JP2000267904A - Data recorder and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely record large capacity data such as moving picture data in a recording medium at real time. SOLUTION: In the data recorder, data obtained by a digital camera or the like are converted into a digital signal by an A/D converter 1, the digital signal is compressed to code data by an encoder 2 and the code data are stored in an image memory 3. At the time of judging that data to be recorded in a recording medium 4 are data requested to be processed at real time by a signal outputted from a real time switch 6, a CPU 7 selects an area of a high transfer rate on the basis of the free area information of the medium 4 and preferentially records the data in the selected area. The area of the high transfer rate is an area having the large number of continuous unused clusters in the medium 4 and a block whose all clusters are unused. When data not necessitating real-time processing are inputted, the CPU 7 records the data in an area of a low transfer rate in the medium 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data recording apparatus and method, and more particularly, to a real-time recording of a large amount of data.

[0002]

2. Description of the Related Art Conventionally, a technique for recording moving image data, still image data or audio data on a recording medium (hard disk or flash memory) is well known. As a recording medium format, FAT (File Allocation Table) is generally used. In this method, a used area and an unused area in a data space of a recording medium are managed in a table format.
When new data needs to be written, the data is written to an unused area based on the management data.

[0003]

However, when recording and deletion of data having greatly different capacities are repeatedly performed, an unused area and a used area are mixed, and so-called fragmentation in which the unused area is intermittently occurs. Therefore, there is a problem that it is difficult to record a large amount of data such as moving image data in real time. That is, when fragmentation occurs, for example, in a hard disk, a seek time and a rotation waiting time for moving a head to an unused area intermittently exist, so that a transfer rate is reduced. In addition, in a flash memory, if a used cluster exists in a certain block, it is necessary to move the data obtained by combining the existing contents of the block and the data to be written to another empty block and record it, and the transfer rate is reduced. And the data cannot be recorded in real time.

Of course, in the case of small-capacity data, for example, still image data and audio data, it is possible to cope with a decrease in the transfer rate by temporarily storing the data in a buffer memory. It is difficult to store all large-capacity data in the buffer memory.
There is also a problem that a part of data is lost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the related art, and has as its object to provide an apparatus and a method capable of reliably recording a large amount of data such as moving image data on a recording medium in real time. Is to do.

[0006]

According to a first aspect of the present invention, there is provided an apparatus for recording data on a recording medium, comprising: storage means for storing free space information of the recording medium; Data is distinguished into real-time required data and real-time non-requested data, and based on the free space information, the real-time required data is stored in a relatively high transfer rate area of the recording medium. Control means for recording and recording the data not requiring the real-time property in a relatively low transfer rate area of the recording medium. By recording data requiring real-time properties in a high transfer rate area, real-time recording can be reliably executed. Note that the high transfer rate in the recording medium can be selected based on the free area information.

According to a second invention, in the first invention, the data requiring the real-time property is moving picture data, and the data not requiring the real-time property is still picture data or audio data. And This makes it possible to reliably record the moving image data in real time, and to prevent dropped frames.

In a third aspect based on the first and second aspects, the high transfer rate area is an area where the number of consecutive unused clusters is relatively large, and the low transfer rate area is: It is a region where the number of consecutive unused clusters is relatively small. In the case of a disk-type medium such as a hard disk, the higher the number of unused clusters, the higher the transfer rate because there is no seek time or rotation waiting time. Therefore, real-time recording becomes possible by recording data requiring real-time properties in an area where the number of unused clusters is relatively large.

In a fourth aspect based on the first and second aspects, the high transfer rate area is an unused block area, and the low transfer rate area is a used block area. Features. On a recording medium such as a flash memory, which has a limited number of rewrites, unless all clusters in a block are unused, an operation is performed to move to another empty block so that rewrite does not occur intensively in a certain block. The transfer rate decreases. on the other hand,
When data is recorded in an unused block, that is, a block in which all clusters in the block are unused, such a movement is not necessary, and high-speed recording can be performed. Therefore, real-time recording becomes possible by recording data requiring real-time properties in unused blocks.

In a fifth aspect based on the first and second aspects, the control means sequentially records the data requiring the real-time property from an area of the recording medium having a large number of unused cluster continuations. The data that does not require the real-time property is sequentially recorded from an area of the recording medium where the number of unused cluster continuations is small. Real-time recording becomes possible by sequentially allocating and recording data requiring real-time properties from an area having a high transfer rate.

In a sixth aspect based on the first and second aspects, the control means sequentially records the data requiring the real-time property from an unused block area, and stores the data requiring no real-time property. Are sequentially recorded from the used block of the recording medium. According to the present invention as well, real-time recording becomes possible by sequentially allocating and recording data requiring real-time properties from an area having a high transfer rate.

