JPH0476859A - Disk reproducing device - Google Patents

Abstract

PURPOSE:To eliminate a silent period of a voice due to a track jump by reading all data at high speed in gathering a rotating speed of a disk without jumping a track at the time of fast forward reproducing the disk and abandoning a sound block. CONSTITUTION:The disk reproducing device is constitutive of a selecting means 94 for controlling on sending a sound block outputted from a separating means 70 for separating and outputting each block from a data outputted by a read means to the next stage, a storage means 78 for storing temporarily sound blocks outputted from the selecting means 94, a sound processing output means 82 for reading the sound blocks in turn and converting them into analog sound signals to be outputted after performing their expanding processing, a motor control means 65 for rotating a motor 61 at a rotating speed of m/n times (m>n) as much as a rotating speed for realizing a recording speed when the fast forward reproducing is indicated by a reproducing method specifying means 75 and a selecting control means 74 for controlling the selecting means 94 to send sound blocks of n-blocks out of sound blocks of continuous m-blocks separated by a separating means 70 to the next stage. Sound blocks written in the storage means 78 are read out in turn by the sound processing means 82, and after expanding processing they are converted into analog sound signals and then outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION 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.

Conventional technology In recent years, compact discs (hereinafter abbreviated as CDs) have become popular.
has become widespread, and compact disk read-only memory (hereinafter abbreviated as CD-ROM) is also beginning to become popular as a new development of CDs. CD has a sampling frequency of 44. It records the audio of the first stereo channel (hereinafter abbreviated as CD-DA data) converted into a digital signal at 1 KHz and 16 quantization bits. Instead of data, image data, computer programs, audio data, etc. are structured and recorded.

An example of a conventional disc playback device will be described below with reference to the drawings.

First, the data formats of CDs and CD-ROMs will be explained using FIGS. 6 and 7.

Figure 6 shows the format of data recorded on a CD; (a) is a schematic diagram of a data frame, which is the minimum recording unit; (b) is a schematic diagram of a subcode frame; (C
) is a schematic diagram of the Q channel data format in the program area. Figure 7 shows the format of data recorded on the CD-ROM, and (a) shows the format of the data recorded on the CD-ROM.
- Schematic diagram of the data format of audio blocks recorded in mode 2 of ROM, (b) is a schematic diagram of the subheader of mode 2 of CD-ROM, (C) is the arrangement of audio blocks recorded in CD-ROM FIG.

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

One data frame includes subchannel 2 and main channel 1, and is recorded on a CD in a time-division manner. The subchannel 2 has a 1-byte data recording area, and the main channel 1 has a 32-byte data recording area, including a 24-byte data 3 and an 8-byte error detection and correction code 4.

On a CD, CD-DA data is recorded at the data 3 position. These data frames are recorded on the CD at a rate of 7350 data frames/second. The error detection and correction code 4 is a code for detecting and correcting data errors in the main channel 1 data.

Before recording these data on a CD, EFM (Ei
ght-to-Fourteen-M.

Duration (eight-to-fourteen modulation) modulation, addition of a data frame synchronization signal to identify data frame boundaries, etc. are performed. As a result, one data frame is 588 bits, and the bit rate when recorded on a CD is 588x7.
350=4.3218 Mbit/sec. This data is in the form of an NRZi signal at a constant speed (approximately 1.25
m/5ec) and is recorded spirally from the inner circumference to the outer circumference.

A subcode frame is composed of subchannel 2 of 98 continuous data frames. There are 75 sub-food frames per second. This situation is shown in FIG. 6(b). The first two data frames of subchannel 2 constitute a subcode frame synchronization 7, and the remaining 96 data frames of subchannel 2 record data called subcodes. Each bit of one byte of the subcode corresponds to a channel, and these channels are called P channel, Q channel, . . . , W channel.

An address is recorded in the Q channel 9 (see FIG. 6(C)). The address is the beginning of the program area.
Absolute time (AMIN, ASEC) that increases toward the outer circumference as minutes, seconds, and frames.

AFRAME), relative time (MIN, SEC, FRAME) with the beginning of each track as 0 minutes 0 seconds 0 frame, track number, and index, each of which is recorded in BCD code (binary coded decimal number). There is.

A frame here is a unit of time, and 75 frames corresponds to one second. That is, a frame as a unit of time is equal to the time length of one subcode frame.

