JP2000276856A - Device and method for recording data and device and method for reproducing data - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently suppress the occurrence of errors in data while securing a real time property in the case of recording and reproducing data such as compressed image data to which the real time property is requested. SOLUTION: In the case of recording data constituting an AV data stream on a magnetic disk 5, information showing the importance degree of a cluster is temporarily stored in a temporary storage register 34 for each cluster. While referring to the temporary storage register 34, an ECC circuit 41 recognizes the importance degree of a cluster to be recorded and the error-correcting code of a correction ability corresponding to the importance degree is added to the cluster.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a data recording apparatus and a data recording method for recording digital data on a recording medium such as a magnetic disk, and a data reproducing apparatus and a data reproducing method for reproducing digital data from a recording medium. .

[0002]

2. Description of the Related Art Conventionally, a magnetic disk in which a magnetic film is formed on a metal substrate such as aluminum whose surface has been polished with high precision is used as a recording medium, and a magnetic head is mounted on a data recording area of the magnetic disk. 2. Description of the Related Art Hard disk drives are widely used in which a mounted flying slider flies so that a magnetic head writes data in a data recording area of a magnetic disk or reads data recorded in a data recording area of a magnetic disk.

The hard disk drive has a very high data recording density, is capable of storing a large amount of data, and has a high speed access to the recorded data. It is widely used as a storage device for storing data to be processed.

FIG. 10 shows a configuration example of a signal processing circuit in a hard disk drive.

When digital data (hereinafter referred to as recording data) processed by a data processing device such as a host computer is recorded on a magnetic disk by the hard disk drive 100 shown in FIG. From the processing unit, the CPU (Centra
l Processing Unit) 101 is supplied with a recording command, and recording data is supplied to a host interface 103 in a hard disk controller 102.
The recording data supplied to the host interface 103 is temporarily stored in the buffer memory 105 under the control of the bus controller 104.

The CPU 101 instructs the sequencer 106 on which sector on the magnetic disk the recording data is to be recorded, based on a recording command supplied from a data processing device such as a host computer.

To position the magnetic head on the magnetic disk, the servo control circuit 107 calculates the current position of the magnetic head based on the position information detected by the magnetic head, and the VCM according to the current position of the magnetic head. (Vo
This is performed by controlling the driving current of an ice coil motor).

When the sequencer 106 confirms that the magnetic head is at the target position, the sequencer 106 reads the recording data from the buffer memory 105, and reads the recording data into the ECC (Er
rorCorrecting Code) circuit 108. The recording data supplied to the ECC circuit 108
08, the error correction code is added, and the channel IC 110
Is forwarded to The channel IC 110 performs processing such as channel encoding on the recording data transferred via the disk interface 109, and converts the recording data into a binary sequence signal. Then, the binary series signal is written on the magnetic disk as a magnetization reversal pattern by the magnetic head. The operation timing of the disk interface 109 is controlled by the sequencer 106.

When the servo control circuit 107 detects that it is difficult to continue normal operation due to an excessive position signal from the magnetic head while recording data is being recorded on the magnetic disk, the sequencer 106 Shifts to the retry (retry) mode, and performs the operation of recording the same sector again. Information that it is difficult to continue normal operation
In some cases, the signal is supplied directly from the servo control circuit 107 to the sequencer 106, and in another case, the signal is supplied to the sequencer 106 via the CPU 101.

On the other hand, the hard disk drive 100
When reproducing data recorded on a magnetic disk, a reproduction command is first supplied from a data processing device such as a host computer to the CPU 101, and a magnetization reversal pattern is read from the magnetic disk by a magnetic head.

For positioning of the magnetic head on the magnetic disk, the servo control circuit 107 calculates the current position of the magnetic head based on the position information detected by the magnetic head. This is performed by controlling the drive current of.

The magnetization reversal pattern read from the magnetic disk by the magnetic head is subjected to waveform equalization, signal detection, decoding of a channel code, and the like by the channel IC 110, and is restored to digital data (hereinafter referred to as reproduction data). Is done. This reproduced data may include an error in some cases, but is transferred to the disk interface 109 in the hard disk controller 102 as it is.

The operation timing of the disk interface 109 is controlled by the sequencer 106. When the sequencer 106 confirms that the magnetic head is at the target position, the sequencer 106 fetches the reproduction data from the channel IC 110 through the disk interface 109 and
The reproduced data is supplied to the ECC circuit 108.

The ECC circuit 108 performs error correction and error detection by decoding the error correction code added to the reproduced data. For example, when the error correction code of 8 symbols is added to the reproduction data, the ECC circuit 1
08 can correct an error in the reproduction data up to four symbols. However, if the number of symbols to be corrected is increased, the time required for error correction becomes longer and the processing speed becomes slower. Therefore, normally, the correction capability of the ECC circuit 108 is not used to the utmost, and for example, In the above example, error correction for up to two symbols is performed. And
When it is detected that the reproduced data after the correction further includes an error, the sequencer 106 shifts to the retry mode,
An operation of reproducing the same sector again is performed. In this case,
Error correction of reproduced data is performed by making full use of the correction capability of the ECC circuit 108.

As described above, the hard disk drive 100 normally performs high-speed decoding and improves retry and correction capabilities only when an error occurs, thereby ensuring data reliability while maintaining the overall reliability. Has been made to increase the processing speed.

The reproduced data on which error correction and error detection have been performed by the ECC circuit 108 are transmitted to the bus controller 104.
Is temporarily stored in the buffer memory 105. Then, the reproduction data stored in the buffer memory 105 is sequentially transferred to a data processing device such as a host computer via the host interface 103.

[0017]

By the way, with the development of digital technology in recent years, digitized moving image data is frequently processed on a computer. It is required to use a hard disk drive as a means for storing the moving image data processed on the computer.

Generally, such moving image data is MPE
It is handled in a form encoded by a G (Moving Picture Experts Group) encoding method. This method is an encoding method for compressing the moving image data using correlation (spatial correlation) in each frame constituting the moving image data, correlation (temporal correlation) between the frames, and the like. By performing processing after compression in such a manner, processing efficiency can be improved.

When recording and reproducing such moving image data, a so-called real-time property for recording and reproducing a data stream constituting the moving image without interruption is required. For this reason, when reproducing moving image data using a hard disk drive, a process of outputting data containing an error as it is without performing a retry operation in which a temporal uncertain element exists. In this case, a process is generally performed in which the data including the error is complemented from the data before and after the data including the error so that the moving image data is less uncomfortable.

As described above, when data that requires real-time properties such as moving picture data is reproduced using a hard disk drive, a retry operation is performed as compared with the case where data that does not require real-time properties is reproduced. There is a problem that the probability that an error is included in the reproduced data is increased by an amount corresponding to the absence. Also, if the number of symbols to be corrected at the time of performing error correction is increased to reduce the probability of occurrence of errors in the reproduced data, the time required for error correction becomes longer, the processing speed becomes slower, and real-time performance is reduced. Will be impaired.

In particular, when moving image data is encoded by the above-described MPEG encoding method, this moving image data includes an I-picture (Intra-Picture: intra-frame coded image) compressed using only the correlation within the frame. ) And a P-picture (Pred
ictive-Picture: Inter-frame forward prediction coded image)
And a B picture (Bidirectionally predictive-Picture: bidirectionally predictive coded image) compressed using the correlation with the preceding and following frames. And I
Since a picture is data that is the source of all pictures constituting a GOP (Group of Pictures), which is a block of data used for encoding, if an error occurs in this I picture, the GOP is All the constituent pictures are not correctly decoded, and the quality of the reproduced image data is significantly deteriorated.

The present invention has been made in view of the above-described conventional problems, and it is possible to efficiently suppress occurrence of data errors while ensuring real-time performance during reproduction.
Provided is a data recording device and a data recording method for recording data so that high-quality data is reproduced. In addition, the present invention reproduces high-quality data by efficiently suppressing the occurrence of data errors while ensuring real-time performance. It is an object of the present invention to provide a data reproducing apparatus and a data reproducing method capable of performing the above.

[0023]

A data recording apparatus according to the present invention is a data recording apparatus for recording compressed image data on a recording medium. Means for temporarily storing information indicating the degree of error, and based on the information stored in the storage means, for each data block serving as a recording unit, an error correction code having a different correction capability depending on the importance of the data block. And an error correction code adding means for adding.