A seventh aspect of the present invention is a method of recording data on a recording medium, wherein the data for which real-time recording is required is sequentially recorded from an area of the recording medium where the number of unused cluster continuations is large. Data that is not required to be recorded is sequentially recorded from an area of the recording medium where the number of unused cluster continuations is small.

An eighth invention is a method for recording data on a recording medium, wherein data requiring real-time recording is preferentially recorded in an unused block of the recording medium, and real-time recording is not required. The data not to be recorded is preferentially recorded in the used block of the recording medium.

In a ninth aspect based on the seventh and eighth aspects, the data for which real-time recording is required is moving image data, and the data for which real-time recording is not required are still image data or audio data. It is characterized by the following.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of this embodiment. The data recording device includes an A / D 1, an encoder 2, an image memory 3, a free area storage unit 5, a real-time switch 6, and a CPU 7. When the data recording device is applied to, for example, a digital camera or a digital movie, an optical system (not shown) such as a CCD sensor is also included.

Data obtained by a CCD sensor or the like is A /
The digital data is converted by D1 and supplied to the encoder 2.
In the encoder 2, the input data is compression-encoded and stored in the image memory 3. The CPU 7 reads out the management data indicating the free space information recorded on the recording medium 4 and stores it in the free space storage unit 5, and when recording the data stored in the image memory 3 on the recording medium 4, It is determined whether or not the recording data requires real-time processing. Whether the real-time property is required is determined based on a signal from the real-time switch 6. The real-time switch 6 can be constituted by, for example, a mode switch for a moving image mode / still image mode in the case of a digital camera. When set, it can be determined that the data does not require real-time properties. After discriminating whether the data to be recorded on the recording medium 4 is data requiring real-time property or not, the data is stored in a predetermined area of the recording medium 4 based on the free area information stored in the free area storage unit 5. Record each data. Specifically, data requiring real-time property is recorded in a high transfer rate area of the recording medium 4 to realize real-time recording, and data not requiring real-time property is recorded in a low transfer rate area. Specific contents of the high transfer rate area and the low transfer rate area will be described later.

In FIG. 2, the CPU 7 reads out management data recorded on the recording medium 4 and
An example of the usage status stored in the storage area is shown. In the figure, each cluster goes from the upper left to the lower right, and sequentially from the first cluster to the last cluster, 0, 1, 2,.
It is numbered nine. Clusters with diagonal lines are unused clusters, and other clusters are used clusters (data recorded clusters). For example, the 0th cluster to the 2nd cluster are used clusters, the 3rd cluster is an unused cluster, and the 4th cluster is a used cluster. In the upper stage, fragmentation has occurred. The CPU 7 determines which area of the recording medium 4 can achieve a high transfer rate based on such usage data, and records moving image data that requires real-time properties.

FIG. 3 shows a transfer rate order table created by the CPU 7 based on the free area information stored in the free area storage unit 5 when the recording medium 4 is a hard disk. In the figure, the left column shows the top cluster number, and the right column shows the number of unused clusters (the number of unused cluster continuations) that continue from the top cluster number.
For example, the first row is (3, 1), which indicates that there is only one unused cluster from the third cluster. The second row is (10, 1), which indicates that there is only one unused cluster from the tenth cluster. Further, the third row is (5, 2), which indicates that two unused clusters continue from the fifth cluster. The sixth row is (33, 27), which indicates that 27 unused clusters continue from the 33rd cluster.

As can be seen from FIG. 3, in this table, the smaller the number of consecutive unused clusters, the higher the rank. The larger the number of unused clusters, the lower the rank. As the number of unused cluster continuations is larger, the seek time of the head and the rotation waiting time are eliminated, so that the transfer rate is increased. Therefore, in the table of FIG. 3, the transfer rate decreases as going to the higher position, and the transfer rate increases as going to the lower position.

Therefore, based on the signal from the real-time switch 6, the CPU 7 starts from the bottom of the table shown in FIG. The recording area is preferentially allocated. On the other hand, if the data to be recorded is data that does not require real-time properties, for example, still image data, the recording area is preferentially allocated from the top of the list in the table shown in FIG. As a result, data requiring a real-time property is recorded in a high transfer rate area and can be recorded in a real-time manner, and data not requiring a real-time property is recorded in a low transfer rate area. It is conceivable that data that does not require real-time properties is temporarily stored in the buffer memory and recorded on the recording medium 4.

