JPH11232785A - Reproducing device and reproducing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform inverse reproduction without increasing program capacity and reducing processing speed or by suppressing the extent to the absolute minimum, in a digital voice reproducing device. SOLUTION: An audio data generating section 21 generates ATRAC thawing data as reproduced digital audio data from MD, and outputs it making a data block as a unit. And at the time of inverse reproduction, pseudo inverse reproduction output in which the order of output of data blocks is reversed to the order at the time of normal reproduction is performed. A data arrangement conversion section 22 refers to a block leading data output timing signal, and converts the order of sampling data in the data block to the inverse order by controlling writing/reading for each data block for a storage circuit 23 provided with a ring buffer having memory capacity being twice of the data block. Inverse reproduction having no discontinuity in sampling data unit can be realized without performing complex processing about writing/reading point and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital audio reproducing apparatus such as a CD player for reproducing a CD (compact disk) and an MD recorder having a function for reproducing an MD (mini disk), and a reproducing method.

[0002]

2. Description of the Related Art In a digital audio reproducing apparatus, each sampled data in digital audio data generated based on a reproduced signal reproduced from a recording medium is reproduced by reproducing the sampled data in the reverse order of the time lapse of the actual performance. It is well known that reproduction is possible.

For example, even in an MD recorder, reverse reproduction is possible by performing an array conversion process on digital audio data and arranging individual sampling data in a reverse order to the elapsed time of an actual performance. However, in an actual MD recorder, the generated digital audio data is
The data is output to the subsequent stage in units of a data block as an aggregate of a predetermined number of sampling data (see FIG. 5).

[0004] For this reason, only reverse order output in units of data blocks is possible. Such reproduction is hereinafter referred to as pseudo reverse reproduction. In the pseudo reverse reproduction, the sampling data array is arranged in the order of the actual playing time in each data block. Therefore, discontinuity occurs in the sampling data at the boundary between a certain data block M and the following data block M-1.

[0005] For this reason, the reproduced sound of the pseudo reverse reproduction is unnatural compared to the original reverse reproduction, that is, the reproduced sound generated by arranging the individual sampled data in the reverse order to the elapsed time of the actual performance. Problem. To cope with this problem, a configuration circuit having a function of converting a data array in each data block in the reverse order has been provided. As such a configuration, for example, a general-purpose DSP (Digital Singnal Procedure
ssor) etc. can be used.

However, in such a configuration, a counter for counting the number of sampling data corresponding to the block length of the data block, and a storage area for storing a memory address at the head of each data block where the sampling data is stored. Need to be managed. For this reason,
A problem arises in that processing for memory management becomes complicated and causes factors such as an increase in program capacity and a decrease in processing speed.

[0007]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to perform high-precision reverse reproduction without increasing the program capacity, reducing the processing speed, or the like, or minimizing the degree thereof. It is an object of the present invention to provide a reproducing apparatus and a reproducing method capable of performing the above.

[0008]

According to a first aspect of the present invention, there is provided a reproducing apparatus for reproducing digital audio information from a recording medium, wherein digital audio data is generated based on a reproduction signal reproduced from the recording medium. Digital audio data reproducing means for outputting the generated digital audio data to the subsequent stage in units of a predetermined number of data blocks as a set of sampling data, and block head data for specifying the head of the data block for the digital audio data A block head data specifying signal generating means for generating a specific signal; a ring buffer having twice the memory capacity of the data block; and a digital audio data writing / writing to the ring buffer with reference to the block head data specifying signal.
A reproduction apparatus comprising: data array conversion control means for converting the order of sampling data in a data block by controlling reading.

According to a seventh aspect of the present invention, in a reproducing method for reproducing digital audio information from a recording medium, digital audio data is generated based on a reproduction signal reproduced from the recording medium, and the generated digital audio data is converted to digital audio data. A digital audio data reproducing step of outputting to a subsequent stage a data block as a set of a predetermined number of sampling data; and generating a block head data specifying signal for specifying a head of the data block for the digital audio data. And controlling the writing / reading of digital audio data to / from the ring buffer having twice the memory capacity of the data block with reference to the block head data specifying signal, thereby changing the order of the sampling data in the data block. A reproduction method characterized by having a data array conversion step of conversion.

