JP3799205B2 - Data recording / reproducing apparatus and data recording / reproducing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a data recording / reproducing apparatus and a data recording / reproducing method. For example, in an audio and / or video server system having a disk-shaped recording medium as a recording medium, an information signal is reproduced from a recording medium of a media unit and distributed to a terminal device. Therefore, the present invention is suitable for application to a system.
[0002]
[Prior art]
An audio / video server system (hereinafter referred to as an AV server system) has been proposed as a device for supplying video signals and audio signals to a plurality of terminal devices from a single video / audio supply source provided in a broadcasting station or the like. . As a configuration of this AV server system, a configuration is proposed in which video and audio signals are stored in a media unit incorporating a plurality of disk devices, and the selected video and audio signals are distributed from the media unit to a terminal device. Has been.
[0003]
[Problems to be solved by the invention]
By the way, in such an AV server system, it is necessary to transmit a video signal to each terminal device without interruption. For this reason, the media unit of the AV server system reproduces video and audio signals from the disc-shaped recording medium in the disc device so that a video signal having a fixed amount of data can be always supplied to each terminal device.
[0004]
Here, a disk device for reproducing video and audio signals from a disk-shaped recording medium will be described. Here, a case where a hard disk device is used as the disk device will be described.
[0005]
The hard disk device is configured to rotate a hard disk, which is a disk-shaped magnetic recording medium, and to record video and audio signals on the hard disk by a recording / reproducing head and to reproduce from the hard disk. At this time, since there is generally one recording / reproducing head, access to video and audio signals on the hard disk by this recording / reproducing head is performed sequentially.
[0006]
Further, since the recording / reproducing head operates mechanically, the access time is changed when the access position of the recording / reproducing head is significantly changed, that is, when the so-called seek is performed, as compared with the case where the continuous position is accessed by the recording / reproducing head. It takes a long time. Further, even after the recording / reproducing head is moved, a certain time is required until the recording position of the selected video and audio signal reaches the position of the recording / reproducing head. This is called rotation waiting time.
[0007]
Here, like the disk device used in the AV server system described above, when it is necessary to always supply a video and audio signal of a certain amount of data to each terminal device, seek, wait for rotation, and data output. In consideration of the total access time included, the ability to output video and audio signals continuously is required.
[0008]
In the AV server system, the data read from the hard disk is video and audio signals, so real-time performance is required. For example, unless a playback video and audio signal of 128 [kByte] per second is continuously supplied to one terminal device, the video is interrupted. Therefore, to supply video and audio signals to 12 terminal devices without interruption, assuming that the number of transmission channels is 12, video and audio of 128 [kByte] * 12 [channels] = 1536 [kByte] per second. The signal needs to be played back from the hard disk.
[0009]
Further, since the hard disk device operates mechanically, the frequency of occurrence is low, but in some cases, an unexpected operation may occur. For example, when accessing a video and audio signal by moving the head on a predetermined circumference of the hard disk, the position of the recording / reproducing head is shifted due to expansion and contraction due to the temperature of each member or mechanical error, and the video and audio signal May not be read correctly. In this case, the hard disk device corrects the position of the recording / reproducing head and accesses again. Normally, correct video and audio signals can be read while repeating this access operation.
[0010]
However, when such an operation is performed, the rotation waiting time becomes particularly long, and the access speed decreases. For this reason, when reproducing data is supplied to each channel, a predetermined amount of data that must be read within one second, more specifically within 950 [milliseconds] in consideration of the overhead time in the control system. If a video and audio signal block is played back in 1.3 [seconds], for example, the next video and audio signal block cannot be played back in time, and the video and audio signal supplied to the terminal device is interrupted. There is a point.
[0011]
The present invention has been made in consideration of the above points, and an object of the present invention is to provide a data recording / reproducing apparatus and a data recording / reproducing method capable of supplying video signals to a plurality of channels without interruption.
[0012]
[Means for Solving the Problems]
In order to solve such a problem, in the present invention, a plurality of disk devices for recording and reproducing data including video and audio data, a plurality of input / output means connected to the plurality of disk devices, and the data in block units in order. When a plurality of input / output means inputs data to a plurality of disk devices, and a certain disk device outputs data exceeding the first period when reading data corresponding to the first period, the first period The input / output means is controlled so that the data corresponding to the third period following the second period is read from the beginning of the third period without reading the data corresponding to the second period following the second period. And control means to provide.
[0013]
Further, in the present invention, a first step of recording data including video and audio data in order on a block basis on a plurality of disk devices, and a second step of reading data recorded at the first step from the plurality of disk devices. In the second step, when data corresponding to the first period is read, when data is read from a disk device that exceeds the first period, The data corresponding to the second period is not read, and the data corresponding to the third period subsequent to the second period is read from the beginning of the third period.
[0014]
When data corresponding to the first period is read out, the data corresponding to the second period following the first period is not read when the data is read from the disk device beyond the first period. The data corresponding to the third period subsequent to the second period is read from the beginning of the third period, and the skipped data is error-corrected from the data of the preceding and succeeding blocks and output. As a result, real-time performance can be ensured without delaying the supply of data.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the data recording / reproducing apparatus of the present invention will be described with reference to FIGS.
[0016]
First, an embodiment of an audio / video server system (hereinafter referred to as an AV server system) 20 to which the data recording / reproducing apparatus of the present invention is applied will be described with reference to FIG. Video and audio data D20 output from a data supply source 22 composed of a video tape recorder 21 with a playback function is supplied to the encoder 24 of the encoding unit 23.
[0017]
The encoder 24 compresses and encodes the supplied video and audio data D20 using, for example, a compression algorithm according to the MPEG2 standard, thereby forming encoded video and audio data D21. The encoded video and audio data D21 encoded by the encoder 24 is supplied to the server unit 25.
[0018]
The server unit 25 includes a media control unit 26 and a plurality of media units 27A1 to 27A7. Then, the encoded video and audio data D21 encoded by the encoder 24 are supplied to the media control unit 26. Each of the media units 27A1 to 27A7 includes a plurality of hard disk devices.
[0019]
The media control unit 26 of the server unit 25 responds to the write control signal supplied from the control unit 28 via the control line S1 to the input encoded video and audio data D21 in the media units 27A1 to 27A7. Supply to any media unit. In addition, the media control unit 26 drives the hard disk devices in the media units 27A1 to 27A7 in accordance with the reproduction control signal supplied from the control device 29 via the control line S2, and performs desired encoded video and audio from the hard disk. Play the data.
[0020]
The media control unit 26 has a built-in decoder unit 35 (FIG. 2), and decodes encoded video and audio data reproduced by the hard disk device. Further, the media control unit 26 has a data distribution function, and the video and audio data D22 decoded by the error code decoder 34 and the decoder unit 35 is transmitted according to the distribution control signal supplied from the control device 29 via the control line S2. For example, it supplies selectively to terminal device 28A1-28A12 which has a television receiver.
[0021]
In the AV server system 20, the encoding operation of the encoder 24 and the reproduction operation of the data supply source 22 are controlled by control signals supplied from the control unit 28 via control lines S3 and S4, respectively. Further, the control unit 28 monitors the operation state of the encoder 24 and the operation state of the data supply source 22 based on operation state notification signals supplied via the control lines S3 and S4, respectively. Further, the control unit 28 monitors the operation state of the media control unit 26 based on an operation state notification signal supplied via the control line S1. Furthermore, control such as operation start and operation end for the control unit 28 is performed by the control device 29 via the control line S5.
[0022]
Next, the configuration of the server unit 25 will be described with reference to FIG. In order to simplify the description, the encoded video and audio data are recorded on the hard disk device group in the media unit 27A1 among the media units 27A1 to 27A7 shown in FIG. An example in which encoded video and audio data are reproduced from will be described.
[0023]
First, the operation when the encoded video and audio data D21 supplied from the encoder 24 shown in FIG. 1 is recorded on the hard disk by the hard disk devices 271 to 276 in the media unit 27A1 in the server unit 25 will be described.
[0024]
The encoded video and audio data D21 output from the encoder 24 is supplied to the error code encoder 31 via the encoder interface 30. The error code encoder 31 divides the encoded video and audio data D21 into a predetermined amount of data, for example, every 5 bytes, and sequentially inputs / outputs each 1-byte data block formed by dividing into 5 via the signal line S22. Supply to parts 32A, 32B and 32C.
[0025]
For example, the first data block and the second data block of each 1-byte data block divided into five are supplied to the input / output unit 32A, and the third data block and the fourth data block are input to the input / output unit 32B. And the fifth data block is supplied to the input / output unit 32C. Further, the error code encoder 31 generates an error correction code from the five divided data and supplies it to the input / output unit 32C. As this error correction code, for example, an XOR code is used.
[0026]
The main CPU 33 of the media control unit 26 is supplied with a write control signal from the control unit 28 via the control line S1, and in response to the control signal, the hard disk devices 271 to 276 send encoded video and audio signals and error correction codes. Is supplied to the input / output units 32A to 32C via the control line S6.
[0027]
Here, the configuration of the input / output units 32A to 32C will be described with reference to FIG. Since the input / output units 32A to 32C have the same configuration, only the configuration of the input / output unit 32A is shown in FIG.
[0028]
A control signal supplied from the main CPU 33 via the control line S6 is supplied to the CPU 44. Further, the first data block and the second data block described above from the error code encoder 31 are respectively supplied to the buffer memories 40 and 41 having a double buffer configuration via the signal line S22.
[0029]
When the control signal is supplied via the control line S6, the CPU 44 supplies the read data signal via the control line S11 to supply the head data block stored in the buffer memory 40 to the hard disk device 271 and performs control. A control signal is sent to the interfaces 42 and 43 via the control line S8 so that the second data block stored in the buffer memory 41 is supplied to the hard disk device 272 by giving a read signal via the line S12. Supply.
[0030]
As a result, the interface 42 reads the head data block described above from the buffer memory 40, supplies it to the hard disk device 271, and causes the hard disk device 271 to record it on the hard disk. Further, the interface 43 reads the second data block described above from the buffer memory 41, supplies it to the hard disk device 272, and causes the hard disk device 272 to record it on the hard disk.
[0031]
Note that the configuration and operation of the input / output unit 32B at the time of recording are the same except that the first data block and the second data block described above are replaced by the third and fourth data blocks, respectively. The configuration and operation of the unit 32A are the same. The configuration and operation of the input / output unit 32C at the time of recording is the same as that of the input / output unit except that the first data block and the second data block described above are replaced with the fifth data block and the error correction code data, respectively. The configuration and operation of the unit 32A are the same.
[0032]
In this way, the input / output units 32A to 32C can record the encoded video and audio data supplied from the error code encoder 31 in the hard disk devices 271 to 275, and the error correction code data to the hard disk device 276. Can be recorded. As a result, the hard disk devices 271 to 275 function as a hard disk device for recording and reproducing encoded video and audio data, and the hard disk device 276 functions as a hard disk device for recording and reproducing error correction code data.
[0033]
FIG. 4A shows the positional relationship of each data block and error correction code data on each hard disk when each data block and error correction code data is recorded on each hard disk in each of the hard disk devices 271 to 276 as described above. ) To FIG. 4 (F).
[0034]
First, the arrangement of each data block when encoded video and audio data are recorded on the hard disk in the hard disk device 271 will be described with reference to FIG. The encoded video and audio data are divided into a predetermined amount of data, for example, every 5 bytes, and the first data block of each 1-byte data block divided into 5 is supplied to the hard disk device 271 and continuously on an empty track of the hard disk. And recorded.
[0035]
Therefore, if each divided data block is assigned a serial number to identify each block, the hard disk in the hard disk device 271 has data blocks 1, 6, 11, 16, as shown in FIG. 21, 26, 31... Are recorded continuously. These data blocks 1, 6, 11, 16, 21, 26, 31... Are all data blocks at the head of each 1-byte data block divided into five.
[0036]
Further, as shown in FIG. 4B, data blocks 2, 7, 12, 17, 22, 27, 32,... Are continuously recorded on the hard disk in the hard disk device 272. These data blocks 2, 7, 12, 17, 22, 27, 32... Are the second data block of each 1-byte data block divided into five.
[0037]
Further, as shown in FIG. 4C, data blocks 3, 8, 13, 18, 23, 28, 33,... Are continuously recorded on the hard disk in the hard disk device 273. These data blocks 3, 8, 13, 18, 23, 28, 33... Are all third data blocks of 1-byte data blocks divided into five.
[0038]
Further, as shown in FIG. 4D, data blocks 4, 9, 14, 19, 24, 29, 34,... Are continuously recorded on the hard disk in the hard disk device 274. These data blocks 4, 9, 14, 19, 24, 29, 34... Are all the fourth data blocks of 1-byte data blocks divided into five.
[0039]
Further, as shown in FIG. 4E, data blocks 5, 10, 15, 20, 25, 30, 35... Are continuously recorded on the hard disk in the hard disk device 275. These data blocks 5, 10, 15, 20, 25, 30, 35... Are the fifth data block of each 1-byte data block divided into five.
[0040]
In addition, as shown in FIG. 4F, the hard disk in the hard disk device 276 has error correction code data P1 and data blocks 6, 7 generated for the data blocks 1, 2, 3, 4, 5, as shown in FIG. , 8, 9, 10 error correction code data P2 generated, data blocks 11, 12, 13, 14, 15 error correction code data P3 generated, data blocks 16, 17, 18, 19 , 20 for the error correction code data P4 generated for the data blocks 21, 22, 23, 24, 25, and the data blocks 26, 27, 28, 29, 30 generated for the data blocks 21, 22, 23, 24, 25 The error correction code data P6 generated and the error correction code data P7... Generated for the data blocks 31, 32, 33, 34, and 35 are continuously recorded. It is.
[0041]
Next, a recording format to the hard disk in each of the hard disk devices 271 to 276 shown in FIG. 2 will be described with reference to FIG. The hard disk is assigned the next area from the outer periphery to the inner periphery. ID area in which identification data for the format method is recorded, format area in which data on the recording start sector address and size of each information data recorded on the hard disk is recorded, and encoded video And an information data area in which audio data is recorded, and a control data area in which clip management data, which is management information on discs and encoded video and audio data, is recorded.
[0042]
Further, this control data area is divided into the following areas. System information area where clip information registration information data is recorded, file information area where each clip information data is recorded, encoded video and audio data, and recording position of error correction code data on the hard disk in cluster units Divided into a file allocation table area in which data for management is recorded. The reserved area is an area reserved for expansion.
[0043]
FIG. 6 shows an example of the number of sectors allocated to each area when the recording format of a hard disk with a capacity of 2.15 [Gbyte], for example, is selected as shown in FIG.
[0044]
Next, operations when the encoded video and audio data are reproduced from the hard disk devices 271 to 276 shown in FIG. 2 and the decoded video and audio data are supplied to each terminal device will be described.
[0045]
Each terminal device 28A1 to 28A12 shown in FIG. 1 transmits request data for video and audio data to be received to the control device 29 via the communication line S20. The control device 29 supplies a reproduction control signal for distributing the video and audio data requested from each terminal device to each terminal device to the media control unit 26 in the server unit 25 via the control line S2. The reproduction control signal supplied to the media control unit 26 is supplied to the main CPU 33 (FIG. 2) in the media control unit 26. Based on this reproduction control signal, the main CPU 33 sends a control signal for reproducing the requested video and audio data and error correction code data from each hard disk via the control line S6 to the CPU 44 in the input / output units 32A to 32C. (FIG. 3).
[0046]
The input / output units 32A to 32C reproduce the requested video and audio data and error correction code data from each hard disk based on the reproduction control signal supplied from the main CPU 33. Here, in order to simplify the description, the reproduction operation of the input / output unit 32A will be described with reference to FIG.
[0047]
First, the CPU 44 manages the recording position of the encoded video and audio data and error correction code data on the hard disk in cluster units, and the address of the recording start sector of each information data recorded on the hard disk. Data about the size of each information data is read from each hard disk via the interface 42 or 43 and stored in the FAT memory 47.
[0048]
Next, the CPU 44 obtains the recording position of the requested encoded video and audio data and error correction code data on the hard disk with reference to the data stored in the FAT memory 47, and the encoded video is determined from the recording position. In addition, control signals are supplied to the interfaces 42 and 43 via the control line S8 so that the audio data and the error correction code data are reproduced.
[0049]
The interfaces 42 and 43 control the operations of the hard disk devices 271 and 272 based on a control signal from the CPU 44 so that the requested encoded video and audio data are read from the hard disk, respectively. Thus, for example, when the encoded video and audio data and the error correction code data requested this time are those shown in FIGS. 4A to 4F, the hard disk device 271 is shown in FIG. The data blocks 1, 6, 11, 16, 21, 26, 31... Are continuously reproduced, and the hard disk device 272 performs data blocks 2, 7, 12, 17, 22, 27 shown in FIG. , 32...
[0050]
The data blocks 1, 6, 11, 16, 21, 26, 31... And the data blocks 2, 7, 12, 17, 22, 27, 32. The data is supplied to the buffer memory 41, temporarily stored, and then supplied to the error code decoder 34 in the media control unit shown in FIG. 2 via the signal line S30.
[0051]
Reading of data from the buffer memory 40 and the buffer memory 41 is performed based on a control signal supplied from the CPU 44 via the control line S11 or the control line S12. Alternatively, data reading from the buffer memory 40 and the buffer memory 41 is performed based on a read control signal supplied from the error code decoder 34 to the buffer memories 40 and 41, although not shown.
Similarly, the hard disk device 273 continuously reproduces the data blocks 3, 8, 13, 18, 23, 28, 33... Shown in FIG. 4C under the control of the input / output unit 32B. . The hard disk device 274 continuously reproduces the data blocks 4, 9, 14, 19, 24, 29, 34,... Shown in FIG. 4D under the control of the input / output unit 32B.
[0052]
Further, the hard disk device 275 continuously reproduces the data blocks 5, 10, 15, 20, 25, 30, 35... Shown in FIG. 4E under the control of the input / output unit 32C. Further, the hard disk device 276 continuously reproduces the error correction code data P1, P2, P3, P4, P5, P6, P7,... Shown in FIG. To do.
[0053]
Data blocks 3, 8, 13, 18, 23, 28, 33..., 4, 9, 14, 19, 24, 29, 34. , 20, 25, 30, 35... And error correction code data P1, P2, P3, P4, P5, P6, P7,... Are once stored in one (or the other) of the buffer memories. Later, it is supplied to the error code decoder 34 in the media control unit shown in FIG.
[0054]
The error code decoder 34 performs error correction processing on the data blocks 1, 2, 3, 4, 5 supplied from the input / output units 32A to 32C using the error correction code data P1. The error code decoder 34 performs error correction processing on the data blocks 6, 7, 8, 9, 10 supplied from the input / output units 32A to 32C using the error correction code data P2. The error code decoder 34 performs error correction processing on the data blocks 11, 12, 13, 14, 15 using the error correction code data P3. The error code decoder 34 performs error correction processing on the data blocks 16, 17, 18, 19, and 20 using the error correction code data P4.