In a CD-ROM, data for 98 data frames corresponding to the length of one subcode frame is 98X24=2
Structuring is performed using 352 bytes as one block (see Figure 7 (a)). Each block has a 12-byte synchronization signal at the beginning to identify the block break.
There is a 4-byte header following the synchronization signal. The first three bytes of the header are called a physical block address, and an absolute address is recorded with the beginning of the program area being 090 seconds and 0 blocks. This absolute address is shown in Figure 6(c).
Absolute time (AMIN, ASEC, APRAM
The value is equal to E). The last byte of the header indicates the mode, and the recorded contents of the remaining 2336 bytes vary depending on this value.

That is, in the CD-ROM, the synchronization signal, header, subheader, user data, etc. shown in FIG. 7(a) are recorded instead of the CD-DA data.

FIG. 7(a) shows the data format of a mode 2 audio block. In mode 2, an 8-byte subheader is recorded following the header (see FIG. 7(b)).

A file number for identifying the file is recorded in the O-th byte and the fourth byte. Channel numbers are recorded in the first and fifth bytes to further define the same file. Submodes are recorded in the second and sixth bytes. This sub-mode byte is bit enhooded, and the type of data recorded in this block is recorded. For example, a code for identifying whether the data recorded in this block is image data or audio data is recorded in the submode byte. Hereinafter, a block in which image data is recorded at the user data position will be abbreviated as an image block. Further, a block in which audio data is recorded will be abbreviated as an audio block hereinafter. The coding information recorded in the third and seventh bytes differs depending on the value of the submode byte. In the coding information byte of the audio block, the audio level indicating the evening sound quality, the monaural/stereo distinction, etc. are recorded.

As the coding information of the image block, an identifying code indicating the format of the image data is recorded.

In the 2324-byte user data area of the audio block, 18 128-byte Sara/Nand groups are recorded.
0 is recorded in the remaining 20 bytes. Each sound group records 16 bytes of sound parameters, which are audio data parameters used for decoding processing, and 112 bytes of sound data, which is actual audio data.

There are 3N types of compression methods, level A, level B, and level C, depending on the difference in sampling frequency and number of bits, and each level has a monaural/stereo distinction, so there are 6 types in total.
There are several types of compressed audio formats. The data amount of level A stereo is compressed to about 1/2 compared to the audio of a CD. The amount of data for level A monaural and level B stereo is compressed to about 1/4 of the CD audio. The amount of data for level B monaural and level C stereo is compressed to about 178 compared to CD audio. The data amount of Level C monaural audio is compressed to about 1/16 of the CD audio. Therefore,
With level B stereo, four channels of stereo sound can be recorded on a CD-ROM. It is also possible to time-axis multiplex and record audio blocks and image blocks. This situation is shown in FIG. 7(C). In the figure, for example, in the case of level C monaural, the amount of data is compressed to about 1716, so one audio block is recorded in every 16 blocks, and the remaining 1
By recording image data in 5 blocks, it is possible to realize an electronic picture-story show that changes images while outputting sound. Furthermore, the concept of channels can be introduced not only for audio but also for images, and images of multiple channels can be recorded on a CD-ROM.

In this way, when audio blocks and image blocks are recorded on a CD-ROM, they are recorded in a time-division manner so that audio blocks belonging to the same channel are arranged at regular intervals. During playback, the block whose file number and channel number both match the specified values 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 output as audio. It is converted into a video signal by an image processing circuit and output (for example, Electronics, December 1985 issue, pages 55 to 60).

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

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

FIG. 3 is a block diagram showing the internal configuration of a CD player, which is a conventional disc playback device. In FIG. 3, a spindle motor 61 rotates a CD 59 at a constant linear velocity, and a pickup 62 reads signals 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.

The motor control circuit 98 is a CLV (Constant Linear Vessel) that controls the rotation of the spindle motor 61.
locity: constant linear velocity)
Perform servo. This CLV servo is the CD signal processing circuit 6
The recovered clock extracted within 3 is made to match the reference clock of 4,3218 MHz output by the oscillator 97. The pickup control circuit 6B includes a focus servo that focuses the reading laser beam on the CD 59, a tracking servo that causes the reading laser beam to follow a recording track formed in a spiral shape on the CD 59, and a traverse servo that moves the pickup 62 to the inner and outer peripheries. I do. CD-D output from the CD signal processing circuit 63
The A data is converted into an analog audio signal via a DA conversion circuit 80 and a low-pass filter 81 and output. The permission means 85 determines whether a track jump is allowed or not, and the playback speed control means 83 outputs a track jump command to the pickup control circuit 66. A playback method specifying means 75 specifies a playback method such as fast-forward playback using the operation section of the CD player.