In this data recording apparatus, when recording compressed image data, the importance of the data block is recognized for each data block serving as a recording unit, and information indicating the importance of the data block is represented by: It is temporarily stored in the storage means.

The error correction code adding means adds an error correction code having a different correction capability to each data block based on the information indicating the importance of the data block temporarily stored in the storage means.

More specifically, for example, in the case where this data recording apparatus records moving image data compressed by the MPEG encoding method, for each frame constituting the moving image, whether the frame is an I picture , P picture or B picture
Whether the picture is a picture is recognized, and the information is temporarily stored in the storage means.

Then, the error correction code adding means, for each frame, based on the information temporarily stored in the storage means,
Error correction codes having different correction capabilities are added according to the importance. Specifically, the error correction code adding means adds, for example, an error correction code having a large code amount to an I picture, and a code amount to the P picture, which is larger than the error correction code added to the I picture. , And a process of adding an error correction code having a smaller code amount to the B picture than the error correction code added to the P picture.

As described above, the image data recorded by the data recording apparatus is provided with an error correction code corresponding to the importance of each data block as a recording unit. In such a case, for example, an error correction process is performed for a data block with a high importance such as an I picture over time, and a data block with a relatively low importance such as a B picture is used for an error correction process. Means that the time of the error correction processing is reduced. As a result, the processing time of this image data as a whole is shortened, real-time performance is ensured, and the occurrence of errors is efficiently suppressed, and the reliability of the data is improved.

Another data recording apparatus according to the present invention is a data recording apparatus for recording digital data on a recording medium, wherein the digital data to be recorded is compressed image data or other data. Discriminating means for discriminating whether the digital data to be recorded is compressed image data, and for each data block serving as a recording unit, information indicating the importance of the data block. There is provided a storage means for temporarily storing and an error correction code adding means for adding an error correction code to digital data to be recorded. If the digital data to be recorded is judged to be compressed image data by the discriminating means, the error correcting code adding means records the data based on the information stored in the memory means. An error correction code having a different correction capability is added to each data block as a unit according to the importance of the data block, and if the digital data to be recorded is determined to be other data by the determination means, an error occurs. The correction code adding means adds an error correction code having a fixed correction capability.

In this data recording apparatus, when digital data is recorded, it is determined by the determining means whether the digital data is compressed image data requiring real-time processing or other data. Is done. When it is determined that the digital data is compressed image data, the importance of the data block is recognized for each data block serving as a recording unit, and information indicating the importance of the data block is stored. It is temporarily stored in the means.

When it is determined that the digital data to be recorded is compressed image data, the error correction code adding means determines the data block based on the information indicating the importance of the data block temporarily stored in the storage means. An error correction code having a different correction capability is added for each. When it is determined that the digital data to be recorded is data other than the compressed image data, the error correction code adding means adds an error correction code having a fixed correction capability to the digital data.

When digital data recorded by this data recording apparatus is compressed image data requiring real-time processing, the digital data is recorded in units of data blocks as recording units as described above. Since an error correction code according to importance is added, when this image data is reproduced, it takes time to perform error correction processing on a data block with high importance such as an I picture. Is performed, and the time of the error correction processing is shortened for data having relatively low importance such as a B picture. Thus, this image data is
The processing time as a whole is shortened, real-time performance is ensured, and the occurrence of errors is efficiently suppressed, and the reliability of data is improved.

When digital data recorded by the data recording apparatus is data other than the compressed image data, an error correction code having a fixed correction capability is added to the digital data. When digital data is reproduced, error correction processing is performed over time for all data blocks, or
By performing the retry operation as needed, the real-time property is impaired, but the occurrence of errors is effectively suppressed, and the reliability of data is greatly improved.

According to the data recording method of the present invention, when recording compressed image data on a recording medium, for each data block serving as a recording unit, information indicating the importance of the data block is temporarily stored. Then, based on the temporarily stored information, an error correction code having a different correction capability is added to each data block as a recording unit according to the importance of the data block.

More specifically, for example, when moving image data compressed by the MPEG encoding method by this data recording method is to be recorded, for each frame constituting the moving image, whether the frame is an I picture, Whether it is a P picture
Whether the picture is a B picture is recognized, and the information is temporarily stored.

Then, based on the temporarily stored information,
An error correction code having a different correction capability is added to each frame according to its importance. Specifically, for example, an error correction code having a larger code amount is added to an I picture, and an error correction code having a smaller code amount than an error correction code added to an I picture is added to a P picture. A process is performed such that an error correction code having a smaller code amount than the error correction code added to the P picture is added to the B picture.

As described above, the image data recorded by this data recording method is provided with an error correction code according to its importance for each data block serving as a recording unit. In such a case, for example, an error correction process is performed for a data block with a high importance such as an I picture over time, and a data block with a relatively low importance such as a B picture is used for an error correction process. Means that the time of the error correction processing is reduced. As a result, the processing time of this image data as a whole is shortened, real-time performance is ensured, and the occurrence of errors is efficiently suppressed, and the reliability of the data is improved.

In another data recording method according to the present invention, when recording digital data on a recording medium, it is determined whether the digital data to be recorded is compressed image data or other data. When it is determined that the digital data to be recorded is compressed image data,
Information indicating the importance of the data block is temporarily stored, and based on the temporarily stored information, an error correction code having a different correction capability according to the importance of the data block for each data block serving as a recording unit. Is added, and when it is determined that the digital data to be recorded is other data, an error correction code having a fixed correction capability is added.

When digital data recorded by this data recording method is compressed image data that requires real-time processing, as described above, the digital data is stored in units of data blocks as recording units. Since an error correction code according to importance is added, when this image data is reproduced, it takes time to perform error correction processing on a data block with high importance such as an I picture. Is performed, and the time of the error correction processing is shortened for data having relatively low importance such as a B picture. Thus, this image data is
The processing time as a whole is shortened, real-time performance is ensured, and the occurrence of errors is efficiently suppressed, and the reliability of data is improved.

When digital data recorded by this data recording method is data other than the compressed image data, an error correction code having a fixed correction capability is added. When digital data is reproduced, error correction processing is performed over time for all data blocks, or
By performing the retry operation as needed, the real-time property is impaired, but the occurrence of errors is effectively suppressed, and the reliability of data is greatly improved.

According to the data reproducing apparatus of the present invention, in a data reproducing apparatus for reproducing compressed image data from a recording medium, information indicating the importance of the data block is temporarily stored for each data block as a reproduction unit. Based on storage means for storing, and information stored in the storage means,
An error correction unit is provided for each data block serving as a reproduction unit, which performs error correction with different correction capabilities according to the importance of the data block.

In this data reproducing apparatus, when reproducing compressed image data from a recording medium, the importance of the data block is recognized for each data block as a reproduction unit, and the importance of the data block is indicated. Information
It is temporarily stored in the storage means.

The error correction means performs error correction with a different correction capability for each data block based on the information indicating the importance of the data block temporarily stored in the storage means.

More specifically, for example, when the data reproducing apparatus reproduces moving image data compressed by the MPEG encoding method, for each frame constituting the moving image, it is determined whether the frame is an I picture. , P picture or B picture
Whether the picture is a picture is recognized, and the information is temporarily stored in the storage means.

The error correction means performs error correction for each frame with a different correction capability according to its importance, based on the information temporarily stored in the storage means. Specifically, for example, the error correction unit performs error correction by decoding an error correction code having a large code amount for an I picture,
For a picture, error correction is performed by decoding an error correction code having a smaller code amount than that of an I picture, and for a B picture, an error correction code having a code amount smaller than that of a P picture is decoded. Is performed.

According to this data reproducing apparatus, as described above, error correction is performed with a different correction capability depending on the importance of each data block serving as a reproduction unit. The error correction processing is performed for data blocks with high importance over time, and the time for error correction processing for data with relatively low importance such as B pictures is reduced. . As a result, the image data reproduced by the data reproducing apparatus is reduced in overall processing time, real-time property is secured, and the occurrence of errors is efficiently suppressed, thereby improving the data reliability. become.

Another data reproducing apparatus according to the present invention is a data reproducing apparatus for reproducing digital data from a recording medium, which determines whether the digital data to be reproduced is compressed image data or other data. Discriminating means for discriminating, and when the discriminating means discriminates that the digital data to be reproduced is compressed image data, temporarily stores, for each data block serving as a reproduction unit, information indicating the importance of the data block. And error correction means for performing error correction on digital data to be reproduced. If the digital data to be reproduced is determined to be compressed image data by the determination means, the error correction means determines the reproduction unit based on the information stored in the storage means. For each data block, error correction is performed with different correction capabilities according to the importance of the data block, and when the digital data to be reproduced is determined to be other data by the determination unit, the error correction unit It is characterized by performing error correction with a fixed correction capability.

In the data reproducing apparatus, when reproducing digital data from a recording medium, it is determined whether the digital data is compressed image data requiring real-time performance or other data. It is determined by means. When it is determined that the digital data is compressed image data, the importance of the data block is recognized for each data block serving as a reproduction unit, and information indicating the importance of the data block is stored. It is temporarily stored in the means.

When the error correction means determines that the digital data to be reproduced is compressed image data,
Error correction is performed with a different correction capability for each data block based on the information indicating the importance of the data block temporarily stored in the storage unit. When it is determined that the digital data to be reproduced is data other than the compressed image data, the error correction means performs error correction on the digital data with a fixed correction capability.

As described above, when the digital data to be reproduced is compressed image data that requires real-time processing, the data reproducing apparatus performs the reproduction according to the importance of each data block as a reproduction unit. Error correction processing is performed with the corrected correction capability, for example, like an I picture,
The error correction processing is performed for data blocks with high importance over time, and the time for error correction processing for data with relatively low importance such as B pictures is reduced. . As a result, the compressed image data reproduced by the data reproducing apparatus is shortened in overall processing time and secured in real time, and the occurrence of errors is efficiently suppressed, and the reliability of the data is reduced. Will be improved.

Further, as described above, when the digital data to be reproduced is data other than the compressed image data, the data recording apparatus performs error correction processing on the digital data with a fixed correction capability. Therefore, for example, by performing error correction processing over time for all data blocks, or by performing a retry operation as necessary, effectively suppressing errors in the digital data, Data reliability can be greatly improved. In this case, the real-time property is impaired. However, since the digital data to be reproduced is not the compressed image data requiring the real-time property, there is no problem.

In the data reproducing method according to the present invention, when reproducing compressed image data from a recording medium, information indicating the importance of the data block is temporarily stored for each data block as a reproduction unit, On the basis of the temporarily stored information, error correction is performed for each data block as a reproduction unit with different correction capabilities according to the importance of the data block.

Specifically, for example, in the case of reproducing moving image data compressed by the MPEG encoding method by this data reproducing method, for each frame constituting the moving image, whether the frame is an I picture, Whether it is a P picture
Whether the picture is a B picture is recognized, and the information is temporarily stored.

Then, based on the temporarily stored information,
For each frame, error correction is performed with different correction capabilities according to the importance. More specifically, for example, an I-picture is decoded with an error correction code having a large code amount to perform error correction, and a P-picture is decoded with an error correction code having a code amount smaller than that of the I picture. Then, error correction is performed on the B picture, and error correction codes with a smaller code amount than the P picture are decoded and error correction is performed on the B picture.

According to this data reproducing method, as described above, error correction is performed with a different correction capability depending on the importance of each data block serving as a reproduction unit. The error correction processing is performed for data blocks with high importance over time, and the time for error correction processing for data with relatively low importance such as B pictures is reduced. . As a result, the image data reproduced by this data reproducing method has a shorter processing time as a whole, and real-time performance is ensured. In addition, the occurrence of errors is efficiently suppressed, and the reliability of the data is improved. become.

In another data reproducing method according to the present invention, when reproducing digital data from a recording medium,
It is determined whether the digital data to be reproduced is compressed image data or other data. If the digital data to be reproduced is determined to be compressed image data, a data block serving as a reproduction unit is determined. For each data block, information indicating the importance of the data block is temporarily stored, and based on the temporarily stored information, for each data block serving as a reproduction unit, with a different correction capability according to the importance of the data block. It is characterized in that error correction is performed, and when digital data to be reproduced is determined to be other data, error correction is performed with a fixed correction capability.

According to this data reproducing method, as described above, when the digital data to be reproduced is compressed image data requiring real-time processing, the importance of each data block as a reproduction unit is determined. The error correction processing is performed with the correction capability according to. For example, the error correction processing is performed over a long time for a data block with high importance like an I picture,
For data of relatively low importance, the time for error correction processing is reduced. As a result, the compressed image data reproduced by this data reproducing method can be processed in a shorter time as a whole, real-time performance can be ensured, errors can be suppressed efficiently, and data reliability can be reduced. Will be improved.

According to this data recording method, as described above, when the digital data to be reproduced is data other than the compressed image data, the digital data is subjected to error correction with a fixed correction capability. Since the processing is performed, for example, error correction processing is performed for all data blocks over time, or a retry operation is performed as necessary, thereby effectively reducing the error of the digital data. , And the reliability of data can be greatly improved. In this case, the real-time property is impaired. However, since the digital data to be reproduced is not the compressed image data requiring the real-time property, there is no problem.

[0059]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a data recording / reproducing apparatus to which the present invention is applied will be described below with reference to the drawings. In the following description, an example will be described in which a data recording / reproducing apparatus is configured using a fixed hard disk drive in which a magnetic disk is provided in advance in the apparatus main body, but the present invention is not limited to this example. Instead, for example, it may be configured using another external storage device such as a removable hard disk drive configured to be capable of inserting and removing a magnetic disk into and from the apparatus main body, and an optical disk drive using an optical disk as a recording medium. It is possible.

FIG. 1 shows an example of the configuration of a data recording / reproducing apparatus to which the present invention is applied. The data recording / reproducing device 1 shown in FIG. 1 has a configuration in which a host-side data processing device 2 and a hard disk drive 3 serving as an external storage device are connected via a host interface bus 4. 2. The digital video data and digital audio data processed in step 2 are recorded on the magnetic disk 5 in the hard disk drive 3, and the digital video data and digital audio data recorded on the magnetic disk 5 in the hard disk drive 3 are reproduced. It has been made possible. As the host interface, for example, the extended IDE standard (ATA standard)
Is used.

The overall operation of the data recording / reproducing device 1 is managed by the CPU-A 6 in the data processing device 2. A ROM 8 and a RAM 9 are connected to the CPU-A 6 via a CPU-A bus 7, respectively. Firmware for the CPU-A 6 to manage the entire operation of the data recording / reproducing apparatus 1 is stored in the ROM 8. The RAM 9 is used as a work area of the CPU-A6.

The data recording / reproducing apparatus 1 is provided with a switch, a remote controller, a keyboard, a liquid crystal display, and the like (not shown) as a user interface mechanism. The input from the user interface mechanism or the output to the user interface mechanism is managed by the CPU-A6.

The CPU-A 6 is connected to the CPU-A bus 7
Is connected to the AV interface 10. In the data recording / reproducing apparatus 1, an instruction to write data to the magnetic disk 5 by the hard disk drive 3 or an instruction to read data from the magnetic disk 5 by the hard disk drive 3 is issued by the CPU-A.
6 is performed by issuing a recording command or a reproduction command defined in the extended IDE standard from the AV interface 10 to the hard disk drive 3.

The CPU-A 6 is connected to the CPU-A bus 7
Is connected to the memory control circuit 11 via the. The memory control circuit 11 compresses and multiplexes the input image signals and audio signals and outputs the resulting signals as an AV data stream. The memory control circuit 11 converts the AV data stream read from the magnetic disk 5 by the hard disk drive 3 into an image. It is separated into data and audio data, and is connected to an AV decoder 13 which interpolates and expands these and outputs them as normal image signals and audio signals. The memory control circuit 11 has a host memory 1 for temporarily storing data supplied to the hard disk drive 3 or data supplied from the hard disk drive 3.
4 are connected.

FIG. 2 shows a hierarchical structure of firmware stored in the ROM 8 and executed by the CPU-A 6. As shown in FIG. 2, a first layer below the firmware includes a user interface unit for performing input / output with respect to the user interface mechanism, and an encoder for controlling the operations of the AV encoder 12 and the AV decoder 13. A decoder management unit, a host memory management unit for controlling the operation of writing and reading data to and from the host memory 14 by the memory control circuit 11, and a hard disk drive for operating each device provided in the hard disk drive 3 It is built with device drivers.