FIG. 4 shows a processing flowchart of the CPU 7 when the recording medium 4 is a hard disk. First, the CPU 7 reads management information from a file system on the recording medium 4 (S101). This management information may be in the bitmap format or the table format described above. Then, the read management information is stored in the free area storage unit 5, and a table shown in FIG. 3 (hereinafter referred to as a free sector list) is created (S).
102). After the empty sector list is created, the process waits until the shooting starts (S103), and after the shooting starts, waits until one or more frames of data are transferred to the image memory 3 (S104).

After one or more frames of data are stored in the image memory 3, the CPU 7 determines whether or not the real-time switch 6 is turned on (S105). As described above, this switch can be configured as a moving image mode / still image mode switching switch. When the user sets the moving image mode, it is determined that the real time switch has been turned on. When the real-time switch is turned on, the CPU 7 secures clusters for frames held in the image memory 3 from below (lower) the empty sector list created in S102 (S10).
6) The image data is transferred to the secured cluster and recorded (S107). If clusters for frames held in the image memory cannot be secured in S106, recording is performed in the next control cycle. After recording the data stored in the image memory 3 on the recording medium 4, the free sector list (free cluster list) is changed so that the used cluster is deleted (S108).

On the other hand, after one or more frames of data are transferred to the image memory 3, if the real-time switch 6 is not turned on, for example, if the user sets the still image mode of the digital camera, the CPU 7 proceeds to S102. Image memory 3 from the top (upper) of the created free sector list
(S1).
09), the data is recorded by transferring the image data to the secured cluster (S110). And S10
The free sector list is changed so that the used cluster is deleted in the same manner as in step 8 (S111).

The above processing is repeated until photographing is completed and unrecorded data no longer exists (S112), and all data is recorded on the recording medium 4. As a result, data requiring real-time characteristics, for example, moving image data, is preferentially allocated to the high transfer rate area and recorded in real time, and still image data, etc., which does not require real time properties, are preferentially allocated to the low transfer rate area. Recorded. After recording all the data, the CPU 7 changes the management information and records it on the recording medium 4 (S11).
3).

FIG. 5 shows a table created by the CPU 7 when the recording medium 4 is a flash memory. Since the flash memory has a limit on the number of times of rewriting, when writing data to a block in which data is already recorded as described above, the contents of the block should be written in order to level the number of times of writing between blocks. Recording is performed by moving the combined data to another empty block. Therefore, when writing is performed on a block in which data is already recorded, the transfer rate is lower than when writing is performed on a block in which no data is recorded. CPU7
Creates a table in order of transfer rate as shown in FIG. 5 in view of such circumstances.

In FIG. 5, the first to third rows are shown in FIG.
Is the same as the hard disk shown in
The row is (33, 3). This means that, in FIG. 2, when one block is composed of four clusters, the 33rd cluster is composed of four clusters of a 32nd cluster, a 33rd cluster, a 34th cluster, and a 35th cluster. Since all clusters in this block are not unused and the 32nd cluster is already used, writing data to this block has a higher transfer rate than writing to unused blocks. Is at the top of the table because it decreases. FIG.
The sixth row of the table is (16, 4), which is located lower than (33, 3) in the fourth row. This is because the sixteenth cluster is the sixteenth cluster, the seventeenth cluster, and the 1
This is a part of a block composed of four clusters of the eight clusters and the nineteenth cluster. Since all clusters in this block are unused, when writing data to this block (33, 3) Means that data can be written at a higher transfer rate than when data is written to the block indicated by.

As described above, the CPU 7 creates a table so that blocks in which all the constituent clusters are unused (unused blocks) are positioned at a lower level. of course,
Between unused blocks, the larger the number of consecutive unused blocks, the lower the position in the table. Thereby, in the table of FIG. 5, the transfer rate decreases as going to the higher order, and the transfer rate increases as going to the lower order.

FIG. 6 shows a processing flowchart of the CPU 7 when the recording medium 4 is a flash memory. First, the CPU 7 reads management information from the file system on the recording medium 4 (S201). Then, the read management information is stored in the free area storage unit 5, and a table shown in FIG. 5 (hereinafter also referred to as a free sector list) is created from the stored management information (S).
202). Then, it waits until the start of shooting (S203),
It is determined whether the real-time switch 6 is turned on (S204).

When the real-time switch 6 is turned on, for example, when the user sets the mode of the digital camera to the moving image mode, it waits until one or more blocks of data are stored in the image memory 3 (S205). After one or more blocks of data are stored, a cluster of one block is preferentially secured from the bottom (lower) of the list created in S202 (S206). Then, the image data is transferred to the secured cluster and recorded (S207). After recording the data in the unused cluster, the free sector list created in S202 is changed so that the used cluster is deleted (S208).