[0055]
The error code decoder 34 performs error correction processing on the data blocks 21, 22, 23, 24, 25 using the error correction code data P5. The error code decoder 34 performs error correction processing on the data blocks 26, 27, 28, 29, and 30 using the error correction code data P6. The error code decoder 34 performs error correction processing using the error correction code data P7 generated for the data blocks 31, 32, 33, 34, and 35.
[0056]
The error code decoder 34 outputs the data blocks that have been subjected to the error correction process in the order of the block numbers, and based on the instruction signal indicating the transmission destination supplied from the main CPU 33 via the control line S9. The data is supplied to a designated decoder among the decoders 35A to 35L.
[0057]
Here, the error correction code described above has the ability to restore each data of the remaining one data block from the data of four data blocks of the five data blocks. Therefore, even if any one of the hard disk devices 271 to 276 does not perform a normal reproduction operation for some reason, the data of the data blocks supplied from the other four hard disk devices and the hard disk device 276 With the error correction code data to be reproduced, the data to be reproduced from the hard disk device that has stopped reproducing can be restored in the error code decoder 34.
By the way, for example, the terminal device 28A1 transmits a reception request for video and audio data A to the control device 29, and the terminal device 28A2 transmits a reception request for video and audio data B different from the video and audio data A to the control device 29. Then, the playback operation of the server unit 25 will be described in the case where the terminal device 28A3 transmits a reception request for video and audio data C different from the video and audio data A and B to the control device 29.
[0058]
The terminal device 28A1, the terminal device 28A2, and the terminal device 28A3 respectively send request data for video and audio data A, video and audio data B, and video and audio data C to be received to the control device 29 via the communication line S20. Send. The control device 29 receives the video and audio data A, the video and audio data B, and the video and audio data C requested from the terminal device 28A1, the terminal device 28A2, and the terminal device 28A3, respectively. Then, a reproduction control signal for distribution to the terminal device 28A3 is supplied to the media control unit 26 in the server unit 25 via the control line S2.
[0059]
The reproduction control signal supplied to the media control unit 26 is supplied to the main CPU 33 in the media control unit 26. Based on this reproduction control signal, the main CPU 33 sends a control signal for reproducing the requested video and audio data A, B and C and error correction code data of these data from each hard disk via the control line S6. To the CPU 44 in the input / output units 32A to 32C.
[0060]
As shown in FIG. 3, the CPU 44 records on the hard disk data and data for managing each recording position of the encoded video and audio data and error correction code data on the hard disk in units of clusters. Data about the address of the recording start sector of each information data and the size of each information data are read from each hard disk and stored in the FAT memory 47.
[0061]
Next, the CPU 44 obtains the recording position of each requested encoded video and audio data and error correction code data on the hard disk by referring to the data stored in the FAT memory 47, and from this recording position, each code Control signals are supplied to the interfaces 42 and 43 via the control line S8 so that the converted video and audio data and the error correction code data are reproduced.
[0062]
The interfaces 42 and 43 are based on a control signal supplied from the CPU 44 via the control line S8 so that each requested encoded video and audio data and error correction code data are read from the hard disk. The operation of 276 is controlled. As a result, each encoded video and audio data and error correction code data read from the hard disk devices 271 to 276 are supplied to one (or the other) of the buffer memory 40 and the buffer memory 41 in a time-sharing manner. After being stored, it is supplied in a time division manner to the error code decoder 34 in the media control unit shown in FIG.
[0063]
The error code decoder 34 performs error correction processing on each encoded video and audio data supplied from the input / output units 32A to 32C using error correction code data. The error code decoder 34 outputs each data block subjected to the error correction processing in this way in the order of the block number for each type of encoded video and audio data, and also indicates the transmission destination supplied from the main CPU 33 Based on the signal, the encoded video and audio data A are supplied to the decoder 35A, the encoded video and audio data B are supplied to the decoder 35B, and the encoded video and audio data C are supplied to the decoder 35C.
[0064]
Each of the decoders 35A, 35B, and 35C performs decoding and decompression processing on the supplied encoded video and audio data, respectively, and the continuous real-time video and audio data are respectively the terminal device 28A1, the terminal device 28A2, and the terminal. Delivered to the device 28A3.
[0065]
Each encoded video and audio data and error correction code data read from the hard disk devices 271 to 276 are supplied to one (or the other) of the buffer memory 40 and the buffer memory 41 in a time division manner and temporarily stored. Later, the error code decoder 34 in the media control unit 26 shown in FIG. 2 is supplied in a time-sharing manner, and after error correction processing is performed in the error code decoder 34, it is distributed to the decoders 35A, 35B and 35C. Since each encoded video and audio data is subjected to decoding and decompression processing in the decoders 35A, 35B and 35C, here, continuous real-time video and audio data are obtained.
[0066]
The encoded video and audio data A, the encoded video and audio data B, and the encoded video and audio data C are recorded in a mixed manner on the hard disk. Therefore, when reproducing these encoded video and audio data A, B and C from the hard disk, in order to minimize the movement of the recording / reproducing head of the hard disk device and shorten the access time, for example, this recording It is desirable to select the playback order of the encoded video and audio data A, B, and C so that the playback head moves regularly from the outer peripheral side to the inner peripheral side of the hard disk.