According to the invention described above, at the time of reverse reproduction,
The data array conversion processing can be accurately performed based only on the output timing of the sampling data at the head of the data block ascertained from the block head data timing signal. Then, high-precision reverse reproduction without discontinuity in sampling data units can be realized.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The overall structure of an embodiment of the present invention will be described below with reference to FIG. The audio data generation unit 21 performs decoding, error correction, and AT based on a reproduction signal reproduced from a recording medium such as an MD.
Processing such as RAC (Adaptive TRansform Acoustic Coding) decompression is performed to generate ATRAC decompressed data as reproduced digital audio data, and output it to the subsequent stage. The ATRAC decompressed data is a data block composed of a predetermined number of sampling data.
Further, the audio data generation unit 21 outputs a block head data output timing signal indicating the output timing of the data at the head of each data block to the subsequent stage. Further, the audio data generation unit 21 has a function of pseudo-reversely reproducing and outputting ATRAC decompressed data.

ATRAC is a compression method of digital audio data which has been relatively recently used in MD and the like, and is a modified DCT (Modified Discrete Cosine).
Transfer), and processing in consideration of human auditory characteristics. In one embodiment of the present invention, the compression ratio by ATRAC is about four times.
That is, when ATRAC decompression processing is performed on decoded data based on a reproduced signal reproduced from a recording medium, ATRAC decompressed data having a data amount about four times as large as the decoded data is obtained.

The recorded digital audio data before compression has a dynamic range, that is, an information amount per sample of 16 bits = 2 bytes. Then, 512 samples (thus 512 × 2 = 1024 bytes) are compressed to 212 bytes by ATRAC. These 212 bytes are called one sound group.
Furthermore, 5.5 sound groups make up one sector,
32 sectors constitute one cluster.

Then, one sector (that is, ATRAC
(1024 × 5.5 = 5632 bytes after decompression) is the minimum unit of data output from the audio data generation unit 21 in the MD recorder. Therefore, in the MD recorder, one data block corresponds to one sector.
In a CD player, one data block is one frame (consisting of 588 channel bits of data and corresponding to 1/75 second reproduced audio data).

In the subsequent stage of the audio data generator 21,
A storage circuit 23 including a data array conversion control unit 22 and a ring buffer 24 composed of, for example, a RAM (which will be described later) is provided. When the reverse playback mode is instructed, the audio data generation unit 2
1 performs pseudo reverse reproduction output, and controls the storage circuit 23 with reference to the audio data generation section 21 block head data output timing signal, thereby rearranging the sampling data in each data block in the reverse order. Output. In the embodiment of the present invention, a RAM or the like used as a buffer memory for the shock proof memory function is provided separately from the ring buffer 24 in the storage circuit 23.

The shock proof memory function is interrupted by a reproduced sound when a signal reading section such as an optical pickup is shifted from a correct reading position due to a vibration applied to the apparatus and the reproduced signal from the recording medium is interrupted ( This is a function of preventing occurrence of so-called sound skipping or reducing the possibility thereof. In order to realize this function, a buffer memory such as a RAM is provided, and the digital audio data supplied from the audio data generation unit 21 is temporarily stored in the buffer memory.
A configuration that is supplied to a subsequent processing circuit that performs D / A conversion or the like is used.

With such a configuration, even if the reproduction signal from the recording medium is interrupted and the generation of new digital audio data is interrupted, reproduced sound is generated based on the data stored in the buffer memory. Therefore, there is no interruption in the reproduced sound until the data in the buffer memory runs out. During this time, if the signal reading means such as the optical pickup is returned to the correct reading position and returned to the state where the reproduced signal can be read normally, the occurrence of sound skipping can be prevented.

When the reverse reproduction mode is instructed, the audio data generation section 21 performs pseudo reverse reproduction output, and the audio data generation section 21 will be described below with reference to a block top data output timing signal. By controlling the storage circuit 23 in this way, the sampling data in each data block is rearranged in the reverse order and output. The ring buffer memory 24 in the storage circuit 23 will be described with reference to FIG. Ring buffer memory 2
No. 4 has a capacity capable of storing twice the data amount of the data block. Data array conversion control unit 22
Controls the ring buffer memory 24, that is, sets a write point and a read point.