The upper second layer of the firmware manages each component constituting the lower first layer, and is constructed by system management software which controls the operation of the entire data recording / reproducing apparatus 1. The functions of the system management software include a data recording / reproducing device, such as instructing and managing recording and reproducing operations of each channel, and grasping and managing the operating status of each hardware resource such as the hard disk drive 3 and the host memory 14. 1 includes all functions that are not included in the lower first layer.

The flow of processing for recording data on the magnetic disk 5 of the hard disk drive 3 by the data recording / reproducing apparatus 1 configured as described above will be described. When data is recorded on the magnetic disk 5 of the hard disk drive 3 by the data recording / reproducing apparatus 1, first, an analog image signal such as an NTSC signal and an analog sound signal are converted into digital data by an A / D converter (not shown). , And then input to the AV encoder 12.

The digital image data input to the AV encoder 12 is compressed by the image data compressor 15 in the AV encoder 12 to a data rate of, for example, about 1/5. The digital audio data input to the AV encoder 12 is compressed by an audio data compressor 16 in the AV encoder 12. As a data compression method, a DV coding method, an MPEG coding method, and the like have been put to practical use. According to these data compression methods, the original digital data is subjected to discrete cosine transform, inter-frame motion detection, requantization, two-dimensional Huffman coding, and the like, thereby compressing the data rate.

The digital image data compressed by the image data compressor 15 and the digital audio data compressed by the audio data compressor 16 are multiplexed in the MUX 17 to form an AV data stream.
Here, an example will be described in which the MPEG2 encoding method is used as the data compression method, and the data rate of the AV data stream is 8 Mbit / sec.

This AV data stream is temporarily written into the host memory 14 via the memory control circuit 11 once. Then, the CPU-A 6 issues an instruction to the memory control circuit 11 in accordance with the host memory management unit of the firmware, so that clusters, which are groups of data to be recorded on the magnetic disk 5 of the hard disk drive 3, are sequentially read from the host memory 14. Is read.

The clusters sequentially read from the host memory 14 are sent out of the data processing device 2 via the AV interface 10 and supplied to the hard disk drive 3 via the host interface bus 4. Then, the clusters supplied to the hard disk drive 3 are sequentially recorded on the magnetic disk 5 by the hard disk drive 3.

FIG. 3 shows the relationship between a cluster, which is a data recording unit in the data recording / reproducing apparatus of this embodiment, and a GOP (Group of Pictures) defined by the MPEG2 encoding method. In the data recording / reproducing apparatus of this example, as shown in FIG. 3, a cluster is a group of data obtained by dividing an AV data stream for each picture constituting a GOP. The GOP is composed of 15 pictures, that is, 15 frames of images. here,
Since one frame is equivalent to 1/30 second, one GOP
Is equivalent to 0.5 seconds. In the data recording / reproducing apparatus of the present example, since the data rate of the AV data stream is 8 Mbit / sec, one GO
The data amount of P is 4 Mbit. Therefore, this G
The data amount of one cluster obtained by dividing the OP into 15 is several tens kbits to several Mbits.

On the other hand, the size of the sector which is the minimum recording unit of the hard disk drive 3 is 512 bytes (409
6 bits). Therefore, each cluster is allocated a number of sectors corresponding to the size of the corresponding picture. That is, when a recording command is issued from the data processing device 2, the hard disk drive 3 continuously records sectors for one cluster based on the recording command.

Here, the data to be recorded is recorded on the magnetic disk 5 after an error correction code is added in the hard disk drive 3. For example, the data to be recorded is divided into three interleaves for each sector having a data amount of 512 bytes as shown in FIG. It is recorded on the magnetic disk 5. The recorded data is, for example,
14B by Reed-Solomon code for each interleave
When an error correction code of byte is added, up to 7 bytes of error correction can be performed for each interleave during reproduction.

The data recording / reproducing apparatus 1 according to the present invention adds an error correction code having a different correction capability depending on the importance of each cluster to be recorded.
If the cluster to be recorded is data constituting an I picture of a GOP, an error correction code having a high correction capability is added to this cluster, and the cluster to be recorded is a GOP.
If the data is data constituting a P picture, an error correction code having a lower correction capability than the error correction code added to the data constituting the I picture is added to this cluster, and the cluster to be recorded is a GOP. If the data constitutes the B picture of
An error correction code having a lower correction capability than the error correction code added to the data constituting the P picture is added. This will be described later in detail.

Next, the flow of processing for reproducing data recorded on the magnetic disk 5 of the hard disk drive 3 by the data recording / reproducing apparatus 1 will be described. When reproducing the data recorded on the magnetic disk 5 of the hard disk drive 3 by the data recording / reproducing apparatus 1, first, the CPU-A6 of the data processing apparatus 2 uses the user interface unit by the firmware system management software. The AV data stream name to be reproduced is specified in accordance with the input information from, and the logical block address in the hard disk drive 3 where each cluster constituting the AV data stream is recorded is obtained. And C
The PU-A 6 issues a playback command defined on the host interface bus 4 to the hard disk drive 3 by a hard disk device driver of firmware. The hard disk drive 3 reads each sector constituting the cluster from the magnetic disk 5 based on the reproduction command.

The CPU-A 6 reconfigures the cluster from the sector read from the magnetic disk 5 by the hard disk drive 3 to the host memory 14 through the memory control circuit 11 by the host memory management unit of the firmware. Storage area.

Here, each sector constituting the cluster read from the magnetic disk 5 is subjected to error correction processing in the hard disk drive 3 and then supplied to the data processing device 2 via the host interface bus 4. Is done.

The data recording / reproducing apparatus 1 according to the present invention performs error correction with different correction capabilities depending on the importance of each cluster to be reproduced. If the data is a component of the GOP, an error correction process with a high correction capability is performed on the cluster. If the cluster to be reproduced is data constituting a P-picture of a GOP, Performing error correction processing having a lower correction capability than the error correction processing performed on the data constituting the I picture;
If the cluster to be reproduced is the data constituting the B picture of the GOP, error correction processing having a lower correction capability than that performed on the data constituting the P picture is performed on this cluster. But
This will be described later in detail.

Each sector read from the magnetic disk 5 by the hard disk drive 3 is sequentially transferred to the host memory 14 via the host interface bus 4, the AV interface 10, and the memory control circuit 11, and the host memory 14 Reconfigured as a cluster.

When reading of one cluster is completed,
As in the above-described processing, a reproduction command is issued to the hard disk drive 3 by the CPU-A 6, and the hard disk drive 3 reads each sector forming a subsequent cluster from the magnetic disk 5. Then, each sector read from the magnetic disk 5 is transferred to the host memory 14, and the subsequent cluster is reconfigured in the host memory 14.

The clusters reconstructed in the host memory 14 are sequentially sent from the host memory 14,
The data is input to the AV decoder 13 via the memory control circuit 11 as an AV data stream. AV decoder 1
The AV data stream input to 3 is demultiplexed by the MUX 18 in the AV decoder 13 and separated into compressed digital image data and compressed digital audio data.

If an error occurs in the compressed digital image data separated by the MUX 18, the error is interpolated in the image data interpolation circuit 19 from the data before and after the error. Then, the compressed digital image data is expanded by the image data expander 20 and output from the AV decoder 13 as normal digital image data.

On the other hand, if the compressed digital audio data separated by the MUX 18 has an error in the data, the audio data interpolation circuit 21 interpolates the error from the data before and after the error. The compressed digital audio data is sent to the audio data expander 22.
And expanded as normal digital sound data by A
It is output from the V decoder 13.

These digital image data and digital sound data are converted into analog image signals and analog sound signals such as NTSC signals by a D / A converter (not shown) and supplied to an external device such as a monitor.

FIG. 5 shows a recording command issued by the CPU-A 6 of the data processing device 2 to the hard disk drive 3 via the host interface bus 4 in the data recording / reproducing device 1 according to the present invention.

This recording command specifies the number of sectors to be written in the Sector Count register in the same manner as the ATA standard recording command.
derLow register, Cylinder High register and Device / H
The lower 4 bits of the ead register specify the write start logical block address. In this recording command, the command type is specified in the Command register.
For example, in this Command register, the command identification code 8
7h indicates that this command is a command for recording data of the AV data stream. In this recording command, the attribute of the cluster to be recorded is specified in the Features register. For example, when the AV data stream is data compressed by the MPEG encoding method, this Features register is used. , It is determined whether the cluster to be recorded is an I picture, a P picture, or a B picture.