Reproduction speed control means 83. Specifically, the operations performed by the permission means 85 are realized by a program executed by the microprocessor 84.

FIG. 4 is a flowchart of an interwoven processing routine performed by the microprocessor 84 when the CD signal processing circuit 63 detects subcode frame synchronization 7. 0
The numbers in the box indicate the means to execute it. For example, the operation of incrementing the internal counter in step 200 is performed by the enabling means 85.

The operation of the disc playback device configured as described above will be described below.

First, when the CD signal processing circuit 63 detects subcode frame synchronization 7 during playback of the CD 59, it generates an interlaced signal to the microprocessor 84. When the microprocessor 84 receives the interwoven signal, the microprocessor 84 processes the permission means 85 . The reproduction speed control means 83 operates. First, in step 200, the permission means 85 increments an internal counter. Next, in step 201, the reproduction speed control means 83 determines the state of the reproduction method specifying means 75. Assuming that the fast-forward playback switch of the playback method specifying means 75 is not pressed, the included processing routine ends.

That is, while normal playback is being performed, only the internal counter is incremented by the permission means 85.

When the included processing routine is executed after the fast-forward playback switch is pressed, the process advances to step 202.
In step 202, the reproduction speed control means 83 controls the permission means 85.
Check the value of the counter inside and determine whether it is greater than or equal to a predetermined value. If it is larger than the predetermined value, the reproduction speed control means 8
3 outputs a track jump command to the pickup control circuit 68 in step 203, and then the permission means 8
5 clears the internal counter in step 204, and the interwoven processing routine ends. For example, set this predetermined value to 10
If this is the case, a track jump command will be output approximately every 10/75 seconds.

When the pickup control circuit 66 receives the track jump command, it controls the pink-up 62 to jump the playback position in the outer circumferential direction. For example, 1 toward the outer circumference.
Pickup control circuit to make this truck jump 6
6 controls the pink up 62, the pickup 62
moves the playback position to the outer adjacent track. CD5
Since the signal is recorded from the inner circumference to the outer circumference in case 9, the playback position advances by the above operation, and as a result, fast-forward playback is realized.

When the pickup 62 performs a track jump, the continuity of the reproduced data is lost, resulting in a momentary interruption of the audio output.

Problems to be Solved by the Invention Since CD-DA data is recorded continuously on a CD, when playing fast forward on a CD player, even if the above-mentioned method is used, the audio may be interrupted due to track jumps. Time is very short. However, if the above-described method is directly applied to a playback device for a disc in which audio blocks and image blocks are recorded discretely, a problem arises in that the audio interruption time due to a track jump becomes long. That is, if track jumps are performed at regular time intervals, the silent period due to track jumps becomes long. Furthermore, since the image data constituting one screen is distributed and recorded in a plurality of image blocks, there is also the problem that some of the image blocks constituting the screen are not reproduced and the display screen is distorted.

This problem will be explained using FIG. 5. FIG. 5 is a schematic diagram showing how a CD-ROM in which audio blocks and image blocks are recorded is played back.

This CD-ROM has one audio block and one image block.
recorded at a ratio of 3:3. Each audio block has 4/
75 seconds of audio data is recorded. A1. A2
．． A3. ...indicates an audio block,
VL V2. V3. ... indicates an image block. When playing this disc normally, the 5th
As shown in Figure (a), after reading the A1 block from the CD-ROM, the audio data is decompressed and 47
Outputs 75 seconds of audio. By the time the decompression processing of the A1 block ends, the next A2 block will have been reproduced from the disk, and the audio will be reproduced without interruption.

Further, the image blocks are sent to an image memory, and one display screen is displayed using the image data in the plurality of image blocks. Now, let us consider a case where fast-forward playback is performed using the same method as in a conventional CD player. In this case, the timing of the track jump is determined by the elapsed time since the previous track jump, and is therefore performed regardless of the type of data read from the disk. Therefore, for example, as shown in FIG. 5(C), after reading the image block of V5, a track jump operation is performed at time t41, and V
When playback is restarted from block ll, there is a silent period until the data of block A5 is decompressed and output. Let Tj be the time during which data cannot be read from the disk due to a track jump, and Ts be the time length of one block.
Assuming that audio data is time-divisionally recorded every n blocks, when a track jump is performed at an arbitrary timing, the silent period Tm satisfies the relationship Tm<(n+1)Ts+Tj. For example, in the case of mode C monaural described above, n=16, so even if Tj=0, the maximum value is about 0. A silent period of 2 seconds will occur. Furthermore, since the image blocks from V6 to vlo are not reproduced, a screen with a portion missing will be displayed.