The control of the writing point is as follows. First, the write point of the sampling data at the head of the data block is set. Thereafter, by updating the write point in a certain direction, the subsequent sampling data is sequentially written. On the other hand, as described later, the read point is controlled so that the update direction is different between normal reproduction and reverse reproduction.

At the time of normal reproduction, the ring buffer memory 2
The read point 26 from 4 is set on the writing point 27 of the latest sampling data or on the writing point of the sampling data written several points before the latest data. That is, the update direction of the read point is the same as the update direction of the write point. In this way, the sampling data is read out in the order of the write points and output to the subsequent stage.

Next, the processing at the time of reverse reproduction will be specifically described with reference to FIG. Here, FIG. 3A illustrates setting of a writing point and a reading point with respect to the ring buffer memory 24. FIG. 3B shows the output of the audio data generation unit 21 in the reverse playback mode. FIGS. 3C and 3D show the writing of data blocks into two areas P and Q on the ring buffer memory 24, which will be described later. On the other hand, FIG.
2 shows the data after the array conversion read from the.

As described above, in the reverse reproduction mode, since the audio data generating section 21 performs pseudo reverse reproduction output, the ATRAC decompressed data is converted into data blocks M, M-1, M-2,... As shown in FIG. 3B. And output to the ring buffer 24. Here, inside each data block, the sampling data is arranged as 1, 2,... N in the order of sampling.

If the internal arrangement of each data block is kept in the order in which it was sampled, for example, at the next time point when the last (ie, n-th) sampled data in the data block M is output, one Previous data block M
The sampling data at the head of -1 is output. Therefore, a discontinuity occurs in the output sampling data unit at the boundary of the data block. If the subsequent processing is performed based on such an output, acoustically unnatural audio data is generated.

Therefore, in one embodiment of the present invention, as shown in FIG. 3A, at the time of reverse reproduction, the update direction of the read point is opposite to the update direction of the write point. For example, when the reverse playback mode starting from the data block M is instructed, a write point (in FIG. 3A, denoted by a symbol S in FIG. 3A) at which the first (ie, first) sampling data in the data block M is written. (Indicated by arrow 51) is set in the direction opposite to the update direction of the write point (indicated by arrow 50).

By such control of the ring buffer 24, in the period a in which the data block M is written, the sampling data in the data block M is 1, 2,. It is written in order. Here, the area P occupies half of the ring buffer 24. Then, as described above, the ring buffer 2
4 is twice as large as the data capacity of the data block, so that the data block M can be written on the area P without excess or deficiency.

In the period a, reading is performed from the area Q on the ring buffer 24 other than the area P (therefore, the area Q also has a data capacity of one data block). However, the data read out during the period a is, for example, data written when normal reproduction is performed before the time point when the reverse reproduction mode is instructed. Irrelevant. Therefore, the data read in the period a is not output to the subsequent stage (see FIG. 3E).

At the end of the period a, that is, when the writing of the data block M is completed, the writing point is located at the point T opposite to the point S.
At this point, the read point is located at point T. Therefore, the audio data generation unit 2 continues
The data block M-1 supplied by the pseudo reverse reproduction output by No. 1 is written in the area Q in the order of 1, 2,..., N (see FIG. 3D).

In the period in which data block M-1 is written in this manner (period b in FIG. 3), data block M written in period a is read from region P. At this time, the sampling data in the data block M is n, n−1.
1 (see FIG. 3E). In this way,
The output order of the sampling data in the data block M can be reversed from the sampling order.

Further, at the end of the period b, that is, when the writing of the data block M-1 is completed, the writing point is located at the point S. At this point, the read point is located at point T. That is, the state is the same as when the writing of the data block M is started. Then, subsequently, the data block M-2 supplied by the pseudo reverse reproduction output by the audio data generation unit 21 is written in the area P in the order of 1, 2,..., N (see FIG. 3C).

