JP3143139B2 - Intermittent playback circuit for compressed audio data - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intermittent reproduction circuit for reproducing a recording disk record formed by intermittently recording compressed audio data.

[0002]

2. Description of the Related Art A disc record in the CD-I format performs time-division recording by compressing audio data of a large number of channels on one recording track, and a reproducing apparatus stores only audio information selected from a reproduced signal. The data is expanded and converted to audio signals.

[0003]

However, the disc record in the CD-I format is not in a format suitable for recording and reproducing two-channel audio data which has been compressed. Since recording is performed while leaving many gaps in the recording track, recording efficiency is significantly reduced.

Therefore, it is conceivable to record the compressed audio data intermittently at predetermined intervals and form one recording track while connecting the intermittent recording tracks.

However, if data is reproduced in a range different from that of recording over intermittent recording tracks, not only does data processing become complicated, but also reproduction errors tend to occur at the start and end of reproduction.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a disk for forming a continuous recording track by intermittently recording, as a recording unit, recording data obtained by adding end identification data to the end of a predetermined amount of compressed audio data. In a reproducing apparatus for reproducing records, storage means for storing reproduced data at high speed and sequentially reading stored data, data amount detecting means for detecting that the amount of stored data has become equal to or less than a predetermined amount, and the storage means Decompression means for decompressing the read data, recording end detection means for detecting end identification data from the reproduction data, and continuous reproduction scanning interrupted in response to the end detection output to enter the reproduction standby state and to detect the data amount. Reproduction means for starting reproduction from the next recording start end in accordance with the output of the means.

[0007]

According to the present invention, when a disk record rotating at a constant linear velocity is reproduced, the reproduction is started from the recording start end of the intermittent recording track when the amount of data stored in the storage means becomes less than a predetermined value. When the end of recording is detected, the reproduction is interrupted. The data stored in the storage means is sequentially read at a low speed, subjected to data expansion processing, and restored to the original audio data.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a magneto-optical disk recording and reproducing system according to an embodiment of the present invention.

FIG. 1 is a block diagram of a reproducing circuit of the reproducing apparatus of the present embodiment, FIG. 2 is a block diagram of a recording circuit of the recording apparatus of the present embodiment, and FIG. 3 is a view for explaining the principle of signal processing of the present embodiment.

In this embodiment, guide tracks are previously formed on the recording surface of a disk record in the same manner as in the prior art.
This guide track is meandered by a signal FM-modulated by the ATIP code, and is reproduced as a tracking error signal during recording or reproduction. The center frequency of the carrier of the FM signal is set to 22.08 KHz, and is used as a disk servo pilot signal during recording and reproduction. Further, the ATIP code indicates an absolute address from the recording start end to the recording end of the guide track, and is composed of information of a subcode frame number of minutes, seconds and 1/75 seconds, and is recorded on the guide track at a subcode frame period. ing. The configuration described above is a configuration known as a format of a rewritable disc record.

The signal processing principle of this embodiment will be described below with reference to FIG. In this embodiment, the audio signal of the two channels is AD-converted to 4 bits at 44.1 KHz to obtain 1 bit.
It forms audio data of 4112 bits / second. This data is 2352 per subcode frame as shown.
Become bytes. In this embodiment, this AD conversion data is calculated as 1 /
5 data compression. By this data compression, 1/1
The audio data for 5 seconds is compressed to 2352 bytes as shown. This compressed data is temporarily stored in the memory,
The data is read out in units of 2048 bytes (2K bytes) and converted into a signal in CD-ROM format. CD-
As shown in the figure, a 12-byte sync data and a 4-byte header are provided at the top of each subframe signal as shown in FIG.
Eight bytes of correction data are added, and the total is 2352 bytes. The data in the CD-ROM format is subjected to a CD-DA encoding process and converted into data of 3136 bytes per subcode frame. Note that one subcode frame is composed of 98 EFM frames, and when encoding a CD-DA,
Interleave processing is performed in units of the EFM frame. Further, in this embodiment, 350 Kbytes of compressed audio data for about 10 seconds are continuously read from the memory and converted into continuous data in CD-ROM format. This continuous data is provided with a link block of one sub-code frame and a lead-in block of two sub-code frames prior to the data of the 175 sub-code frame as shown in FIG. A block and a link block of one subcode frame are provided. Therefore, in this embodiment, 181
(= 3 + 175 + 3) The recording data of about 2.4 seconds using the subcode frame as a recording unit is formed as an intermittent recording track, and a link block is recorded at the start and end of the intermittent recording track as start and end identification data.

Hereinafter, the magneto-optical recording operation of this embodiment will be described with reference to FIG. First, two-channel stereo sound is supplied to the A / D converter 1 as a recording signal. The A / D converter 1 converts each sample into 16 bits using a conversion clock of 44.1 KHz similar to the CD format. The A / D converted data is supplied to the data compression means 2 at the next stage, where it is subjected to compression processing to 1/5. The compressed audio data is sequentially stored in the memory 3.
The above operation is executed before the recording mode is set, and the write address in the memory 3 is updated to store the compressed audio data cyclically. The memory 3 has a storage area 3a for functionally storing compressed data and a storage area of 350K.
A read area 3b for storing compressed audio data of bytes and reading stored data at once according to a read command.
And a spare area 3c which functions when the storage amount of the compressed audio data increases due to a recording failure or the like and the storage area becomes insufficient.