In view of the above problems, the present invention aims to provide a disc playback device in which the sound is not interrupted and a complete image is always displayed when fast-forwarding a disc on which audio blocks and image blocks are recorded discretely. purpose.

Means for Solving the Problems In order to achieve the above object, the disc playback device of the present invention includes a separating means for separating and outputting each block from the data outputted by the reading means, and an audio block outputted from the separating means. , a selection means for controlling transmission to the next stage, a storage means for temporarily storing the audio blocks output from the selection means, and an analog audio When the audio processing output means for converting into a signal and outputting the signal and the reproduction method specifying means instruct fast-forward reproduction, the rotation speed is m/n times (m>n) the rotation speed that realizes the recording speed. It is composed of a motor control means for rotating a motor, and a selection control means for controlling a selection means so as to send to the next stage n blocks of audio blocks from among the m blocks of consecutive audio blocks separated by the separation means. .

According to the above-described structure, the present invention rotates the disc at a speed m/n times that of normal playback during fast-forward playback, and the selection control means selects n audio blocks from among m consecutive audio blocks to the next stage. The selection means discarded or sent the audio blocks to the storage means according to the instructions of the selection control means, and the audio processing means sequentially read out the audio blocks written in the storage means and performed decompression processing. After that, it will be converted to an analog audio signal and output.

Embodiment Hereinafter, a disc playback device according to an embodiment of the present invention will be described.
This will be explained with reference to FIGS. 1, 2, and 5. 1st
The figure is a block diagram showing the configuration of a disc playback device in an embodiment of the present invention.

In FIG. 1, a CD-ROM 80 is a disk on 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 f32. CD
Signal processing circuit 63. CD-ROM signal processing circuit 64. It is composed of a pickup control circuit 66. Separation means 70
is composed of a switch circuit 93 and subheader discrimination means 69.

The audio processing output means 82 includes an expansion circuit 79. DA conversion, circuit 80. It is composed of a low-pass filter 81.

The motor control means 91 includes a motor control circuit 659 and an oscillator 90.
It consists of Further, the subheader discrimination means 691 selection control means 74 is realized by a program executed by the microprocessor 77. The spindle motor 61 is CD-
The ROM 60 is rotated and the pickup 62 reads the CD-RO.
Read the signal recorded in M60. The read signal is converted into a digital signal by the CD signal processing circuit 63, and then
Error detection and correction processing is performed. Thereafter, the CD-ROM signal processing circuit 64 performs processing such as detection of a synchronization signal of the CD-ROM format. The motor control circuit 65 performs CLV servo to control the rotation of the spindle motor 61. This CLV servo is performed so that the reproduced clock extracted within the CD signal processing circuit θ3 matches the reference clock output from the oscillator 90. Pickup control circuit 6
6 is a focus servo that focuses the reading laser beam on the CD-ROM 60, a tracking servo that causes the reading laser beam to follow a recording track formed spirally on the CD-ROMeO, and a traverse that moves the pickup 62 to the inner and outer peripheries. Perform servo. CD-R
When the OM signal processing circuit 64 detects the synchronization signal of the CD-ROM 60, the subheader determining means 69 determines the subheader and controls the switch circuit 93 to select the destination of the image block and audio block. The selection control means 74 determines whether to write the audio block into the memory circuit 78 or discard it, and opens and closes the switch circuit 94 based on this determination. The audio data stored in the memory circuit 78, which is a storage means, is decompressed in the decompression circuit 79 and then transferred to the DA.
It is converted into an analog audio signal via a conversion circuit 80 and a low-pass filter 81 and output. Reproduction method specification means 7
S is an operation unit for disc playback, and specifies a playback method such as fast-forward playback. When the reproduction method specifying means 75 instructs fast-forward reproduction, the oscillator 90 changes the frequency of the reference clock to m.
/ Multiply by n.