In the period in which data block M-2 is written (period c in FIG. 3), data block M-1 written in period b is read from region Q. At this time, the sampling data in the data block M-1 is n, n-1.
.. Are read in the order of 2, 1 (see FIG. 3E). In this manner, the output order of the sampling data in the data block M-1 can be reversed from the sampling order.

In the same manner, all the sampling data are sampled by sequentially writing and reading the data blocks supplied by the pseudo reverse reproduction output by the audio data generation unit 21 in the ring buffer 24. Order
Can be output in reverse.

Hereinafter, as a more specific configuration example, an MD recorder to which the present invention is applied will be described with reference to FIG. Here, the data read block 11 and the ATR
The AC decompression block 12 is included in the audio data generation unit 21 in FIG. However, the block head data timing signal Bf is generated by the control microcomputer 14 as described later. The data array conversion block 13
The data array conversion control unit 22 and the ring buffer 2 in FIG.
4 is included.

The data read block 11 causes MD1
The data reproduced from 0 is the ATRAC decompression block 12.
Supplied to The ATRAC decompression block 12 performs ATRAC decompression processing on the supplied data, generates ATRAC decompressed data, and supplies it to the data array conversion block 13. The data read block 11 and the ATRAC decompression block 12 can perform both 1 × speed reproduction and 2 × speed reproduction.

The control microcomputer 14, which controls the operation of the entire apparatus, comprises a data read block 11 and an ATRA
A block head data timing signal Bf is generated according to the state of data processing in the C decompression block 12, and the block head data timing signal Bf is supplied to the data array conversion block 13. The data transfer rate of ATRAC decompressed data is, for example, 44.1 according to a data transfer clock generated by a PLL circuit or the like (not shown).
It is fixed at a rate corresponding to 88.2 kHz, which is twice the kHz.

The data array conversion block 13 performs processing for the shock proof function, and at the time of reverse reproduction, samples in each data block of ATRAC decompressed data supplied with reference to the block head data timing signal Bf. Transform the order of Thus, at the time of reverse reproduction, the sample order is continued even at the boundary of the data block.

The output of the data array conversion block 13 is D /
The signal is supplied to the A conversion block 14. The D / A conversion block 14 converts the supplied digital audio data into a D / A signal.
A conversion is performed to convert to an analog signal. The analog signal drives a sound generator such as a headphone speaker, and outputs sound.

In the embodiment of the present invention described above, a ring buffer 24 used for performing data array conversion, a RAM used as a buffer memory for performing a shock proof memory function, and the like are separately provided. ing. One rewritable memory is provided in the storage circuit 23, and the memory is used exclusively as a buffer memory for performing a shock-proof memory function during normal reproduction, and a part of the memory is used as a ring buffer 24 during reverse reproduction. You may make it do. In such a configuration, the control of the memory in the storage circuit 23 is complicated, but the total amount of the memory in the storage circuit 23 can be reduced.

One embodiment of the present invention described above is an application of the present invention to an MD recorder. The present invention relates to data reproduced in the reverse order of the sampling order using a predetermined amount of data such as a data block as a unit. If the playback device has a playback processing system having a function of outputting data, it can be applied to a case where a device other than the MD is used as a configuration for supplying data to be played back to the playback system, such as a recording medium or a communication line. .

That is, in addition to the MD, for example, a magneto-optical disk (MO), a phase-change disk PD, a CD-E (CD
-Erasable), write-once disks such as CD-Rs, read-only disks such as CDs, CD-ROMs and DVDs, and digital audio reproducing apparatuses using magnetic disks. further,
The present invention is also applicable to a case where a tape-shaped recording medium such as a magnetic tape or an optical tape or a semiconductor memory is used as a recording medium. The present invention can also be applied to a case where data to be reproduced is supplied from a content server or the like to a reproduction system via a network using a telephone line or the like.

Particularly, a low-cost, high-quality reverse reproduction is performed, for example, by using a digital device to realize the same or similar function as an analog device, or by using a jog dial or the like to search for an editing point. It is effective to apply the present invention to a device that requires a function. In addition, for example, in the entire signal processing including the reproduction of video data and the like, it is effective to apply the present invention to realize a function of rearranging and outputting data strings in a specific range in reverse.

The present invention is not limited to the above-described embodiment, and various applications and modifications can be made without departing from the gist of the present invention.