The writing / reading control means 4 controls writing and reading to and from the memory 3 when setting the recording mode. The writing / reading control means 4 always updates and stores the compressed audio data while specifying the write address. The read address during the update interruption is equal to or more than a predetermined amount, that is, 35
When compressed voice data of 0 Kbytes or more is stored, the data is supplied to the memory 3 while updating the read address with the storage area as a read area, and the stored data is continuously read.

The write / read control means 4 sends a read command signal for commanding execution of intermittent recording in conjunction with the update of the read address to the track jump control means 13 and the CD-R.
The OM encoder 5, the CD-DA encoder 6, the magnetic head drive means 7, and the pickup 10 are supplied to make each means operative.

As a result, the read storage data is converted into the above-described CD-ROM format data by the CD-ROM encoder 5 to be recorded data, and then input to the CD-DA encoder 6. The signal is converted into a signal in the CD format, recording data is supplied from the recording start position to the magnetic head drive means 7, and magnetic field modulation is started from the recording start point.

The track jump control means 13
Supplies a track jump pulse to the tracking coil drive circuit 15 in order to continuously reproduce the same ATIP code at the end of the preceding intermittent recording track during the recording standby period, and maintains a recording standby state of about 7.6 seconds. However, during the generation period of the read command signal, the generation of the track jump pulse is inhibited, and the guide track is continuously scanned by the pickup, thereby enabling the formation of the intermittent recording track.

Further, during the period during which the read command signal is generated, the pickup 10 increases the intensity of the laser beam from the recording start end of the intermittent recording track and heats the guide track so that magneto-optical recording can be performed.

Further, the CD-ROM encoder 5
And the CD-DA encoder 6 need a subcode indicating an address at the time of encoding, respectively.
This sub-code is A for inputting the output of the reproduction amplifier 11
The ATIP code decoded by the TIP decoding means 12 is input to the subcode generation means 8 and formed. Therefore, the recorded subcode always matches the ATIP code.

On the other hand, a disk motor 19 for driving the disk record D at a constant linear velocity (1.3 m / sec) is driven by a motor drive means 18. Signal and the A
It is controlled by inputting a high-frequency tracking error signal obtained from the TIP decoding means 12 to the phase comparing means 17 and supplying a phase comparison output obtained to the motor driving means 18.

The output of the reproducing amplifier 11 is also supplied to a tracking error detecting means 14, and the tracking error signal is supplied to a tracking coil driving means 15 like a track jump pulse. The resulting tracking drive output is
And performs tracking and track jump by changing the optical axis of the objective lens.

When the read address is updated by a predetermined amount and all the data in the read area of the memory 3 has been read, the write / read control means 4 deactivates the read command signal. As a result, the CD-RO is synchronized with the deactivation of the read command signal.
The operations of the M encoder 5 and below are sequentially prohibited. Also, the track jump control means 13 latches the ATIP code at the end of recording captured by the ATIP decoding means 12 last, repeats the track jump at the end of recording, and enters a recording standby state. In addition, pickup 10
In response to the completion of the recording, the intensity of the laser beam is reduced to enter a reproduction state of recording standby.

When the storage of the compressed audio data in the new storage area 3b is completed, the write / read control means 4 generates a read command signal again in the manner described above, continuously reads the stored data, and outputs the next intermittent data. Make a record.

Intermittent recording, ie, recording for 7.6 seconds, recording for 2.4 seconds is repeated, and disk record recording data is recorded while connecting intermittent recording tracks along guide tracks.

The disc record recorded as described above is reproduced by the reproducing apparatus shown in FIG. When the rotation of the disk record D is driven by the disk motor 20 as in the recording apparatus, the reproducing apparatus shown in the drawing compares a high-frequency tracking error signal with the reference signal of the fixed oscillator 23 by the phase comparing means 22 and outputs the comparison output. The rotation of the disk motor 20 is controlled by a motor drive means 21 for inputting the data.

The pickup 24 amplifies the received light output to the reproducing amplifier 25 and supplies the amplified output to the tracking error detecting means 26 to form a tracking error signal.
It is supplied to the tracking drive unit 27 to perform tracking correction. Further, the ATIP decoding means 28
Track jump control means 2 by detecting ATIP code
9 and a high-frequency error signal and a phase comparing means 22.
To supply. Therefore, in the reproduction standby state, the track jump control means 29 supplies a track jump pulse to the tracking coil drive means 27 so that the same ATIP code is reproduced.

The configuration described above is common to the recording apparatus shown in FIG. 2, and in the recording / reproducing apparatus, these components can be used for both recording and reproduction.