FIG. 6 shows a reproduction command issued by the CPU-A 6 of the data processing device 2 to the hard disk drive 3 via the host interface bus 4 in the data recording / reproducing device 1 according to the present invention.

In the case of this playback command, the number of sectors to be read is specified in the Sector Count register, as in the case of the ATA standard playback command.
derLow register, Cylinder High register and Device / H
The read start logical block address is specified by the lower 4 bits of the ead register. In this playback command, the command type is specified in the Command register.
For example, in this Command register, the command identification code 8
6h indicates that this command is a command for reproducing the data of the AV data stream. In this recording command, the attribute of the cluster to be reproduced is specified in the Features register. For example, when the AV data stream is data compressed by the MPEG encoding method, this Features register is used. , It is determined whether the cluster to be reproduced is an I picture, a P picture, or a B picture.

FIG. 7 shows a detailed block diagram in the hard disk drive 3 of the data recording / reproducing apparatus 1 according to the present invention. The flow of the process of writing data supplied from the data processing device 2 to the magnetic disk 5 by the hard disk drive 3 will be described below.

The data supplied from the data processing device 2 is transferred to the magnetic disk 5 by the hard disk drive 3.
First, the CPU-A of the data processing device 2
6, a recording command issued via the host interface bus 4 is transmitted to the hard disk controller 30.
Is supplied to the CPU-B31 via the. In particular,
This recording command is input to the host interface 32 in the hard disk controller 30 connected to the data processing device 2 via the host interface bus 4 for each cluster to be recorded, and the recording command input to this host interface 32 is Are transferred to the CPU-B 31 connected to the host interface 32 via the CPU-B bus 33.

The host interface 32 in the hard disk controller 30 has a data processor 2
, Data to be recorded is supplied for each cluster via the host interface bus 4.

When the recording command is supplied, the CPU-B 31 cooperates with the hard disk controller 30 to
The logical block address of the cluster supplied from the data processing device 2 to the host interface 32 is converted into a physical address inside the hard disk drive 3 (for example, disk surface number, track number, sector number, etc.).

Further, the CPU-B 31 reads the attribute of the cluster to be recorded (for example, whether the cluster to be recorded is an I picture,
(A picture or a B picture), and the information to that effect is stored in the temporary storage register 34 in the hard disk controller 30.

The cluster supplied to the host interface 32 has a data amount of several sectors, for example, 256 sectors, and these several sectors of data are temporarily stored in the buffer memory 36 under the control of the bus controller 35. .

Further, the CPU-B 31 instructs the sequencer 37 on which sector on the magnetic disk 5 the cluster supplied from the data processing device 2 is to be recorded.

The magnetic head 38 on the magnetic disk 5
The servo control circuit 39 that has received the target track number from the CPU-B 31 and the host interface 32 determines the current position of the magnetic head 38 based on the track number on the magnetic disk 5 detected by the magnetic head 38. VCM (Voice) for calculating and moving the magnetic head 38 in accordance with the current position of the magnetic head 38
This is performed by controlling the drive current of a Coil Motor 40.

When the sequencer 37 confirms that the magnetic head 38 is at the target position, the sequencer 37 stores the cluster temporarily stored in the buffer memory 36 into the hard disk drive 3.
Length of the logical data sector set in (512 Bytes)
e), and sequentially read out from the buffer memory 36.

The cluster read from the buffer memory 36 is supplied to an ECC (Error Correcting Code) circuit 41, where the ECC circuit 41 adds an error correction code to each sector.

The ECC circuit 41 can add an error correction code having a different correction capability according to the attribute (importance) of the cluster. That is, the ECC circuit 41 identifies the supplied cluster attribute by referring to the temporary storage register 34 in which information indicating the attribute of the cluster to be recorded is stored.
If this cluster is a GOP I-picture, an error correction code with a large code amount is added to this cluster. If the supplied cluster is a P-picture,
To this cluster, an error correction code having a code amount equivalent to or smaller than the error correction code added to the cluster of the I picture is added. If the supplied cluster is a B picture, For a cluster, P
It is configured such that an error correction code having a code amount equal to or smaller than the error correction code added to the cluster of pictures can be added.

Specifically, when a cluster of I pictures is supplied, the ECC circuit 41 adds, for example, a 42-byte error correction code to the cluster,
When a cluster of P pictures is supplied, an error correction code of, for example, 30 bytes is added to the cluster. When a cluster of B pictures is supplied, for example, an error correction code of 21 bytes is added to the cluster. Is added. Note that E
The code amount of the error correction code added by the CC circuit 41 to each of the I picture cluster, the P picture cluster, and the B picture cluster is not limited to the above example. When the code amount of the correction code is m1, the code amount of the error correction code added to the P picture cluster is m2, and the code amount of the error correction code added to the B picture cluster is m3,
An error correction code having a code amount satisfying m1 ≧ m2 ≧ m3 may be added.

Each sector constituting the cluster to which the error correction code has been added in the ECC circuit 41 is synchronized with the rotation of the magnetic disk 5 rotated by the spindle motor 42 in the channel IC 44 via the disk interface 43. Is transferred to the recording channel circuit 45. The rotation speed of the magnetic disk 5 by the spindle motor 42 is controlled by a spindle motor control circuit 46.
Is controlled by

The recording channel circuit 45 in the channel IC 44 performs a process such as channel coding on each sector transferred through the disk interface 43, and transfers these sectors from the magnetic head 38 and the magnetic disk 5. Is converted into a binary sequence signal suitable for the characteristics of the recording channel. Then, the signal of this binary sequence is
The recording amplifier 47 associates the recording current waveform with a rectangular recording current waveform, and writes the magnetization reversal pattern on the magnetic disk 5 by the magnetic head 38. The operation timing of the disk interface 43 is determined by the sequencer 37
Is controlled by

Next, the flow of a process of reading data from the magnetic disk 5 and supplying the data to the data processing device 2 by the hard disk drive 3 shown in FIG. 7 will be described below. When data is read from the magnetic disk 5 by the hard disk drive 3 and supplied to the data processing device 2, first, a playback command issued via the host interface bus 4 by the CPU-A 6 of the data processing device 2 It is supplied to the CPU-B31 via the controller 30. Specifically, the reproduction command is input to the host interface 32 in the hard disk controller 30 connected to the data processing device 2 via the host interface bus 4 for each cluster to be reproduced, and is input to the host interface 32. The reproduced command is transferred to the CPU-B 31 connected to the host interface 32 via the CPU-B bus 33.

When a playback command is supplied, the CPU-B 31 cooperates with the hard disk controller 30 to
The logical block address of the cluster read from the magnetic disk 5 is converted into a physical address inside the hard disk drive 3 (for example, disk surface number, track number, sector number, etc.). Then, the CPU-B 31 operates the servo control circuit 39 to move the magnetic head 38 to a target physical address. The magnetic head 38 reads the magnetization reversal pattern recorded here from the position corresponding to the target physical address on the magnetic disk 5.

Also, the CPU-B 31 reads the attribute of the cluster to be read (for example, whether the cluster to be read is an I picture,
(A picture or a B picture), and the information to that effect is stored in the temporary storage register 34 in the hard disk controller 30.

The magnetization reversal pattern read from the magnetic disk 5 by the magnetic head 38 is amplified by the reproduction amplifier 48 and then supplied to the reproduction channel circuit 49 in the channel IC 44.

The signal supplied to the reproduction channel circuit 49 in the channel IC 44 is
According to 9, the bit data is detected as a binary data sequence after synchronization, a decoding process that is the inverse of the channel coding performed at the time of recording is performed, and the data is reproduced as a data sector. This data sector may contain an error, but the hard disk controller 3
0 is transferred to the disk interface 43.

The operation timing of the disk interface 43 is controlled by the sequencer 37. When the sequencer 37 confirms that the magnetic head 38 is at the target position, the sequencer 37
The reproduction data is fetched from the reproduction channel circuit 49 of the channel IC 44 and supplied to the ECC circuit 41.

The ECC circuit 41 has the attribute (importance) of the cluster supplied from the disk interface 43.
, An error correction process is performed on each cluster with a different correction capability. That is, the ECC circuit 41
Identifies the supplied cluster attribute by referring to the temporary storage register 34 in which the information indicating the attribute of the cluster to be reproduced is stored, and switches its operation according to the identified attribute of the cluster to be reproduced. It has been made possible.