[0042]

As described above, according to the present invention, in a reproducing apparatus for reproducing digital audio information from a recording medium, pseudo reverse reproduction output using a predetermined amount of data such as a data block as an output unit is provided. In addition, the pseudo reverse reproduction output is processed by using a ring buffer having twice the memory capacity of the data block by referring to a block head data timing signal indicating the output timing of the head of the data block. A data array conversion process for converting the order of sampling data in each data block is performed.

With such a configuration, at the time when reading of the sampling data for a certain data block M from the half area of the ring buffer in the reverse order is completed at the time of the reverse reproduction, the subsequent data block M-1 is placed in the ring buffer. It is made to be written in the other half area. Therefore, immediately after the reading of the data block M in the reverse order is completed, the reading of the data block M-1 in the reverse order can be started. For this reason,
It is possible to realize high-precision reverse reproduction without discontinuity in units of sampling data without performing special processing such as jump processing of a read point / write point.

Therefore, the data array conversion processing can be properly performed based only on the output timing of the sampling data at the head of the data block ascertained from the block head data timing signal. For this reason, for example, D
This eliminates the need to perform the process of counting the number of sampling data, the process of storing the storage address of the sampling data at the head of the block, and the like, which were performed in the conventional data array conversion process using SP or the like. .

Therefore, the data array conversion process can be simplified, and the program capacity and the processing time for performing the data array conversion process can be reduced. Therefore, it is possible to contribute to miniaturization and cost reduction of the overall configuration of the device.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining an overall configuration of an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a ring buffer according to an embodiment of the present invention.

FIG. 3 is a schematic diagram illustrating a data array conversion process.

FIG. 4 is a block diagram for explaining an example of a more specific configuration of an embodiment of the present invention.

FIG. 5 shows output of digital audio data.
FIG. 3 is a schematic diagram illustrating a data block and a sampling block.

[Explanation of symbols]

21: audio data generation unit, 23: data array conversion control unit, 23: storage circuit, 24: ring buffer

Claims (7)

[Claims] 1. A reproducing apparatus for reproducing digital audio information from a recording medium, wherein digital audio data is generated based on a reproduction signal reproduced from the recording medium, and the generated digital audio data is converted into sampling data. Digital audio data reproducing means for outputting the data block as a unit in units of a predetermined number of data blocks to a subsequent stage; and for the digital audio data, a block head data specifying signal for generating a block head data specifying signal for specifying a head of the data block. A signal generating unit; a ring buffer having a memory capacity twice as large as the data block; and a control of writing / reading of the digital audio data to / from the ring buffer with reference to the block head data specifying signal. Ri, reproducing apparatus characterized by having a data array conversion control means for converting the order of the sampling data in the data block. 2. The reproducing apparatus according to claim 1, wherein the block head data specifying signal is a microcomputer that controls the operation of the entire apparatus. 3. The device according to claim 2, wherein the microcomputer that controls the operation of the entire device generates the block head data specifying signal in accordance with a data output performed by the digital audio data reproducing unit. Playback device. 4. The reproducing apparatus according to claim 1, wherein the block head data specifying signal indicates a timing at which the head sampling data of the data block is supplied to the data array conversion control means. 5. The data array conversion control means according to claim 1, wherein the writing point and the reading point are sequentially updated with respect to the ring buffer in accordance with a timing at which each sampling data in the digital audio data is supplied. A reproducing apparatus characterized by the above-mentioned. 6. The reproducing apparatus according to claim 5, wherein an update direction of the read point is made opposite to an update direction of the write point during reverse reproduction. 7. A reproducing method for reproducing digital audio information from a recording medium, comprising the steps of: generating digital audio data based on a reproduction signal reproduced from the recording medium; A digital audio data reproducing step of outputting a data block as a unit of a predetermined number as a unit to a subsequent stage, and a step of generating a block head data specifying signal for specifying a head of the data block for the digital audio data; By controlling the writing / reading of the digital audio data to / from the ring buffer having twice the memory capacity of the data block with reference to the block head data specifying signal, the order of the sampling data in the data block is controlled. A data array conversion step of converting the order.