JPH087943B2 - Disc playback device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc reproducing apparatus for fast-forwarding and reproducing a disc on which compressed audio data and image data are discretely recorded.

2. Description of the Related Art In recent years, compact discs (hereinafter abbreviated as CD)
Has become widespread, and compact disc read only memory (hereinafter abbreviated as CD-ROM) is also becoming popular as a new development of CD. CD has a sampling frequency of 44.1 KHz,
This is for recording stereo 1-channel audio (hereinafter abbreviated as CD-DA data) converted into a digital signal with 16 quantization bits. CD-ROM is an image instead of this CD-DA data. Data and computer programs,
Structure and record audio data.

Hereinafter, an example of a conventional disc reproducing apparatus will be described with reference to the drawings.

First, the data formats of the CD and the CD-ROM will be described with reference to FIGS. 6 and 7.

FIG. 6 shows a format of data recorded on a CD, (a) is a schematic diagram of a data frame which is a minimum unit of recording, (b) is a schematic diagram of a subcode frame,
(C) is a schematic diagram of the Q channel data format in the program area. FIG. 7 shows the format of the data recorded on the CD-ROM. (A) is the CD-ROM
Schematic diagram of the data format of the audio block recorded in Mode 2 of FIG. 4, (b) is a schematic diagram of the sub-header of Mode 2 of the CD-ROM, (c) shows the arrangement of the audio blocks recorded in the CD-ROM It is a schematic diagram.

The CD has a lead-in area, a program area, and a lead-out area indicating the end of the disk from the inner circumference to the outer circumference of the disk, and the actual data is recorded in the program area.

A sub-channel 2 and a main channel 1 exist in one data frame and are recorded on a CD in a time division manner. The sub-channel 2 has a 1-byte data recording area, and the main channel 1 has a 24-byte data 3 recording area and an 8-byte error detection / correction code 4 recording data area of 32 bytes in total.

On a CD, CD-DA data is recorded at the position of data 3. C
This data frame is recorded in D at a rate of 7350 data frames / sec. The error detection / correction code 4 is a code for detecting and correcting a data error in the data of the main channel 1.

Before recording these data on CD, EFM (Eight-t
o-Fourteen-Modulation: Eight-to-four-modulation) modulation and data frame sync signal addition work for identifying data frame boundaries are performed. As a result, one data frame becomes 588 bits, and the bit rate when recorded on a CD is 588 × 7350 = 4.3.
It will be 218 Mbit / sec. This data is recorded in the form of NRZi signal at a constant speed (about 1.25 m / sec) in a spiral form from the inner circumference to the outer circumference.

A subcode frame is formed by subchannel 2 for 98 consecutive data frames. Subcode frame is 1
There are 75 per second. This state is shown in FIG. 6 (b).
The sub-channel 2 for the first two data frames constitutes the sub-code frame synchronization 7, and the sub-channel 2 for the remaining 96 data frames records data called sub-code. Each bit of 1 byte of the subcode corresponds to a channel, and these channels are called P channel, Q channel, ..., W channel.

The address is recorded in the Q channel 9 (6th
See FIG. (C)). For the address, the absolute time (AMIN, ASEC, AFRAME) that increases with the start of the program area at 0 minute 0 second 0 frame and the outer circumference, and the relative time (MIN, SEC, FRAME)
, And the track number and index exist, and each is recorded in BCD code (binary coded decimal). The frame here is a unit of time, and 75 frames correspond to 1 second. That is, the frame as a unit of time is equal to the time length of one subcode frame.

In the CD-ROM, 98 data frames worth of data corresponding to the length of one subcode frame, 98 × 24 = 2352 bytes, are structured as one block (see FIG. 7A). Each block has a 12-byte sync signal at the beginning for identifying a block delimiter, and a 4-byte header following the sync signal. The top 3 bytes of the header is called a physical block address, and the absolute address with the beginning of the program area as 0 minutes 0 seconds 0 block is recorded. This absolute address has a value equal to the absolute time (AMIN, ASEC, AFRAME) described in FIG. 6 (c). The last byte of the header indicates the mode, and the recorded contents of the remaining 2336 bytes differ depending on this value.

That is, in the CD-ROM, instead of the CD-DA data, the sync signal, header, sub-header, user data and the like shown in FIG. 7A are recorded.