More specifically, for example, as shown in FIG. 4, the cluster to be reproduced is divided into three interleaves for each sector, and one interleave is used for each interleave.
When 4 bytes, a total of 42 bytes of error correction codes are added, a maximum of 7 By per interleave
Error correction up to te can be performed. However, when the ECC circuit 41 identifies that the supplied cluster is an I-picture of the GOP, the ECC circuit 41 corrects the error of this cluster up to, for example, 7 Bytes having the maximum correction capability. After making corrections,
If the supplied cluster is identified as a P-picture, the cluster is subjected to an error correction process equivalent to or lower than the error correction process performed on the cluster of the I-picture, and is supplied. If the cluster is identified as a B picture, P
An error correction process that is equivalent to or lower than the error correction process performed on the picture cluster is performed.

Generally, the ECC circuit 41 sets the error correction code amount to be applied to the I picture cluster to n1, the error correction code amount to be applied to the P picture cluster to n2, and the B picture When the code amount of the error correction applied to the cluster is n3 and the maximum value of the code amount of the error correction code added to each cluster is n _max , n _max
The correction capability is switched for each cluster so that error correction processing is performed so as to satisfy ≧ m1 ≧ m2 ≧ m3.

When error correction codes of different code amounts are added according to the attribute (importance) of the data to be recorded at the time of recording, the correction capability corresponding to the added code amount is provided for each cluster. Then, the ECC circuit 41 may perform an error correction process. For example, as in the example described above, at the time of recording, an I-picture cluster is added with an error correction code of 14 Bytes for each interleave, that is, a total of 42 Bytes, and a P-picture cluster is added with 10 Bytes for each interleave. Total 30By
te error correction code is added, and 7 bytes for each interlib for a B picture cluster, a total of 21 B
When the YTE error correction code is added, the ECC circuit 41 performs 7-byte error correction for each interleave for an I-picture cluster and 5 B for each interleave for a P-picture cluster.
Byte error correction may be performed, and for a B picture cluster, 3 Byte error correction may be performed for each interleave.

Data recording / reproducing apparatus 1 to which the present invention is applied
As described above, the ECC circuit 41 identifies the attribute of a cluster to be reproduced, and performs error correction with the maximum correction capability for a cluster of relatively low importance, such as a P picture or a B picture. Rather than performing the correction, the error correction is performed with the correction capability lowered, so that the time required for the error correction is reduced as a whole.

That is, when the error correction of the maximum correction capability is performed for all of the clusters to be reproduced, specifically, as shown in FIG. 8, a cluster of I pictures, a cluster of P pictures, and a B picture When 7 bytes of error correction processing with the maximum correction capability are performed for all clusters, the time required to perform error correction processing on 1 GOP data is the time allocated to 1 GOP data (0.5 seconds in the above example), and the real-time property may be impaired. On the other hand, in the data recording / reproducing apparatus 1 to which the present invention is applied, for example, a P picture cluster or a B picture cluster is not subjected to the maximum error correction processing error correction processing, and the correction capacity is not increased. Since the dropped error correction processing is performed, as shown in FIG. 9, the time required for the error correction processing for the entire data of one GOP is reduced, and the time allocated to the data of one GOP (0. (5 seconds).

In this case, in the P picture clusters and the B picture clusters, the data in which the error has occurred may be output without correction as much as the error correction processing with reduced correction capability is performed. There is. However, the data which is output as it is without correcting such errors is data of relatively low importance, and therefore the influence on the entire data is minimized.

Each cluster for which error correction has been performed by the ECC circuit 41 is temporarily stored in the buffer memory 36 as 512-byte logical data for each sector under the control of the bus controller 35. The data stored in the buffer memory 36 is stored in the host interface 3.
2. The data is sequentially transferred to the data processing device 2 via the host interface bus 4.

When the ECC circuit 41 outputs the data in which the error has occurred without correction, the error detection signal for notifying the data processing device 2 of the fact is sent from the ECC circuit 41 to the host computer. The data is supplied to the data processing device 2 via the host interface bus 4.

In the above description, the data constituting the AV data stream required to be real-time is recorded on the magnetic disk 5 in the hard disk drive 3 and the data constituting the AV data stream recorded on the magnetic disk 5 is recorded. Although the data recording / reproducing apparatus 1 configured to reproduce the data has been described as an example, the data recording / reproducing apparatus to which the present invention is applied is not limited to the above example.
In addition to the data stream, it may be configured to be able to record and reproduce other digital data such as a document file. Digital data such as document files do not require real-time performance,
That is, since it is required that data errors are extremely small, the data recording / reproducing apparatus is configured to be capable of recording / reproducing other digital data such as a document file in addition to the AV data stream. The AV
It is desirable that the contents of the processing be different between when handling the data constituting the data stream and when handling other digital data.

Hereinafter, the flow of the recording process and the flow of the reproducing process of the data recording / reproducing apparatus configured to be able to record and reproduce other digital data in addition to the AV data stream will be described. The data recording / reproducing apparatus has a basic configuration similar to that of the data recording / reproducing apparatus 1 described above, and performs the same processing as that of the data recording / reproducing apparatus 1 except for a process of adding an error correction code and a process of performing error correction. Therefore, the description of the same processing as that of the data recording / reproducing apparatus 1 is omitted here, and only the characteristic parts of the data recording / reproducing apparatus 1 will be described using the same reference numerals as those of the data recording / reproducing apparatus 1. .

When digital data is recorded on the magnetic disk 5 by the data recording / reproducing apparatus, a recording command issued from the data processing apparatus 2 via the host interface bus 4 is transmitted to the CP of the hard disk drive 3.
By being supplied to the U-B 31, it is recognized whether or not the data to be recorded is data constituting the AV data stream. Specifically, the recording command Comm shown in FIG.
From the and register, it is recognized whether the data to be recorded is data constituting the AV data stream.

When the data to be recorded is recognized as data constituting the AV data stream, the CPU-B 31 reads the cluster to be recorded from the Features register of the recording command in the same manner as in the data recording / reproducing apparatus 1 described above. (For example, whether the cluster to be recorded is an I picture, a P picture, or a B picture) is identified, and information to that effect is stored in the temporary storage register 34 in the hard disk controller 30.

Then, similarly to the data recording / reproducing apparatus 1 described above, the ECC circuit 41 uses the attribute (importance) of the cluster.
Error correction codes with different correction capabilities are added in accordance with. That is, when it is recognized that the data to be recorded is data constituting the AV data stream, the ECC circuit 4
1 refers to the temporary storage register 34 in which information indicating the attribute of the cluster to be recorded is stored, and identifies the attribute of the cluster to be recorded.
If this is an I picture, an error correction code having a high correction capability is added to this cluster, and if the cluster to be recorded is a P picture, this cluster is added to an I picture cluster. If an error correction code having a correction capability equal to or lower than the error correction code is added and the cluster to be recorded is a B picture, the error correction code added to the P picture cluster is added to this cluster. An error correction code having a correction capability equal to or lower than that of the error correction code is added.

On the other hand, when it is recognized that the data to be recorded is data other than the data constituting the AV data stream, the ECC circuit 41 applies a certain correction capability to each cluster constituting the data. Add an error correction code. In this case, from the viewpoint of data reliability, EC
It is desirable that the C circuit 41 add an error correction code having a large code amount to all the clusters to increase the error correction capability at the time of reproduction, but the code amount of the error correction code added to the data is not very large. If it is increased, the processing time becomes too long. Therefore, the ECC circuit 41
Is desirably configured such that an error correction code having the most desirable correction capability is added to each cluster constituting data to be recorded in view of a balance between the reliability of the data and the processing time.

According to this recording / reproducing apparatus, as described above, data to be recorded is recorded in AV
If the data is data constituting a data stream, an error correction code having a different correction capability is added to each cluster serving as a recording unit according to the attribute (importance) of the cluster, so that the data is reproduced. In some cases, for example, an error correction process is performed for a data block having a high importance such as an I picture over a long time, and an error correction processing is performed for data having a relatively low importance such as a B picture. The time for the correction process is reduced. As a result, the processing time as a whole is shortened, real-time properties are secured, and the occurrence of errors is efficiently suppressed, and the reliability of data is improved.