[0067]
In order to select this reproduction order, a sorting circuit 45 shown in FIG. 3 is used. The CPU 44 obtains the recording position of each requested encoded video and audio data and error correction code data on the hard disk with reference to the data stored in the FAT memory 47, and sorts the data indicating the recording position. 45. The sorting circuit 45 rearranges the data indicating the recording position, for example, from data indicating the position on the outer peripheral side of the hard disk to data indicating the position on the inner peripheral side, and supplies the data to the CPU 44.
[0068]
The CPU 44 supplies a control signal to the interfaces 42 and 43 via the control line S8 so that each encoded video and audio data and error correction code data are reproduced according to the rearranged data. Thereby, the recording / reproducing head can reproduce the encoded video and audio data and the error correction code data A, B, and C while moving regularly from the outer peripheral side to the inner peripheral side of the hard disk.
[0069]
Further, in the server unit 25 of the present embodiment, as described below, the supply of encoded video and audio data from the hard disk device to the decoder unit 35 can be performed without delaying more than a predetermined period. ing.
[0070]
When there is a read request for video and audio data from each of the terminal devices 28A1 to 28A12, the server unit 25 collects a predetermined number of data blocks, for example, 128000 * 12/5 = 307200 blocks as one read block and reads them from each hard disk. . The 307200 data blocks are read from each hard disk by each hard disk device within one second, whereby different video and audio signals can be continuously supplied to 12 terminal devices. The reproduction capability of each hard disk device is set so that the time required to read the 307200 data block from the hard disk is usually within 950 [milliseconds].
[0071]
At this time, the CPU 44 of each of the input / output units 32A, 32B, and 32C reads the data of the reproduction block (n) (n is a positive integer) currently reproduced from the hard disk by the hard disk device within a predetermined time, for example, It is indirectly determined by determining whether or not the playback of the next playback block (n + 1) is started at a designated timing, for example, 2 [seconds] after the start of playback. Monitor.
[0072]
In FIG. 7A to FIG. 7C, each region R indicated by hatching is an allowance time, and this time corresponds to the overhead time required for playback block switching control. In this embodiment, it is 50 [milliseconds]. Therefore, if playback of the playback block (n) takes 950 [milliseconds] or longer, the playback block (n + 1) cannot start playback from a predetermined timing.
[0073]
The reading operation of each reproduction block from the hard disk when the reading of this data is completed within a predetermined time, for example, within 950 [milliseconds] will be described with reference to FIG. In this case, reading of all the reproduction blocks n, n + 1, n + 2, n + 3... Is completed within 950 [milliseconds], and therefore all the reproduction blocks n, n + 1, n + 2, n + 3. It is played from the hard disk by the device. Each reproduction block shown in FIG. 7A is composed of 307200 data blocks shown in FIG.
[0074]
Next, for example, when accessing the encoded video and audio data by moving the head on the circumference where the reproduction block n of the hard disk is recorded, the recording / reproduction is performed due to expansion / contraction due to the temperature of each member or mechanical error. The head position is shifted, the encoded video and audio data of the playback block n cannot be read correctly, the recording / playback head position is corrected, and the operation is performed again. For example, playback takes 1.3 [seconds]. When the reproduction of block n is completed, the reading operation of each reproduction block from the hard disk will be described with reference to FIG.
[0075]
In this case, since reading of the reproduction block n takes 1.3 [seconds], the next reproduction block n + 1 of the reproduction block n is at a timing delayed by 0.3 [seconds] from the designated read timing. Reading starts. Therefore, the reading end timing of the reproduction block n + 1 is also designated, for example, 2 [seconds] from the start of the reproduction operation, and as a result, the reproduction timing of the reproduction block n + 2 is also designated, for example, The time of 2 [seconds] has passed since the start of the reproduction operation. Similarly, this delay in timing adversely affects the playback timing of several subsequent playback blocks.
[0076]
This delay in timing may make it impossible to supply continuous video and audio data to the terminal device. In other words, due to this timing delay, the encoded video and audio data reproduced from this hard disk are not subject to decoding. Therefore, the encoded video and audio data of the reproduction blocks reproduced from the other four hard disks, respectively. Thus, since the error correction code data is restored and supplied to the terminal device, the video and audio data are not directly interrupted. If an error occurs in the encoded video and audio data in any one of the reproduction blocks, the encoded video and audio data cannot be restored, and the video and audio data are interrupted.
[0077]
As described above, if there is no delay in the reproduction timing, the encoded video and audio data are invalidated only by the fact that the reproduction timing is delayed although the reproduction is performed as valid encoded video and audio data. Therefore, this delay increases the possibility of interrupting the video and audio data supplied to the terminal device. That is, the correction capability of the error correction code used in this embodiment is such that even if one of the five data blocks is missing, the data of the missing data block is restored from the remaining four data blocks. If one data block is always invalid over a period corresponding to a plurality of playback blocks due to delay, encoded video and audio data can be stored in one of the other four data blocks. If an error occurs, the error directly leads to interruption of video and audio data.