FIG. 7A shows the data format of the audio block in mode 2. In mode 2, the header is followed by 8
The byte sub-header is recorded (see FIG. 7 (b)). A file number for identifying a file is recorded in the 0th byte and the 4th byte. In the first byte and the fifth byte, a channel number for defining the same file in more detail is recorded. The sub mode is recorded in the second byte and the sixth byte. This submode byte is bit-encoded, and the type of data recorded in this block is recorded. For example, if the data recorded in this block is image data,
A code for identifying whether it is audio data or the like is recorded in the serve mode byte. A block in which image data is recorded at the position of user data will be abbreviated as an image block hereinafter. Further, a block in which audio data is recorded will be abbreviated as an audio block hereinafter. The coding information recorded in the third byte and the seventh byte differs depending on the value of the submode byte. In the coding information byte of the audio block, the audio level indicating the sound quality of the audio data, monaural / stereo distinction, etc. are recorded. In the coding information of the image block, a code for identifying the format of the image data is recorded.

The user data area of 2324 bytes of the voice block is 12
18 8-byte sound groups are recorded, and the remaining 20
0 is recorded in the byte. Each sound group consists of 16-byte sound parameters, which are the parameters of audio data used for decoding, and the actual audio data.
112 bytes of sound data is recorded.

There are three types of compression methods, level A, level B, and level C, depending on the difference in sampling frequency and the number of bits. Since each level has a distinction of monaural / stereo, there are 6 types of compressed audio formats in total. Exists. The amount of data of Level A stereo is compressed to about half that of CD audio. Level A monaural and level B stereo
The amount of data is compressed to about 1/4 compared to the sound of CD. Level B monaural and level C stereo are compressed to about 1/8 the data amount compared to CD audio. Level C monaural has about the same amount of data as CD audio.
It is compressed to 1/16. Therefore, in the case of level B stereo, four channels of stereo sound can be recorded on the CD-ROM. It is also possible to record the audio block and the image block by time-axis multiplexing. This state is shown in FIG. 7 (c). In the figure, for example, level C
If it is monaural, the data amount is compressed to about 1/16, so record audio blocks at a ratio of 1 block to 16 blocks, and record image data at the remaining 15 blocks.
It is possible to realize an electronic picture-story show that switches images while outputting audio. It is also possible to introduce the concept of channels not only for audio but also for images, and to record images of multiple channels on a CD-ROM.

Thus, when recording audio blocks and image blocks on the CD-ROM, the audio blocks belonging to the same channel are recorded in a time-division manner so that they are arranged at regular intervals. During playback, the block where both the file number and channel number match the specified value is extracted, and if this block is an audio block, the audio data is decoded and output as audio, and if it is an image block. It is converted to a video signal by the image processing circuit and output (for example, Electronics December 1986, pages 55-60).

Next, as an example of the conventional disc reproducing apparatus, the operation when the CD player performs the fast-forward reproduction will be described with reference to FIGS. 3 and 4.

Since there is no example of performing fast-forward reproduction of a CD-ROM in which the above-mentioned audio blocks and image blocks are discretely recorded, the fast-forward reproduction of a commercially available CD player will be described.

FIG. 3 is a block diagram showing the internal structure of a CD player which is a conventional disc reproducing apparatus. In FIG. 3, a spindle motor 61 rotates a CD 59 at a constant linear velocity, and a pickup 62 reads a signal recorded on the CD 59. The read signal is converted into a digital signal by the CD signal processing circuit 63 and then subjected to error detection and correction processing. Motor control circuit 98
Is a CLV (Constant
Linear Velocity: Constant linear velocity)
Servo. In this CLV servo, the reproduction clock extracted in the CD signal processing circuit 63 is 4.3218 output by the oscillator 97.
It is performed so as to match the reference clock of MHz. The pickup control circuit 66 includes a focus servo that focuses the read laser light on the CD 59, a tracking servo that causes the read laser light to follow a recording track spirally formed on the CD 59, and a traverse servo that moves the pickup 62 to the inner and outer circumferences. I do. The CD-DA data output from the CD signal processing circuit 63 is converted into an analog audio signal via the DA conversion circuit 80 and the low pass filter 81 and output. The permission means 85 determines whether or not the track jump is possible, and the reproduction speed control means 83 outputs a track jump command to the pickup control circuit 66. The reproduction method specifying means 75 specifies a reproduction method such as fast-forward reproduction on the operation unit of the CD player. The operations performed by the reproduction speed control means 83 and the permission means 85 are specifically realized by a program executed by the microprocessor 84.

