JP2007122211A - Data recording system using semiconductor memory medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the deterioration of a writing speed by selectively recording data only in continuous regions when writing data in a flash memory. <P>SOLUTION: This data recording system detects the arrangement of the continuous empty clusters of a memory card 9 based on file management information in the memory card 9, and selectively records data only in a region where a plurality of or more empty clusters continuously exist in recording data. Furthermore, the data recording system varies the number of the continuous empty clusters in which data are recorded according to the recording rate of data. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a system for recording moving image data and / or audio data on a recording medium using a nonvolatile semiconductor memory such as a flash EEPROM.

  In recent years, various data such as text data, video data, and audio data created and edited by a personal computer (hereinafter abbreviated as “PC”), video data and audio data such as moving images and still images recorded with a digital camera, are flashed. Electronic devices that record on a memory card with a built-in memory (flash EEPROM) have become widespread. The flash memory is a non-volatile block erasable recording medium that is composed of a plurality of blocks and can electrically erase data recorded therein only in units of blocks. In the electronic device as described above, in order to facilitate data compatibility between devices and easy handling of data on a PC, a proposal to record data in a flash memory with the same format specifications as a PC data recording device (See, for example, Patent Document 1).

  Specifically, in the example of Patent Document 1, when a captured image is recorded in a flash memory in a digital still camera, it is managed with the same format specification as the data file recording format specification of the PC. Therefore, if a memory card, which is a data recording medium of the digital still camera, is set in an auxiliary recording device of a PC, data can be directly accessed from the PC. When data is managed in accordance with the data file recording format specification of the PC, the data is stored in file management information such as a file allocation table (hereinafter referred to as FAT), data recording start address or data in the logical memory space. Since it is managed by information such as the size, the recorded data can be easily searched, reproduced, copied, erased and the like, similar to the data file operation on the PC. At this time, the recorded data is naturally recorded and managed in logical recording units called clusters.

  Here, data management on the flash memory is performed using file management information such as FAT, but the file management information is logical management information to the last, and has a one-to-one correspondence with the physical configuration of the flash memory. There is no guarantee that it corresponds.

  For example, as shown in paragraphs “0004” to “0010” of Patent Document 2 and FIGS. 21 and 22, a logical recording unit (cluster) of data defined by the data file recording format specification, and flash memory There may be cases where the positions of electrical erasure units (blocks) do not match. In such a case, Patent Document 2 points out that the data recording speed decreases due to the necessity of saving even irrelevant data when updating or recording data.

When the data recording speed to the flash memory decreases, for example, in a device that needs to record a large amount of moving image data in real time, such as a video movie, it may be necessary to drop data or stop the recording operation. High nature.
JP-A-4-212582 (page 1-5, Fig. 1-4) JP 11-53248 A (page 3, FIG. 21, FIG. 22)

  Patent Document 2 points out the problem of a decrease in data recording speed by paying attention to the positions of logical recording units (clusters) of data and electrical erasing units (blocks) of flash memory. Another factor may be considered for the decrease in the data recording speed pointed out in paragraphs “0004” to “0010” and FIGS. In the example shown in FIG. 21 of Patent Document 2, data of a relatively small size close to the block size is recorded in the flash memory, and a part of the data is rewritten. Therefore, the data recording speed is decreasing.

  For example, in the example shown in FIG. 22 of Patent Document 2, in updating data for one cluster, data is read twice (once each in the Sa area and Sd area) and written four times (Sa, Occurs once in each of the Sb, Sc, and Sd regions. Of these reading and writing, reading and writing in the Sa and Sd areas are processes that are not directly related to data updating in the Sb and Sc areas, and are completely useless for updating the data in the Sb and Sc areas. It can be said processing. As the number of useless processes for such data writing increases, the data recording speed decreases. In the example of Patent Document 2, the size of data to be written is one cluster, and reading and writing of the Sa and Sd areas occur once each for the data writing of the one cluster, which is the cause of the decrease in the data recording speed. It has become.