According to this recording / reproducing apparatus, as described above, when the data to be recorded is data other than the data constituting the AV data stream, an error correction code having a fixed correction capability is added. Therefore, when this data is reproduced, an error is effectively generated by performing error correction processing for all clusters over time or performing a retry operation as necessary. And the data reliability is greatly improved.

Next, when reproducing the digital data recorded on the magnetic disk 5 by the data recording / reproducing apparatus, a reproducing command issued from the data processing apparatus 2 via the host interface bus 4 is transmitted to the hard disk drive 3. By being supplied to CPU-B31,
It is recognized whether the data to be reproduced is data constituting the AV data stream. Specifically, it is recognized from the Command register of the playback command shown in FIG. 6 whether the data to be played back is the data constituting the AV data stream.

When it is recognized that the data to be reproduced is data constituting the AV data stream, the CPU-B 31 reads the cluster to be reproduced from the Features register of the reproduction command in the same manner as in the data recording / reproducing apparatus 1 described above. (For example, whether the cluster to be reproduced is an I picture, a P picture, or a B picture) is identified, and the information to that effect is stored in the temporary storage register 34 in the hard disk controller 30.

Then, similarly to the data recording / reproducing apparatus 1 described above, the ECC circuit 41 uses the attribute (importance) of the cluster.
The error correction processing is performed with different correction capabilities according to. That is, when it is recognized that the data to be reproduced is data constituting the AV data stream, the ECC circuit 41 refers to the temporary storage register 34 in which the information indicating the attribute of the cluster to be reproduced is stored, and reproduces the data. The attributes of the cluster are identified, for example, the cluster
If it is a picture, this cluster is subjected to an error correction process with a high correction capability, and the cluster to be reproduced is P
If the picture is a picture, this cluster is subjected to error correction processing with a correction capability equal to or lower than the error correction processing performed on the cluster of the I picture, and the cluster to be reproduced is a B picture. In some cases, this cluster is subjected to an error correction process with a correction capability equal to or lower than the error correction process performed on the P picture cluster.

On the other hand, when it is recognized that the data to be reproduced is data other than the data constituting the AV data stream, the ECC circuit 41 applies a certain correction capability to each cluster constituting the data. Perform error correction processing. In this case, from the viewpoint of data reliability, it is desirable that the ECC circuit 41 performs the error correction processing on all the clusters with the maximum correction capability. When the error correction processing is performed, there is a problem that the processing time becomes too long. Therefore, in this data recording / reproducing apparatus, in order to shorten the processing time without deteriorating the reliability of data, in a normal reproducing operation, the ECC circuit 41 does not perform the error correction processing with the maximum correction capability. When an error is detected in the corrected data, the same data is reproduced again by a retry operation. In this retry operation, the ECC circuit 41 performs an error correction process with the maximum correction capability. It is desirable to be configured.

According to this recording / reproducing apparatus, as described above, the data to be reproduced is AV
If the data constitutes a data stream, error correction processing is performed with a different correction capability depending on the attribute (importance) of each cluster as a reproduction unit. The error correction process takes time for data blocks of high importance, and the time of error correction processing for data of relatively low importance, such as B pictures, is reduced. In addition to realizing the real-time property by shortening the processing time, the occurrence of errors can be suppressed efficiently and the reliability of data can be improved.

According to this recording / reproducing apparatus, as described above, when the data to be reproduced is data other than the data constituting the AV data stream, the error correction processing is performed with a fixed correction capability. By performing error correction processing over time for all clusters or performing retry operations as necessary, the occurrence of errors is effectively suppressed, and the reliability of data is greatly reduced. Can be improved.

[0133]

According to the data recording apparatus of the present invention, when recording compressed image data on a recording medium,
For each data block serving as a recording unit, information indicating the importance of the data block is temporarily stored by the storage means, and based on the information indicating the importance of the data block temporarily stored in the storage means, an error correction code adding means is provided. However, since error correction codes with different correction capabilities are added to each data block, the overall processing time can be shortened, real-time data can be secured, and errors during reproduction can be reduced. Efficiency can be suppressed efficiently and data reliability can be improved.

In another data recording apparatus according to the present invention, when digital data is recorded on a recording medium, the digital data is compressed image data requiring real-time processing, or other digital data. If the digital data is determined to be compressed image data, information indicating the importance of the data block is stored in the storage means for each data block serving as a recording unit. Temporarily stored, based on the information indicating the importance of the data block temporarily stored in the storage unit, the error correction code adding unit adds an error correction code having a different correction capability for each data block,
On the other hand, when it is determined that the digital data is data other than the compressed image data, the error correction code adding means adds an error correction code having a fixed correction capability to the digital data. When recording compressed image data that requires real-time performance, the overall processing time is shortened to ensure real-time performance of the data, and the occurrence of errors during playback is efficiently suppressed, When recording data other than the compressed image data, the occurrence of errors during reproduction can be effectively suppressed, and the reliability of the data can be greatly improved.

In the data recording method according to the present invention, when recording compressed image data on a recording medium, information indicating the importance of the data block is temporarily stored for each data block serving as a recording unit. An error correction code having a different correction capability is added to each data block based on the information indicating the importance of the temporarily stored data block. Can be secured, and the occurrence of errors during reproduction can be efficiently suppressed, and the reliability of data can be improved.

According to another data recording method of the present invention, when digital data is recorded on a recording medium, the digital data is compressed image data requiring real-time processing or other data. If the digital data is determined to be compressed image data, information indicating the importance of the data block is temporarily stored for each data block serving as a recording unit, and the temporary storage is performed. When an error correction code having a different correction capability is added to each data block based on the information indicating the importance of the data block, and when the digital data is determined to be data other than the compressed image data. In order to add an error correction code with a fixed correction capability to this digital data, real-time performance is required. When recording compressed image data, the overall processing time is shortened to ensure data real-timeness, and the occurrence of errors during playback is efficiently suppressed to improve data reliability. When data other than the compressed image data is recorded, it is possible to effectively suppress the occurrence of errors at the time of reproduction and greatly improve the reliability of the data.

Further, in the data reproducing apparatus according to the present invention, when recording the compressed image data from the recording medium, information indicating the importance of the data block is stored by the storage means for each data block as a reproduction unit. Since the error correction means performs error correction with a different correction capability for each data block based on the information indicating the importance of the data block temporarily stored in the storage means, the overall The processing time can be shortened, real-time data can be secured, and the occurrence of errors can be suppressed efficiently, and the reliability of data can be improved.

In another data reproducing apparatus according to the present invention, when digital data is reproduced from a recording medium, the digital data is compressed image data requiring real-time processing, or other digital data. If the digital data is determined to be compressed image data, information indicating the importance of the data block is stored in the storage means for each data block serving as a reproduction unit. Based on the information indicating the importance of the data block temporarily stored in the storage unit, the error correction unit performs error correction with a different correction capability for each data block, while the digital data is compressed. If the digital data is determined to be data other than the image data, Since to perform error correction at a constant correction capability, when reproducing the image data compressed real time is required, while ensuring the real-time data to reduce the processing time as a whole,
Efficiently suppress errors and improve data reliability.When reproducing data other than compressed image data, effectively suppress errors and significantly improve data reliability. Can be improved.

Further, in the data reproducing method according to the present invention, when reproducing compressed image data from a recording medium, information indicating the importance of the data block is temporarily stored for each data block as a reproduction unit, Based on the information indicating the importance of the temporarily stored data blocks, error correction is performed with different correction capabilities for each data block, so that the overall processing time is shortened and data real-time performance is secured. In addition, the occurrence of errors can be efficiently suppressed, and the reliability of data can be improved.

According to another data reproducing method of the present invention, when reproducing digital data from a recording medium, the digital data is compressed image data requiring real-time processing or other data. If the digital data is determined to be compressed image data, information indicating the importance of the data block is temporarily stored for each data block serving as a reproduction unit, and the temporary storage is performed. Based on the information indicating the importance of the data block, the error correction is performed with a different correction capability for each data block. Error correction is performed on this digital data with a fixed correction capability. When reproducing the compressed image data, the overall processing time is shortened to ensure the real-timeness of the data, the occurrence is efficiently suppressed, the reliability of the data is improved, and data other than the compressed image data is used. When reproducing the data, the occurrence of errors can be effectively suppressed, and the reliability of the data can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of the configuration of a data recording / reproducing device to which the present invention is applied, and is a block diagram showing the inside of a data processing device in detail.