FIG. 4 is a flowchart of an interrupt processing routine executed by the microprocessor 84 when the CD signal processing circuit 63 detects the sub code frame synchronization 7. The numbers in parentheses indicate the means of doing so. For example, the operation of incrementing the internal counter in step 200 is performed by the permitting means 85.

Regarding the disc reproducing apparatus configured as described above,
The operation will be described below.

First, when the CD signal processing circuit 63 detects the subcode frame synchronization 7 during reproduction of the CD 59, an interrupt signal is generated to the microprocessor 84. When the microprocessor 84 receives the interrupt signal, the permission means 85 and the reproduction speed control means 83 operate according to the flowchart of FIG. First, in step 200, the permitting means 85 increments the internal counter. Next, in step 201, the reproduction speed control means 83 determines the state of the reproduction method designating means 75. If the fast-forward reproduction switch of the reproduction method designating means 75 is not pressed now, the interrupt processing routine ends. That is, while the normal reproduction is performed, the permitting means 85 only increments the internal counter.

When this interrupt processing routine is executed after the fast-forward playback switch is pressed, the process proceeds to step 202,
At step 202, the reproduction speed control means 83 checks the value of the counter in the permission means 85 to determine whether it is equal to or more than a predetermined value. If it is larger than the predetermined value, the reproduction speed control means 83 outputs a track jump command to the pickup control circuit 66 in step 203, and then the permission means 85 executes step
At 204, the internal counter is cleared and the interrupt processing routine ends. If this predetermined value is set to 10, for example, about 10/7
A track jump command will be output every 5 seconds.

Upon receiving the track jump command, the big-up control circuit 66 controls the pickup 62 so as to jump the reproduction position in the outer peripheral direction. For example, when the pickup control circuit 66 controls the pickup 62 so as to jump one track toward the outer circumference, the pickup 62 moves the reproduction position to the adjacent track on the outer side. Since the signal is recorded from the inner circumference to the outer circumference of the CD59, the reproduction position is advanced by the above operation, and as a result, fast-forward reproduction is realized.

When the pickup 62 performs a track jump, the continuity of the reproduction data is lost and the audio output is interrupted for a moment.

Problems to be Solved by the Invention Since CD-DA data is continuously recorded on a CD, C
When fast-forwarding reproduction is performed by the D player, even when the reproduction is performed by the above-described method, the time for which the sound is interrupted by the track jump is very short. However, when the above method is directly applied to the reproducing apparatus of the disc in which the audio blocks and the image blocks are discretely recorded, there is a problem that the time for which the audio is interrupted by the track jump becomes long. That is, if the track jump is performed at a constant time interval, the silent period due to the track jump becomes long.
Further, since the image data forming one screen is distributed and recorded in a plurality of image blocks, there is a problem that a part of the image blocks forming the screen is not reproduced and the display screen is disturbed.

This problem will be described with reference to FIG. FIG. 5 is a schematic diagram showing the state of reproduction of a CD-ROM in which audio blocks and image blocks are recorded. On this CD-ROM, audio blocks and image blocks are recorded at a ratio of 1: 3. Voice data of 4/75 seconds is recorded in each voice block. A1, A2, A3, ... indicate audio blocks, V1, V2, V
3, ... Shows image blocks. In the case of normal reproduction of this disc, as shown in FIG. 5 (a), after reading the A1 block from the CD-ROM, the audio data is expanded and the audio output for 4/75 seconds is performed. By the time the expansion processing of the A1 block is completed, the next A2 block has been reproduced from the disc, and the audio is reproduced without interruption. Further, the image block is sent to the image memory, and one display screen is displayed by the image data in the plurality of image blocks. Here, consider the case where the fast-forward reproduction is performed by the same method as that of the conventional CD player. In this case, the timing of the track jump is performed according to the elapsed time from the previous track jump, so that it is performed regardless of the type of data read from the disc. Therefore, for example, as shown in FIG. 5 (c), when the image block of V5 is read out and the track jump operation is performed at time t41 and the reproduction is restarted from the block of V11, the data of the A5 block is expanded. It is a silent period until it is output. If the time during which the data cannot be read from the disk due to the track jump is Tj, the time length of one block is Ts, and the audio data is recorded in time division for every n blocks, the track jump is performed at any timing. And the silent period Tm, the relationship of Tm <(n + 1) Ts + Tj is established. For example, in the case of the mode C monaural described above, since n = 16, even if Tj = 0, a maximum silent period of about 0.2 seconds will occur.
In addition, since the image blocks from V6 to V10 are not reproduced, a screen with a part missing is displayed.