Hereinafter, a reproducing operation unique to the reproducing apparatus will be described. First, a reproduction signal derived from the reproduction amplifier 25 in an initial state is decoded by a CD-DA decoder 30 and further input to a CD-ROM decoder 31. The CD-ROM decoder 31 decodes the input data, supplies the decoded data to the storage area 33a of the memory 33, detects the link block at the end of the recording by the built-in recording end detecting means 32, and outputs the end detection output. It is supplied to the write / read control means 34.

The write / read control means 34 supplies a write address to the memory 33 in order to store decoded data at a high speed in the storage area 33a of the memory 33 during reproduction, and also stores the stored storage area 33a. Is read out sequentially as a read area 33b, so that a read address is continuously supplied to the memory 33. The data amount detection means 35 built in the write / read control means 34 calculates the difference between the read address and the write address, and the storable storage area becomes 350 Kbytes (the data amount of the unit recording track length). As long as the above exists, the reproduction command signal is supplied to the track jump control means 29.

The track jump control means 29 prohibits the generation of a track jump pulse as long as the reproduction command signal is input. When the end detection signal is input while the reproduction command signal is inactive, A track jump pulse is generated in order to continuously reproduce the ATIP code and to set the reproduction standby state at the reproduction end. Therefore, at the start of reproduction, intermittent recording tracks of a plurality of units are continuously generated despite the generation of the end detection output.

When the storage area is less than 350 Kbytes, the recording end detection signal is output from the write / read control means 34.
, The supply of the write address to the memory 33 is interrupted.

In this state, the reproducing apparatus enters a reproduction standby state, and maintains the reproduction standby state until the data amount detecting means 35 generates a reproduction command signal.

The stored data that is continuously read out is expanded by the data expansion unit 36 and is stored in the D / A conversion unit 3.
7 and converted into a two-channel reproduced stereo audio signal.

As a result of reading the stored data from the memory 33, if the storable area exceeds 350 Kbytes, a reproduction command signal is generated so that data of one recording unit can be stored in the storage area 33a. Then, the reproduction standby is released, and the reproduction is started. The reproduction signal is decoded in the manner described above, stored in the storage area 33a of the memory 33, and again enters the reproduction standby state when the recording end detection output is generated.

Thereafter, each time the storable area becomes equal to or more than the data amount for one recording track length, the intermittent reproduction is restarted, and the decoded data is stored in the storage area 33a.

Although the present embodiment focuses on the storable area, ie, the empty area of the memory 33, this is completely equivalent to focusing on the storage amount, ie, the stored area, as in the expression of the claims. It is.

In this embodiment, the recording unit of the intermittent recording track is fixed at 181 subcode frames. However, the recording unit can be switched automatically or by setting as necessary. The above-mentioned reproducing apparatus can also intermittently reproduce the disk record recorded in this manner in accordance with the recording unit.

In this embodiment, the recording device and the reproduction device are separate devices. However, it is naturally possible to apply the present invention to a recording / reproduction device.
The reading control means and the like are naturally shared.

When the memory is shared, writing is started with less storage data than at the time of reproduction in consideration of the fact that the storage data amount increases due to a recording error at the time of recording. In consideration of the decrease, it is necessary to start reading in a state where there is more stored data than at the time of recording.

Further, in order to reduce the consumption of electricity at the start of recording, the storage of the compressed audio data is always continued with the rotation of the disk motor stopped, and the write address to the memory is stored in conjunction with the recording operation. However, if the recording is started by driving the disk motor to enable recording, and then reading is started from the stored write address or in the vicinity thereof, the sound of the recording start portion may be lost in conjunction with the recording operation. Can be recorded without. Furthermore, if there is enough memory capacity, the audio signal before the recording start timing can be recorded retroactively.

[0040]

As described above, according to the present invention, it is possible to process completed data for intermittently reproducing intermittent recording tracks for each recording unit, and the reproduction process can be performed reliably and easily. .

[Brief description of the drawings]

FIG. 1 is a block diagram of a reproducing circuit according to the present embodiment.

FIG. 2 is a recording circuit block diagram of the present embodiment.

FIG. 3 is an explanatory diagram of a signal processing principle of the present embodiment.

[Explanation of symbols]

 D disk record 33 memory 35 data amount detection means 36 data decompression means 32 recording end detection means 21 motor drive means 29 track jump control means

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 20/10 G11B 20/12 G11B 19/02

Claims (1)

(57) [Claims] 1. A recording method in which recording data obtained by adding termination identification data to the end of a predetermined amount of compressed audio data is used as a recording unit and the recording data is intermittently magneto-optically recorded along a spiral guide track to form a continuous line. In an optical reproducing apparatus for reproducing a disk record formed of a recording track having a constant speed, storage means for storing reproduced data at a high speed and sequentially reading out stored data, and the amount of the stored data is reduced to a certain amount or less. A data amount detecting means for detecting that the data has been read, an expanding means for expanding data read from the storage means, a recording end detecting means for detecting end identification data from reproduced data, and a disk for driving the disk record at a constant linear speed. Driving means and continuous reproduction scanning are interrupted in response to the end detection output to enter a reproduction standby state, and the next data amount detection means An intermittent reproduction circuit for compressed audio data, in which reproduction means for starting reproduction from the recording start end are arranged.