FIG. 2 is a diagram showing a firmware configuration of the data processing device.

FIG. 3 is a diagram showing a relationship between a GOP and a cluster which is a unit of recording and reproduction in the data recording / reproducing apparatus.

FIG. 4 is a diagram showing a sector format including an error correction code of data processed by a hard disk drive provided in the data recording / reproducing apparatus.

FIG. 5 is a diagram showing an example of a recording command used in the data recording / reproducing device.

FIG. 6 is a diagram showing an example of a reproduction command used in the data recording / reproducing device.

FIG. 7 is a diagram showing an example of the configuration of a data recording / reproducing apparatus to which the present invention is applied, and is a block diagram showing the inside of a hard disk drive in detail.

FIG. 8 is a diagram illustrating a relationship between an error correction process performed on each cluster constituting one GOP and a time required for the entire error correction process.

FIG. 9 shows a diagram of a data recording / reproducing apparatus to which the present invention is applied;
FIG. 7 is a diagram illustrating a relationship between an error correction process performed on each cluster constituting a GOP and a time required for the entire error correction process.

FIG. 10 is a block diagram showing a configuration example of a conventional hard disk drive.

[Explanation of symbols]

1 data recording / reproducing device, 2 data processing device, 3 hard disk drive, 5 magnetic disk, 6 CPU
-A, 30 hard disk controller, 31 CP
UB, 32 host interface, 34 temporary storage register, 36 buffer memory, 38 magnetic head, 41 ECC circuit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) G06F 12/16 320 G06F 12/16 320E H04N 5/78 H04N 5/78 Z 7/24 7/13 AF Terms (reference) 5B001 AA03 AA11 AB02 AC05 AD04 AE02 5B018 GA02 HA14 MA11 RA11 5C059 KK00 PP05 PP06 PP07 RF05 SS12 UA38

Claims (20)

[Claims] 1. A data recording device for recording compressed image data on a recording medium, wherein for each data block serving as a recording unit, storage means for temporarily storing information indicating the importance of the data block; An error correction code adding means for adding an error correction code having a different correction capability according to the importance of the data block for each data block serving as a recording unit based on the information stored in the storage means. Data recording device. 2. The apparatus according to claim 1, wherein said error correction code adding means adds an error correction code of a different code amount to each data block as a recording unit according to the importance of the data. Data recording device. 3. The image data is moving image data compressed by the MPEG encoding method, and the storage means stores, for each frame constituting the moving image,
Information indicating whether the frame is an I picture, a P picture, or a B picture is temporarily stored, and the error correction unit forms the moving image based on the information stored in the storage unit. Whether each frame is an I-picture, a P-picture,
2. The data recording apparatus according to claim 1, wherein an error correction code having a different correction capability is added depending on whether the picture is a picture. 4. The image data to which a magnetic disk is used as the recording medium and to which error correction codes having different correction capabilities are added by the error correction code adding means according to the importance of a data block serving as a recording unit. 2. The data recording apparatus according to claim 1, further comprising a data writing unit that writes data to said magnetic disk by a head. 5. A data recording apparatus for recording digital data on a recording medium, comprising: discriminating means for discriminating whether the digital data is compressed image data or other data; Storage means for temporarily storing, for each data block serving as a recording unit, information indicating the importance of the data block when it is determined that the digital data is compressed image data; Error correcting code adding means for adding a code, wherein the error correcting code adding means stores the digital data in the storage means when the digital data is determined to be compressed image data. Based on the information obtained, the data block that is the recording unit may have different corrections depending on the importance of the data block. Adds an error correction code capability, when the digital data is determined to be other data by the determination means, the data recording apparatus characterized by adding an error correction code of a fixed correction capability. 6. When recording compressed image data on a recording medium, information indicating the importance of the data block is temporarily stored for each data block serving as a recording unit, and the temporarily stored information is stored in the storage unit. A data recording method characterized by adding an error correction code having a different correction capability to each data block serving as a recording unit according to the importance of the data block. 7. An error correction code of a different code amount is added to each data block as a recording unit based on the temporarily stored information, according to the importance of the data. Data recording method described. 8. The image data is moving image data compressed by the MPEG encoding method, and for each frame constituting the moving image, the frame is
Information indicating whether the picture is a picture, a P picture, or a B picture is temporarily stored. Based on the temporarily stored information, for each frame constituting the moving image, the frame is an I picture. Whether it is a P picture, B
7. The data recording method according to claim 6, wherein an error correction code having a different correction capability is added depending on whether the picture is a picture. 9. A magnetic disk is used as the recording medium, and image data to which an error correction code having a different correction capability is added according to the importance of a data block serving as the recording unit is transferred to the magnetic disk by a magnetic head. 7. The data recording method according to claim 6, wherein writing is performed. 10. When recording digital data on a recording medium, it is determined whether the digital data is compressed image data or other data, and the digital data is stored in the compressed image data. If it is determined that there is, for each data block serving as a recording unit, information indicating the importance of the data block is temporarily stored, and based on the temporarily stored information, each data block serving as a recording unit is stored. Error correction code with a different correction capability according to the importance of the data block, and if the digital data is determined to be other data, an error correction code with a certain correction capability is added. A data recording method, characterized in that: 11. A data reproducing apparatus for reproducing image data compressed from a recording medium, wherein for each data block serving as a reproduction unit, storage means for temporarily storing information indicating the importance of the data block; A data reproducing apparatus comprising: an error correction unit that performs error correction with different correction capabilities for each data block serving as a reproduction unit based on the information stored in the data block according to the importance of the data block. 12. The data reproduction apparatus according to claim 11, wherein said error correction means decodes, for each data block serving as a reproduction unit, an error correction code having a different code amount according to the importance of the data. apparatus. 13. The image data is moving image data compressed by an MPEG encoding method, and the storage means stores, for each frame constituting the moving image,
Information indicating whether the frame is an I picture, a P picture, or a B picture is temporarily stored, and the error correction unit forms the moving image based on the information stored in the storage unit. Whether each frame is an I-picture, a P-picture,
The data reproducing apparatus according to claim 11, wherein error correction is performed with different correction capabilities depending on whether the picture is a picture. 14. A data reproducing apparatus according to claim 11, wherein a magnetic disk is used as said recording medium, and data reading means for reading image data written on said magnetic disk from said magnetic disk by a magnetic head is provided. apparatus. 15. A data reproducing apparatus for reproducing digital data from a recording medium, comprising: discriminating means for discriminating whether the digital data is compressed image data or other data; Storage means for temporarily storing, for each data block serving as a reproduction unit, information indicating the importance of the data block when it is determined that the data is compressed image data; When the digital data is determined to be compressed image data by the determination device, based on information stored in the storage device, Error correction is performed for each data block that is the unit of reproduction with different correction capabilities according to the importance of that data block. , When the digital data is determined to be other data by the determination means, the data reproduction apparatus characterized by performing error correction with a constant correction capability. 16. When reproducing compressed image data from a recording medium, information indicating the importance of the data block is temporarily stored for each data block as a reproduction unit, and based on the temporarily stored information. A data reproduction method comprising: performing error correction with a different correction capability for each data block serving as a reproduction unit according to the importance of the data block. 17. An apparatus according to claim 16, wherein for each data block serving as a reproduction unit, an error correction code having a different code amount is decoded in accordance with the importance of the data based on the temporarily stored information. Data reproduction method described. 18. The image data is moving image data compressed by an MPEG encoding method, and for each frame constituting the moving image, the frame is
Information indicating whether the picture is a picture, a P picture, or a B picture is temporarily stored. Based on the temporarily stored information, for each frame constituting the moving image, the frame is an I picture. Whether it is a P picture, B
17. The data reproducing method according to claim 16, wherein error correction is performed with different correction capabilities depending on whether the picture is a picture. 19. The data reproducing method according to claim 16, wherein a magnetic disk is used as the recording medium, and image data written on the magnetic disk is read from the magnetic disk by a magnetic head. 20. When reproducing digital data from a recording medium, it is determined whether the digital data is compressed image data or other data. If the digital data is compressed image data, When it is determined, for each data block serving as a playback unit, information indicating the importance of the data block is temporarily stored, and based on the temporarily stored information, for each data block serving as a playback unit, When error correction is performed with different correction capabilities according to the importance of the data block and the digital data is determined to be other data,
A data reproducing method characterized by performing error correction with a fixed correction capability.