In view of the above problems, the present invention provides a disc reproducing apparatus in which sound is not interrupted when fast-forwarding and reproducing a disc in which audio blocks and image blocks are discretely recorded, and a complete image is always displayed. To aim.

Means for Solving the Problems In order to achieve the above-mentioned object, a disc reproducing apparatus of the present invention comprises a separating means for separating and outputting for each block from data output by a reading means, and an audio block output from the separating means. , A selection means for controlling the transmission to the next stage, a storage means for temporarily storing the audio block output from the selection means, a sequential reading of the audio blocks stored in the storage means, an expansion processing, and then an analog audio signal. In the case where the audio processing output means for converting to and outputting it and the reproduction method designating means instruct fast-forward reproduction, the motor is rotated at a rotation speed of m / n times (m> n) times the rotation speed for realizing the recording speed. And a selection means for controlling the selection means so as to send n blocks of audio blocks to the next stage from the m blocks of continuous audio blocks separated by the separating means. The selection control means.

With the above-described structure, the present invention rotates the disc at the speed of m / n times that at the time of the normal reproduction at the time of fast-forward reproduction, and the selection control means selects the next n audio blocks from the continuous m audio blocks. The selection means is controlled so that the audio block is sent to the storage means, the selection means discards the audio block according to the instruction of the selection control means or sends the audio block to the storage means, and the audio processing means sequentially reads the audio blocks written in the storage means and performs the expansion processing. After that, it will be converted into an analog audio signal and output.

Embodiment A disc reproducing apparatus according to an embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 5.
FIG. 1 is a block diagram showing the configuration of a disc reproducing apparatus according to an embodiment of the present invention.

In FIG. 1, a CD-ROM 60 is a disc in which the audio blocks and image blocks described in the conventional example are recorded in a time division manner. The reading means 67 is a pickup 62, a CD signal processing circuit 63, a CD
-It is composed of a ROM signal processing circuit 64 and a pickup control circuit 66. The separating means 70 is composed of a switch circuit 93 and a subheader discriminating means 69. The voice processing output means 82 is a decompression circuit
79, DA conversion circuit 80, and low-pass filter 81.
The motor control means 91 is composed of a motor control circuit 65 and an oscillator 90. Further, the sub-header discriminating means 69, the selection control means 7
4 is realized by a program executed by the microprocessor 77. The spindle motor 61 rotates the CD-ROM 60,
The pickup 62 reads the signal stored in the CD-ROM 60. The read signal is converted into a digital signal by the CD signal processing circuit 63 and then subjected to error detection and correction processing. After that, the CD-ROM signal processing circuit 64 performs processing such as detection of a sync signal in the CD-ROM format. The motor control circuit 65 performs CLV servo that controls the rotation of the spindle motor 61.
The CLV servo is performed so that the reproduction clock extracted in the CD signal processing circuit 63 matches the reference clock output by the oscillator 90. The pickup control circuit 66 is a CD-ROM 60
A focus servo for focusing the read laser light on, a tracking servo for making the read laser light follow a recording track spirally formed on the CD-ROM 60, and a traverse servo for moving the pickup 62 to the inner and outer circumferences. When the CD-ROM signal processing circuit 64 detects the sync signal of the CD-ROM 60, the sub-header discriminating means 69 discriminates the sub-header and controls the switch circuit 93 to select the destination of the image block and the audio block. The selection control means 74 determines whether to write the voice block to the memory circuit 78 or discard it, and opens or closes the switch circuit 94 based on this determination. The audio data stored in the memory circuit 78, which is a storage unit, is expanded by the expansion circuit 79, and then the DA conversion circuit 80
And is converted into an analog audio signal via the low-pass filter 81 and output. The reproduction method designating unit 75 is an operation unit of the disc reproducing apparatus and specifies a reproduction method such as fast-forward reproduction. When the reproduction method designating unit 75 instructs the fast-forward reproduction, the oscillator 90 multiplies the frequency of the reference clock by m / n.

FIG. 2 is a flowchart of an interrupt processing routine performed by the microprocessor 77 when the CD-ROM signal processing circuit 64 detects a block of the CD-ROM 60. The numbers in parentheses indicate the means of doing so. For example, 69 sub-header discriminating means checks the sub-header in step 100.