On the other hand, when the real-time switch 6 is not turned on, for example, when the user sets the mode of the digital camera to the still image mode, the CPU 7 waits until one or more frames of data are stored in the image memory 3. (S209) The data of one frame or more is stored in the image memory 3
After that, clusters for the frames held in the image memory 3 are preferentially secured from the top (upper) of the list created in S202 (S210). Then, the data is recorded on the recording medium 4 by transferring the image data to the secured cluster (S211). After recording the data, the free sector list created in S202 is changed (S212).

The above processing is performed on all data.
After recording all the data obtained by photographing on the recording medium 4, the management information is recreated and recorded on the recording medium 4 (S213, S214). This also enables real-time recording by allocating data requiring real-time performance to a relatively high transfer rate area, and recording data that does not need to be allocated to a relatively low transfer rate area.

As described above, in this embodiment, an area where a high transfer rate can be obtained is extracted based on the free area information of the recording medium 4, and data requiring real-time properties is preferentially assigned. Real-time recording can be realized.

In the present embodiment, a hard disk (including a card) or a flash memory has been described as an example of a recording medium, but the present invention is not limited to this and can be applied to any recording medium.

In the present embodiment, moving image data is required as data requiring real-time properties, and still image data is required as data not requiring real-time properties. However, the present invention is not limited to these. . For example, if only audio data is acquired (video data with audio data is included in "video data"),
The audio data can be processed as data that does not require real-time properties.

[0036]

According to the present invention, large-capacity data such as moving image data is preferentially assigned to the high transfer rate area, so that real-time recording can be reliably performed.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram showing a usage state of a recording medium.

FIG. 3 is an explanatory diagram of a transfer rate order table when a recording medium is a hard disk card.

FIG. 4 is a CP when a recording medium is a hard disk.
6 is a processing flowchart of U.

FIG. 5 is an explanatory diagram of a transfer rate order table when a recording medium is a flash memory.

FIG. 6 shows C when the recording medium is a flash memory.
It is a processing flowchart of PU.

[Explanation of symbols]

1 A / D, 2 encoders, 3 image memories, 4 recording media, 5 free area storage section, 6 real time switch, 7 CPU.

Continued on front page F term (reference) 5B082 AA13 CA01 CA03 CA08 5C052 AA03 AA17 AB02 CC11 DD04 EE02 5C053 FA07 FA23 GA11 GA16 GA20 GB11 GB17 GB21 KA03 KA24 KA25 KA30 LA02 5D044 AB07 AB08 DE02 DE03 DE14 DE48 EF06

Claims (9)

[Claims] 1. An apparatus for recording data on a recording medium, comprising: storage means for storing free area information of the recording medium; and distinguishing the data into data requiring real-time properties and data not requiring real-time properties. Then, based on the free space information, the real-time required data is recorded in a relatively high transfer rate area of the recording medium, and the real-time non-required data is relatively recorded on the recording medium. A data recording device, comprising: control means for recording data in a low transfer rate area. 2. The data recording apparatus according to claim 1, wherein the data requiring the real-time property is moving picture data, and the data not requiring the real-time property is still picture data or audio data. apparatus. 3. The apparatus according to claim 1, wherein the high transfer rate area is an area in which the number of consecutive unused clusters is relatively large, and the low transfer rate area is:
A data recording device characterized in that the number of consecutive unused clusters is a relatively small area. 4. The apparatus according to claim 1, wherein the high transfer rate area is an unused block area, and the low transfer rate area is a used block area. Data recording device. 5. The apparatus according to claim 1, wherein the control unit sequentially records the data requiring the real-time property from an area of the recording medium where the number of consecutive unused clusters is large, A data recording apparatus for sequentially recording data that does not require the real-time property from an area of the recording medium where the number of unused clusters is small. 6. The apparatus according to claim 1, wherein the control unit sequentially records the data requiring the real-time property from an unused block area, and stores the data not requiring the real-time property. A data recording apparatus which records sequentially from the used blocks of the recording medium. 7. A method for recording data on a recording medium, wherein data for which real-time recording is required is sequentially recorded from an area of the recording medium where the number of unused clusters is large, and data for which real-time recording is not required. Is a method for recording data sequentially from an area of the recording medium where the number of unused clusters is small. 8. A method for recording data on a recording medium, wherein data requiring real-time recording is preferentially recorded in an unused block of the recording medium, and data not requiring real-time recording is recorded. A data recording method characterized by recording preferentially on a used block of a medium. 9. The method according to claim 7, wherein the data for which real-time recording is required is moving image data, and the data for which real-time recording is not required is still image data or audio data. A data recording method, comprising: