATH can be set to the address AHI.

[0069]

According to the present invention, when the disc is free from dirt or vibration, the playback sound can be heard in a relatively short time after the reproduction key is pressed. Although the time until the sound is obtained becomes long, the sound is hardly interrupted.

[Brief description of the drawings]

FIG. 1 is a system diagram illustrating one embodiment of the present invention.

FIG. 2 is a flowchart illustrating one embodiment of the present invention.

FIG. 3 is a schematic diagram for explaining the present invention.

FIG. 4 is a format diagram for explaining the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... Spindle motor, 4 ... Optical pickup, 5 ... Servo control circuit, 6 ... Feed motor, 20 ...
System controller, 32A / D converter, 33 ...
Audio compression encoding / decoding circuit, 34: memory controller, 35: buffer memory, 36: data encoding / decoding circuit, 37: EFM and CIRC encoding / decoding circuit, 38: head driving circuit, 39 ...
RF amplifier, 40 address decoder, 100 playback start routine, RBUF ring buffer

Claims (2)

[Claims] A pickup for reading data recorded on the disk from a disk; a memory for storing data read by the pickup; and a circuit for determining an error in the data read by the pickup. A memory for storing data read by the pickup; and a controller, wherein when the circuit for determining an error determines that there is no error, the data is stored in the memory to a first value. Then, the controller starts reading the data from the memory, and if the circuit that determines the error determines that there is an error, the controller determines that the data is larger than the first value in the memory. When the value of 2 is accumulated, the controller starts reading the data from the memory. Disk reproducing apparatus to so that. 2. The disk reproducing apparatus according to claim 1, further comprising a D / A converter, wherein the D / A converter converts the read data into an analog signal and converts the read data into an analog signal. And a disc reproducing apparatus in which muting for the analog signal is turned off.