[0078]
Next, the reproduction operation in the present embodiment will be described with reference to FIG. FIG. 7C shows an example in which it takes 1.3 [seconds] to read the reproduction block n for the same reason as explained in FIG. 7B, for example. Since the read time of the reproduction block n takes 950 [milliseconds] or more, the next hard disk device does not read the data of the reproduction block (n + 1) scheduled to be read next from the same hard disk, and the next The CPU 44 controls the reading operation of the hard disk so that the data of the reproduction block (n + 2) scheduled to be read out is read at a designated timing, for example, 2 [seconds] from the start of the reproduction operation.
[0079]
The data of the reproduction block (n + 1) that has not been read out is subjected to the error correction process described above by the error code decoder 34 from the four data blocks and error correction code data read by the other four hard disk devices. The data is restored by use and supplied to a predetermined decoder of the decoder unit 35.
[0080]
As a result, the read start timing after the reproduction block (n + 2) by the hard disk device is not delayed from the designated timing, and there is a possibility that the video and audio data supplied to the terminal device may be interrupted as shown in FIG. Compared to the case where the reproduction operation described with reference to the above is performed, it is lower.
[0081]
Next, an example of the operation of the main CPU 33 of the media control unit 26 will be described with reference to the flowchart shown in FIG.
[0082]
The main CPU 33 starts its operation at step SP0. In step SP1, the main CPU 33 waits until a reproduction control signal for distributing video and audio data requested from each terminal device to each terminal device is supplied from the control device 29 via the control line S2. When the reproduction control signal is supplied from the control device 29, the process proceeds to step SP2.
[0083]
In step SP2, the main CPU 33 generates a control signal for reproducing the requested encoded video and audio data and error correction code data from each hard disk based on the reproduction control signal for each reproduction block. Are supplied to the CPU 44 in each of the input / output units 32A to 32C via the control line S6.
[0084]
In step SP3, the main CPU 33 determines whether or not the supply of the data access command to the CPU 44 in the input / output units 32A to 32C has been completed. If a negative result “NO” is obtained, the main CPU 33 returns to step SP1 and confirms the positive result. When “YES” is obtained, the process proceeds to step SP4, a reproduction end instruction is supplied to the CPU 44 in the input / output units 32A to 32C, the process proceeds to step SP5, and the series of processes is terminated. Next, an example of the operation of the CPU 44 in the input / output units 32A to 32C will be described with reference to the flowchart shown in FIG.
[0085]
The CPU 44 starts its operation at step SP10. In step SP11, the CPU 44 receives the data access command described above from the main CPU 33, stores the contents of the data access command in an internal memory (not shown), and sets the reception time of the data access command in the timer 46 (FIG. 3). Remember. Each of the data access commands corresponds to each reproduction block of requested encoded video and audio data and error correction code data. Each data access command indicates the type of each corresponding reproduction block, the reproduction start timing, and the like.
[0086]
In step SP12, the CPU 44 sets each command content of the data access command in a standby state, and proceeds to step SP13. In step SP13, the CPU 44 refers to the elapsed time data supplied from the timer 46, and determines whether it is the reception end time, for example, whether the elapsed time data supplied from the timer 46 has exceeded 200 [milliseconds]. If the reception end time is not reached, the process returns to step SP11 to accept a further data access command from the main CPU 33.
[0087]
On the other hand, if it is determined that the reception end time has passed, for example, exceeding 200 [milliseconds] since the reception of the first data access command, the process proceeds to the next step SP14. In this way, the CPU 44 stores a plurality of data access commands by repeating step SP11 to step SP13 until the reception end time.
[0088]
In step SP14, the CPU 44 determines whether there is a command whose reproduction start timing indicated by the data access command has already passed among the waiting data access commands. If an affirmative result “YES” is obtained in step SP14, the CPU 44 proceeds to step SP21 to inform the main CPU 33 that the data access command whose reproduction start timing has already passed is deleted, and to transmit this data access command to the inside. Delete from memory. And it returns to step SP14 again.
[0089]
If a negative result “NO” is obtained in step SP14, the CPU 44 proceeds to step SP15, retrieves data indicating the recording position of the reproduction block indicated by each data access command from the FAT memory 47, and sorts the data indicating these recording positions. Supply to circuit 45. The sorting circuit 45 rearranges the data indicating the plurality of supplied recording positions, for example, from the outer peripheral side to the inner peripheral side of the hard disk so that the seek time is minimized.
[0090]
Next, in step SP16, the CPU 44 stores the encoded video and audio data and the error correction code data located on the outermost periphery on the hard disk based on the data indicating the recording positions rearranged in the sorting circuit 45 and the data indicating the reproduction start timing. The hard disk device is controlled so as to be read from the disk.