FIG. 5 shows audio blocks A1, A2, ... And image blocks D1, D2,
... is a schematic diagram showing the state of reproduction of the CD-ROM 60 recorded at a ratio of 1: 3, and shows the temporal correspondence between the reproduction data read from the CD-ROM 60 and the sound output from the disc reproducing device. . FIG. 5 (a) shows the case where the CD-ROM 60 is reproduced normally by the disc reproducing apparatus shown in FIG.
Shows the case where the fast-forward reproduction is performed by the disc reproducing apparatus in FIG. 1, and FIG. 5 (c) shows the case where the fast-forward reproducing is performed on the CD-ROM 60 by the same method as the fast-forward reproducing performed by the conventional CD player. The relationship between the reproduction data read from the disc and the audio output is shown.

Regarding the disc reproducing apparatus configured as described above,
The operation will be described below.

First, the operation when normal reproduction is performed will be described.

When the normal reproduction is specified by the reproduction method specifying means 75, the oscillator 90 generates the reference clock of 4.3218 MHz. Since the motor control circuit 65 rotates the spindle motor 61 so that the reference clock and the reproduction clock output by the CD signal processing circuit 63 match, the CD-ROM 60 has the same speed as the recording speed, that is, a linear speed of about 1.25 m / Rotate in sec. As a result, CD-ROM
The signal processing circuit 64 outputs an image block or an audio block at a rate of 75 blocks / second. Therefore, the microprocessor 77 operates according to the flowchart of FIG. 2 once in 1/75 seconds. CD-ROM signal processing circuit 64
Microprocessor detects a block of CD-ROM60
An interrupt signal is generated for 77. When the microprocessor 77 receives the interrupt signal, the sub-header discriminating means 69 and the selection control means 74 operate according to the flowchart of FIG.

First, in step 100, the sub-header discriminating means 69 checks the sub-header. That is, the sub-header discriminating means 69 reads the sub-header from the CD-ROM signal processing circuit 64 and discriminates whether it is an image block or an audio block. If it is an image block, the process proceeds to step 113, and the sub-header discriminating means 6
After setting the switch circuit 93 on the image processing output means 92 side, 9 instructs the CD-ROM signal processing circuit 64 to output one block of data in step 111, and in step 112 CD-RO.
The interrupt processing routine ends after waiting for the data transfer of the M signal processing circuit 64 to end.

Now, it is assumed that the reading means 67 reads the audio block from the CD-ROM 60 (time t0, t2, t4, t6, ... In FIG. 5 (a)).
When the audio block is reproduced, the sub-header determining means 69 determines in step 100 that the audio block is an audio block, and
The switch circuit 93 is set to the switch circuit 94 side by 01. In step 102, the selection control means 74 closes the switch circuit 94, and then in step 103, it is judged whether or not the reproduction method designating means 75 is instructing the fast-forward reproduction. In the case of normal reproduction, the transfer interruption flag is set to 0 in step 110, and then
After the block counter is reset in step 114,
Steps 111 and 112 are executed, the voice block is written in the memory circuit 78, and the interrupt processing routine ends. The transfer interruption flag is an internal flag of the selection control means 74, and the audio block is stored in the memory circuit 78 during fast forward reproduction.
Used to determine whether to write to. The block counter is an internal counter of the selection control means 74 used for counting the number of audio blocks during fast-forward reproduction. The audio block written in the memory circuit 78 is expanded by the expansion circuit 79, converted into an analog audio signal through the DA conversion circuit 80 and the low-pass filter 81, and audio output to the outside is started (fifth). Times t1, t3, t5, ... In FIG.

Next, the operation when the fast-forward reproduction is performed will be described.

When the fast forward reproduction is specified by the reproduction method specifying means 75, the oscillator 90 changes the frequency of the reference clock to a frequency higher than 4.3218 MHz. In the present embodiment, a 7.203 MHz reference clock that is 5/3 (m = 5, n = 3) times is generated. Motor control circuit
65 is the reference clock and the CD signal processing circuit as described above.
Since the spindle motor 61 is rotated so that the reproduction clock output by 63 matches, the CD-ROM 60 is
Rotate at 3 times speed. As a result, the CD-ROM signal processing circuit 6
Image block or audio block is output from 4 at a rate of 125 blocks / sec. Therefore, the microprocessor 77 operates according to the flowchart of FIG. 2 once in 1/125 second.