In FIG. 2, the CD-ROM signal processing circuit 64 is
When 80 blocks are detected, microprocessor 7
7 is a flowchart of the included processing routine performed by No. 7. The number within 0 indicates the means to perform it. For example, it is the subheader determination means 69 that checks the subheader in step 100.

FIG. 5 shows audio blocks Al, A2. ...and image blocks DI, D2. .
It shows the temporal correspondence between playback data read from the D-ROM 60 and audio output from the disk playback device. FIG. 5(a) shows that when the CD-ROM 80 is normally played back by the disk playback device of FIG. 1, FIG. 5(b) shows
Fig. 5 (C) shows the case where fast-forward playback is performed with the disc playback device shown in Fig. 1, and Fig. 5 (C) shows the case when fast-forward playback of CD-ROM 60 is performed using the same method as the fast-forward playback performed in a conventional CD player. It shows the relationship between playback data read from the disc and audio output.

The operation of the disc playback device configured as described above will be described below.

First, the operation when normal playback is performed will be explained.

When normal reproduction is specified by the reproduction method specifying means 75, the oscillator 90 generates a reference clock of 4.3218 MHz. The motor control circuit 65 rotates the spindle motor 61 so that the reference clock and the reproduced clock output from the CD signal processing circuit 63 match.
is the same speed as the recording speed, i.e. linear velocity 1.25 m/s
Rotate with ec. As a result, the CD-ROM signal processing circuit 64 outputs image blocks or audio blocks at a rate of 75 blocks/second. Therefore, the microprocessor 77 performs the operation according to the flowchart of FIG. 2 once every 1/75 seconds.

When the CD-ROM signal processing f1 circuit 64 detects a block of the CD-ROM 60, it generates an interwoven signal to the microprocessor 77. microprocessor 7
7 receives the interwoven signal, subheader discrimination means 691 selection control means 7 according to the flowchart of FIG.
4 works.

First, in step 100, the subheader determining means 69 checks the subheader. That is, the subheader discrimination means 6
9 reads the subheader from the CD-ROM signal processing circuit 64 and determines whether it is an image block or an audio block.

If it is an image block, the process proceeds to step 113, and the subheader determination means 69 sets the switch circuit 93 to the image processing output means 92 side, and then, in step 111, the subheader determination means 69 sets the switch circuit 93 to the image processing output means 92 side.
The M signal processing circuit 64 is instructed to output one block of data, and at step 112, the interleaved processing routine ends after waiting for the data transfer of the CD-ROM signal processing circuit 64 to be completed.

Now, the reading means 67 reads the audio block from the CD-ROM 80.
(time to in FIG. 5(a),
t2. t4. t8. ...). When the audio block is played back, the subheader determining means 69 determines in step 100 that it is an audio block, and in step 101
The switch circuit 93 is set to the switch circuit 94 side.

In step 102, the selection control means 74 selects the switch circuit 84.
After closing, in step 103, it is determined whether the reproduction method specifying means 7S is instructing fast-forward reproduction. In the case of normal playback, the transfer interruption flag is set to O in step 110, then the block counter is reset in step 114, and then step 1111 is executed to write the audio block to the memory circuit 78. The interwoven processing routine ends. The transfer interruption flag is an internal flag of the selection control means 74, and is used to determine whether or not to write the audio block to the memory circuit 78 during fast-forward playback. The block counter is an internal counter of the selection control means 74 used to count the number of audio blocks during fast-forward playback. The audio block written in the memory circuit 78 is sent to the decompression circuit 79.
The decompression process is carried out at 80°, and the signal is converted into an analog audio signal via the DA conversion circuit 80° low-pass filter 81, and audio output to the outside is started (at time t1 in FIG. 5(a)).
t3. t5. ...)0 Next, the operation when fast forward playback is performed will be explained.

When fast-forward playback is specified by the playback method specifying means 75, the oscillator 90 changes the frequency of the reference clock to 4°3218MHz.
Change to a higher frequency. In this example, 5/3 (
m=5. A reference clock of 7.203 MHz, which is 7.203 MHz (n=3) times, is generated. The motor control circuit 65, as described above,
In order to rotate the spindle motor 61 so that the reference clock and the reproduced clock output from the CD signal processing circuit 63 match, the CD-ROM f30 rotates at a speed 5/3 times the recording speed. As a result, the CD-ROM signal processing circuit 64 outputs image blocks or audio blocks at a rate of 125 blocks/second. Therefore, the microprocessor 77 performs the operation according to the flowchart of FIG. 2 once every 1/125 seconds.