[0091]
In step SP17, the CPU 44 deletes the data access command executed in step SP16 from the internal memory.
[0092]
Next, in step SP18, the CPU 44 determines whether there is a waiting data access command in the internal memory. When a negative result “NO” is obtained in step SP18, the CPU 44 returns to step SP14, whereas when an affirmative result “YES” is obtained, the process proceeds to step SP19.
[0093]
In step SP19, the main CPU 33 determines whether or not a reproduction end instruction is supplied from the CPU 33, and when a negative result “NO” is obtained, the main CPU 33 returns to step SP11. Further, when an affirmative result “YES” is obtained in step SP19, the process proceeds to step SP20, and the series of processes is terminated.
[0094]
In this way, the server unit 25 can supply the requested video and audio data to the requested terminal device without interruption in response to requests from the terminal devices 28A1 to 28A12.
[0095]
In the above embodiment, the case where a hard disk is used has been described. However, a magneto-optical disk apparatus or an optical disk apparatus may be used as the disk apparatus.
[0096]
The data recording / reproducing apparatus and data recording / reproducing method of the present invention can also be applied to an AV server having only the server unit 25 as a main configuration.
[0097]
Furthermore, the data recording / reproducing apparatus and data recording / reproducing method of the present invention can be applied to systems other than the AV server system.
[0098]
Further, although the data supply source 22 of FIG. 1 is constituted by a video tape recorder, the data supply source 22 is not limited to this, and various recording means such as a video disk can be applied.
[0099]
【The invention's effect】
As described above, according to the present invention, when data corresponding to the first period is read, when the data is read from the disk device beyond the first period, the second after the first period. The data corresponding to the second period is not read, the data corresponding to the third period following the second period is read from the beginning of the third period, and the skipped data is read from the preceding and following blocks. Data recording / reproduction that can ensure real-time performance without delaying the supply of data and thus supply video signals to multiple channels without interruption. An apparatus and a data recording / reproducing method can be realized.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of an AV server system to which a data recording / reproducing apparatus of the present invention is applied.
FIG. 2 is a block diagram showing an embodiment of a server unit of the AV server system shown in FIG.
FIG. 3 is a block diagram illustrating an example of an input / output unit of the server unit illustrated in FIG. 2;
4 (A) to 4 (F) are schematic diagrams for explaining an embodiment of recording positions of video and audio data in the AV server system shown in FIG.
FIG. 5 is a schematic diagram showing an example of a recording format on a recording medium in the AV server system shown in FIG. 1;
6 is a schematic diagram showing an example of sector allocation to each area of the recording format shown in FIG. 5. FIG.
7 (A) to 7 (C) are schematic diagrams for explaining the operation of the data recording / reproducing apparatus of the present invention.
FIG. 8 is a flowchart illustrating an example of the operation of the main CPU of the server unit illustrated in FIG. 2;
FIG. 9 is a flowchart illustrating an example of the operation of the CPU of the input / output unit illustrated in FIG. 3;
[Explanation of symbols]
20... Audio / Video Server System, 21... Video Tape Recorder, 22... Data Supply Source, 23... Encoding Unit, 24. 27A7... Media unit, 28... Control unit, 29... Control device, 35. Device, 30 ... encoder interface, 31 ... error code encoder, 32A to 32C ... input / output unit, 33 ... main CPU, 44 ... CPU, 40, 41 ... buffer memory, 42, 43 interface, 47 ... ... FAT memory, 35A to 35L ... Decoder, 46 ... Timer, 45 ... Sorting circuit.

Claims (4)

A plurality of disk devices for recording and reproducing data including video and audio data;
A plurality of input / output means connected to the plurality of disk devices;
The data is sequentially input to the plurality of disk devices from the plurality of input / output means in block units, and a certain disk device exceeds the first period when reading data corresponding to the first period. When the data is output, the data corresponding to the second period following the first period is not read, and the data corresponding to the third period following the second period is read out from the third period. And a control means for controlling the input / output means so as to read from the beginning of the data recording / reproducing apparatus. further,
And a restoration processing means for restoring the data corresponding to the second period that has not been read out by using video, audio data, and error correction data corresponding to the second period of another disk device. The data recording / reproducing apparatus according to claim 1. A first step of recording data including video and audio data on a plurality of disk devices in order in block units;
A second step of reading the data recorded in the first step from the plurality of disk devices;
In the second step,
When the data corresponding to the first period is read from the disk device that exceeds the first period, the data corresponding to the second period subsequent to the first period is A data recording / reproducing method, characterized in that, without reading, data corresponding to a third period subsequent to the second period is controlled to be read from the beginning of the third period. further,
A third step of restoring the data corresponding to the second period that has not been read out with the video, audio data, and error correction data corresponding to the second period of another disk device; The data recording / reproducing method according to claim 3, wherein:

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