When the image blocks of V1, V2, ... Are read from the CD-ROM 60, the data of all the image blocks are sent to the image processing output means 92, as in the case of normal reproduction. The image processing output means 92 takes in the sent image data into an internal image memory (not shown), converts it into a video signal, and outputs it to the outside.

Now, it is assumed that the reading means 67 reads data from the audio block A1 at a speed 5/3 times as high as the normal speed (see FIG. 5 (b)). When the audio block of A1 is reproduced, the value of the block counter is set to 1 through steps 100, 101, 102, 103 and 104 (time t21), and the value of the transfer interruption flag is checked in step 105. Before the fast-forward reproduction is started, the transfer interruption flag is set to 0 in step 110, so the flow advances to step 106 to compare the value of the block counter with n. Since the block counter is 1 and n = 3, the process proceeds to step 111, and after executing step 112, the interrupt processing routine ends. After that, time t2
The audio block from 2 to A1 is converted to audio and output to the outside.

Even if the audio block of A2 is played at time t23, A
The same processing is performed as when the audio block of 1 is reproduced. However, the value of the block counter is 2.

When the audio block A3 is reproduced at time t25, the value of the block counter is 3, which is equal to n, and therefore the transfer interruption flag is set to 1 in step 107. After that, the block counter is reset to 0 in step 114, and the memory circuit 78 is reset to A3 through steps 111 and 112.
Audio block is written.

When the audio block of A4 is reproduced at time t26, the block counter becomes 1 in step 104. Since the transfer interruption flag is set to 1 at time t25, as a result of checking in step 105, step 108 is executed and the switch circuit 94
Is opened. Next, at step 109, it is checked whether the value of the block counter has reached mn. Since mn = 2, the process proceeds to step 111, and the subheader discriminating means 69
After instructing the CD-ROM signal processing circuit 64 to output one block of data, the transfer end is checked at 112. During this transfer, the switch circuit 94
Since A is opened, the audio block of A4 is not written in the memory circuit 78 and is discarded.

At time t28, when the audio block of A5 is played back, the same processing as at time t26 is performed until step 108.
109 is executed. Since the block counter is 2, which is equal to the value of mn, the routine proceeds to step 110, where the transfer interruption flag is set to 0. Next, after the block counter is reset to 0 in step 114, the audio block of A5 is discarded similarly to the audio block of A4 through steps 111 and 112.

When the audio block A6 is reproduced at time t29, the transfer interruption flag is 0 and the block counter is 0. Therefore, the interrupt processing routine performs the same process as the audio block A1. After that, when the audio blocks A7, A8, A9, and A10 are reproduced, the same processing as that when the audio blocks A2, A3, A4, and A5 are reproduced is performed in the interrupt processing routine.

That is, during fast-forward playback, audio blocks are read from the CD-ROM 60 every 4/125 seconds, and 5 consecutive blocks (20/1
25 seconds), 2 blocks of voice blocks are discarded. Audio data for 4/75 seconds is recorded in each audio block, and audio data for 12/75 seconds is recorded in three audio blocks that are output as audio without being discarded. This value is 12/75 = 4/25 = 20/125,
Since the audio block of 5 blocks is equal to the time length read from the CD-ROM 60, the audio output is not interrupted during the fast forward reproduction.

As described above, according to the present embodiment, the separating means for separating and outputting the data output from the reading means for each block, and the selecting means for controlling the sending of the audio block output from the separating means to the next stage. A storage means for temporarily storing the voice block output from the selecting means, and a voice processing output means for sequentially reading the voice blocks stored in the storage means, performing a decompression process, and converting the voice block into an analog voice signal for output. When the reproduction method designating unit instructs the fast-forward reproduction, the rotation speed for realizing the recording speed is m / n times (m
> N) motor control means for rotating the motor at a rotation speed, and selection control means for controlling the selection means so as to send n blocks of audio blocks to the next stage from among m blocks of continuous audio blocks separated by the separation means. By providing and, all the data is read out at high speed by rotating the disc at high speed without performing track jump during fast-forward playback, and extra audio blocks are adaptively discarded, so that the silent period during fast-forward playback becomes zero. Become. Further, with regard to the image blocks, all the image blocks are sent to the image processing output means, so that a screen lacking a part is not displayed during fast-forward reproduction.