Vl, V2.・l) Image block is CD-RO
When read from the M60, all image block data is sent to the image processing output means 9 as in the case of normal playback.
Sent to 2. The image processing output means 92 captures the sent image data into an internal image memory (not shown), converts it into a video signal, and outputs it to the outside.

Now, suppose that the reading means 67 reads data from the audio block A1 at a speed 573 times the normal speed (5th
(See figure (b)). When audio block A1 is played,
Steps 100, 101, 102, 103. 104
After that, the value of the block counter is set to 1 (at time t2
1L Step! At step 05, the value of the transfer interruption flag is checked. Step 11 before fast forward playback starts
Since the transfer interruption flag is set to 0 at 0, the process advances to step 106 and the value of the block counter is compared with n. Now, since the block counter is 1 and n=3, the process advances to step 111, and after executing step 112, the interwoven processing routine ends.

Thereafter, from time t22, the audio block A1 is converted into audio and output to the outside.

When the audio block A2 is played back at time t23, the same process as when the audio block A1 is played back is performed. However, the value of the block counter is 2.

When audio block A3 is played back at time t25, the value of the block counter is equal to n and is 3, so
At step 107, the transfer interruption flag is set to 1. Thereafter, the block counter is reset to O in step 114, and the audio block A3 is written into the memory circuit 78 through steps 111 and 112.

When the A4 audio block is reproduced at time t26, the block counter becomes 1 in step 104. Time t25
The transfer interruption flag is set to 1 in step 1.
As a result of the check at step 05, step 108 is executed and the switch circuit 94 is opened. Next, in step 109, it is checked whether the value of the block counter has reached m-n. Since m-n=2, the process proceeds to step 111, where the subheader determining means 69 instructs the CD-ROM signal processing circuit 64 to output one block of data, and then checks 112 whether the transfer is complete. During this transfer, since the switch circuit 94 is opened in step 108, the A4 audio block is not written to the memory circuit 78 and is discarded.

When the audio block A5 is played back at time t28, the same processing as at time t26 is performed up to step 108,
Step 109 is executed. The block counter is 2, which is equal to the value of m n, so step 110
The transfer interruption flag is set to O. Next, after the block counter is reset to 0 in step 114,
After steps 111 and 112, the A5 audio block is discarded like the A4 audio block.

When the audio block A6 is played back at time t29, since the transfer interruption flag is 0 and the pronk counter is 0, the same processing as the audio block A1 is performed in the interwoven processing routine.

Hereafter, A7. A8. A9. When the AIO audio blocks are played, the interwoven processing routine
．． A3. A4. The same process as when audio block A5 is played back is performed.

That is, during fast-forward reproduction, an audio block is read from the CD-ROM 60 every 4/125 seconds, and two audio blocks out of five consecutive blocks (20/125 seconds) are discarded. Each audio block records 4/75 seconds worth of audio data, and 12/75 seconds worth of audio data is recorded in the three audio blocks that are output as audio without being discarded. This value is 12/7
5=4/25=20/125, which is equal to the length of time for 5 audio blocks to be read from the CD-ROM 60, so the audio output will not be interrupted even during fast-forward playback.

As described above, according to this embodiment, the separating means separates and outputs each block from the data outputted by the reading means;
a selection means for controlling sending the audio blocks output from the separation means to the next stage; a storage means for temporarily storing the audio blocks output from the selection means; and sequential reading of the audio blocks stored in the storage means; After decompression processing,
When the audio processing output means for converting into an analog audio signal and outputting it, and the playback method specifying means instruct fast-forward playback, the rotation speed to achieve the recording speed is m70 times (m>
n) a motor control means for rotating the motor at a rotational speed of n), and a selection means for controlling the selection means to send n blocks of audio blocks from among the m consecutive audio blocks separated by the separation means to the next stage. By providing a control means, during fast-forward playback, the disk is rotated at high speed without performing a track jump, and all data is read out at high speed.
Since redundant audio blocks are adaptively discarded, the silent period during fast-forward playback becomes O. Furthermore, since all image blocks are sent to the image processing output means, a screen with a portion missing will not be displayed during fast-forward playback.

In addition, in the above-mentioned embodiment, m=5. Although the explanation has been made with n=3, m+n is not limited to this value and may be m>n. For example, m ” 2 + n = 1, m = 5,
It may be n==2. In each of these cases, twice,
It is sufficient to read data from the CD-ROM 60 at 5/2 times the speed and discard audio blocks at a rate of 1 block for every 2 blocks and 3 blocks for every 5 blocks.

In addition, in the above embodiment, in order to simplify the explanation, CD
- Although the operation has been explained assuming that the number of channels of image blocks and audio blocks recorded in the ROM is one, a CD-ROM disc may be used on which audio blocks of a plurality of channels and image blocks of a plurality of channels are recorded. In this case, the subheader discriminating means 69 checks the file number and channel number, and discards blocks other than the desired channel.

Further, in the above embodiment, a CD-ROM disk was used as an example of the disk, but any disk may be used as long as it can record audio blocks containing time-axis compressed audio data at a predetermined recording speed. For example, it can be applied to various types of disks such as writable CD-ROMs and magneto-optical disks.

Effects of the Invention As described above, the present invention does not perform a track jump when playing a disc in fast forward, and the rotational speed of the disc is increased by m7.
By increasing the speed by a factor of 0 (m>n) to read all data at high speed and adaptively discarding audio blocks, it is possible to eliminate audio silent periods caused by track jumps. In addition, regarding image blocks that are recorded in time-sharing with audio blocks, all image blocks are sent to the image processing output means, so there will be no partial screen display during fast-forward playback, and complete images will not be displayed. The practical effect is great because the screen is displayed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a disc playback device according to a first embodiment of the present invention, FIG. 2 is a flowchart of an interactive processing routine performed by the microprocessor 77 of FIG. 1, and FIG. A block diagram showing the internal configuration of a CD player, which is a playback device, FIG. 4 is a flowchart of an interconnected processing routine performed by the microprocessor 84 of FIG. 3, and FIG. FIG. 6 is a schematic diagram showing the state of reproduction, FIG. 6 is a format diagram of data recorded on a CD, and FIG. 7 is a format diagram of data recorded on a CD-ROM. 60...CD-ROM1 61...Motor,
67...reading means, 70...separation means,
74...Selection control means, 75...Reproduction method designation means, 78...Memory circuit (storage means), 8
2... Audio processing output means, 92... Image processing output means, 94... Switch circuit (selection means). Name of agent: Patent attorney Shigetaka Awano Haka 1 person wa fig.

Claims (2)

[Claims] (1) reading means for reading data from a disk on which audio blocks including time-axis compressed audio data are recorded at least at a predetermined recording speed; a motor for rotating the disk; and audio from the data output by the reading means. separation means for separating blocks; selection means for controlling sending the audio blocks output from the separation means to the next stage; storage means for temporarily storing the audio blocks output from the selection means; and the storage. an audio processing output means for sequentially reading audio blocks stored in the means, decompressing them, converting them into analog audio signals and outputting the same; a reproduction method specifying means for specifying a reproduction method; the reproduction method specifying means When fast-forward playback is instructed, the motor is rotated at a rotation speed m/n times the rotation speed that achieves the recording speed (m is an integer of 2 or more, n is an integer of 1 or more, m>n). and a motor control means for transmitting n blocks of audio blocks from among consecutive m blocks of audio blocks separated by the separation means when the playback method specifying means instructs fast-forward playback. A disc playback device comprising: selection control means for controlling the selection means. (2) a reading means for reading data from a disk recorded at a predetermined recording speed by time-axis multiplexing an audio block containing time-axis compressed audio data and an image block containing image data; and a motor for rotating the disk. , separating means for separating the data outputted by the reading means into an audio block and an image block; receiving the image block outputted from the separating means;
an image processing output means for converting and outputting a video signal; a selection means for controlling sending the audio block output from the separation means to the next stage; and temporarily storing the audio block output from the selection means. a storage means; an audio processing output means for sequentially reading the audio blocks stored in the storage means, decompressing them, converting them into analog audio signals and outputting the same; and a reproduction method specifying means for specifying a reproduction method; When the playback method specifying means instructs fast-forward playback, the rotation speed is m/n times the rotation speed that achieves the recording speed (m is an integer of 2 or more, n is an integer of 1 or more, and m>n). motor control means for rotating the motor at a speed; and when the playback method specifying means instructs fast-forward playback, the separation means selects n blocks of audio blocks from among the continuous m blocks of audio blocks separated. A disc playback device comprising: selection control means for controlling the selection means so as to send the data to the next stage.