In the above-described embodiment, m = 5 and n = 3 have been described, but m, n is not limited to this value and may be m> n. For example, m = 2, n = 1 or m = 5, n = 2. In these cases, data may be read out from the CD-ROM 60 at a speed of 2 times and 5/2 times, respectively, and audio blocks may be discarded at a ratio of 1 block to 2 blocks and 3 blocks to 5 blocks.

In addition, in the above-mentioned embodiment, the CD
-The operation has been described assuming that the number of channels of the image block and the audio block recorded in the ROM is 1, but a CD-ROM disc in which the audio blocks of a plurality of channels and the image blocks of a plurality of channels are recorded may be used. In this case,
The sub-header discriminating means 69 may check the file number and the channel number and discard the blocks other than the desired channel.

Further, in the above-described embodiment, the CD-ROM disc is described as an example of the disc, but any disc may be used as long as it can record the audio block including the audio data compressed on the time axis at a predetermined recording speed. For example, it can be applied to various discs such as a writable CD-ROM and a magneto-optical disc.

As described above, according to the present invention, when the disc is fast-forwarded and reproduced, the track jump is not performed, and the rotation speed of the disc is m /
By raising all times to n times (m> n) to read all the data at high speed and adaptively discarding the voice block, it is possible to eliminate the silence period of the voice caused by the track jump. Further, regarding the image blocks recorded in time division with the audio blocks, all the image blocks are sent to the image processing output means,
A screen with a part missing is not displayed at the time of fast-forward reproduction, and a complete screen is displayed, which has a great practical effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a disc reproducing apparatus according to the first embodiment of the present invention, FIG. 2 is a flow chart of an interrupt processing routine executed by the microprocessor 77 of FIG. 1, and FIG. 3 is a conventional disc. CD as a playback device
FIG. 4 is a block diagram showing the internal structure of the player, FIG. 4 is a flowchart of an interrupt processing routine performed by the microprocessor 84 of FIG. 3, and FIG. 5 is a state of reproduction of the CD-ROM 60 in which audio blocks and image blocks are recorded. Pattern diagram,
Fig. 6 is a format diagram of the data recorded on the CD, Fig. 7
The figure is a format diagram of data recorded on a CD-ROM. 60 …… CD-ROM, 61 …… motor, 67 …… reading means, 70 ……
Separation means, 74 ... Selection control means, 75 ... Reproduction method designating means, 78 ... Memory circuit (storage means), 82 ... Voice processing output means, 92 ... Image processing output means, 94 ... Switch circuit ( Selection means).

Claims (2)

[Claims] 1. A reading unit for reading data from a disc on which an audio block containing time-compressed audio data is recorded at a predetermined recording speed, a motor for rotating the disc, and data output by the reading unit. Separating means for separating the audio block from the, the audio block output from the separating means, a selecting means for controlling to send to the next stage, a storage means for temporarily storing the audio block output from the selecting means, Audio processing output means for sequentially reading the audio blocks stored in the storage means, performing decompression processing, and then converting the analog audio signals for output, a reproduction method specification means for specifying a reproduction method, and the reproduction method specification When the means instructs the fast-forward reproduction, the rotational speed for realizing the recording speed is m / n times (m is 2
The above integer, n is an integer greater than or equal to 1 and a motor control unit that rotates the motor at a rotation speed of m> n), and the separation unit separates when the reproduction method designating unit instructs fast-forward reproduction. And a selection control means for controlling the selection means so as to send n blocks of audio blocks to the next stage among the continuous m blocks of audio blocks. 2. A reading means for reading data from a disc recorded at a predetermined recording speed by time-multiplexing an audio block containing audio data compressed in time axis and an image block containing image data, and rotating the disk. A motor, a separating unit that separates the data output by the reading unit into an audio block and an image block, and an image block output from the separating unit,
Image processing output means for converting into a video signal for output, selection means for controlling the audio block output from the separation means to the next stage, and temporarily storing the audio block output from the selection means Storage means, audio processing output means for sequentially reading out the audio blocks stored in the storage means, performing decompression processing, and then converting and outputting to an analog audio signal; reproduction method specifying means for specifying a reproduction method; When the reproduction method designating unit instructs the fast-forward reproduction, m / n times the rotation speed for realizing the recording speed (m is 2
The above integer, n is an integer greater than or equal to 1 and a motor control unit that rotates the motor at a rotation speed of m / n), and the separation unit separates when the reproduction method designating unit instructs fast-forward reproduction. And a selection control means for controlling the selection means so as to send n blocks of audio blocks to the next stage among the continuous m blocks of audio blocks.