  However, if the data size to be updated is not a single cluster but a plurality of clusters, the decrease in data recording speed is alleviated. For example, in FIG. 21 of Patent Document 2, if it is assumed that areas corresponding to Sb and Sc to be updated exist across 10 clusters, reading and writing of the Sa and Sd areas are performed for 10 clusters of data updates. It will occur once. That is, when data is recorded for 10 clusters, useless processing is performed once for reading and writing of the Sa and Sd areas. Even in the example of Patent Document 2 mentioned above, since the wasteful processing for data recording of one cluster is one time for reading and writing of the Sa and Sd areas, the larger the data size to be updated, the relatively, It can be said that useless processing converted per data writing for one cluster is reduced, that is, a decrease in data recording speed is alleviated.

  In view of this, the present invention is directed to a device that records video data and / or audio data using a recording device such as a flash memory as a recording medium, in order to avoid a decrease in data writing speed to the flash memory. An object of the present invention is to provide a data recording system in which data is selectively recorded only in a continuous area when writing is performed, and a decrease in writing speed can be reduced.

  In order to solve the problems described above, a data recording system using a semiconductor memory medium of the present invention is composed of electrically batch erasable blocks and is a logical recording defined by file management information. An apparatus for recording data in a memory means having a format specification for recording data in units, wherein the signal processing means performs processing on an input signal of at least one of a video signal and an audio signal, and the signal processing means Interface means for writing the processed data in the memory means, and detecting means for detecting the arrangement of the logical recording units capable of recording data in the memory means, When data is recorded in the memory means, two or more specific numbers continue in accordance with the detection result by the detection means. Wherein the recording data by selecting the logical recording units.

  In addition, the data recording system using the semiconductor memory medium of the present invention is composed of electrically erasable blocks, and has a format specification for recording data in a logical recording unit defined by file management information. An apparatus for recording data in a memory means having signal processing means for compressing at least one input signal of a video signal or an audio signal, and data compressed by the signal processing means, An interface means for writing to the memory means; a detecting means for detecting an arrangement of the logical recording units capable of recording data in the memory means; and the detection when recording the data in the memory means According to the detection result by the means, the logical recording unit that is continuous by a specific number of two or more is selected and data is selected. Control means for recording, and the two or more specific numbers are changed in accordance with a recording rate of at least one of the video signal and the audio signal after compression processing in the signal processing means. To do.

  The data recording system using the semiconductor memory medium of the present invention is characterized in that the specific number of two or more is set to be larger as the recording rate is higher.

  According to the present invention, in a device that records video data and / or audio data using a recording device such as a flash memory as a recording medium, data is stored in the flash memory in order to avoid a decrease in data writing speed to the flash memory. When data is written, data can be selectively recorded only in a continuous area, and a decrease in writing speed can be reduced. As a result, it is possible to reduce the possibility of missing data or stopping the recording operation that may occur when the data recording speed is reduced.

  According to the first aspect of the present invention, there is provided a memory means having a format specification for recording data in a logical recording unit defined by file management information, which is composed of electrically erasable blocks. An apparatus for recording data, wherein signal processing means for processing at least one input signal of a video signal or an audio signal, and data processed by the signal processing means are stored in the memory means. An interface means for writing; and a detecting means for detecting an arrangement of the logical recording units capable of recording data in the memory means, wherein the detection is performed when data is recorded in the memory means. The data is recorded by selecting the logical recording unit that is continuous by a specific number of two or more according to the detection result by the means. Thus, in a device that records video data and / or audio data using a recording device such as a flash memory as a recording medium, when data is written to the flash memory, data is selectively stored only in a continuous area. Can be recorded, and a decrease in writing speed can be reduced.

  According to a second aspect of the present invention, there is provided memory means having a format specification for recording data in a logical recording unit defined by file management information, which is composed of electrically erasable blocks. An apparatus for recording data, wherein a signal processing means for compressing at least one of an input signal of a video signal and an audio signal, and data compressed by the signal processing means are stored in the memory means. Interface means for writing, detection means for detecting the arrangement of the logical recording units capable of recording data in the memory means, and detection by the detection means when recording data in the memory means Control means for recording data by selecting the logical recording unit that is continuous by a specific number of two or more according to a result; and The two or more specific numbers are changed in accordance with the recording rate of at least one of the video signal and the audio signal after the compression processing in the signal processing means. In a device that records video data and / or audio data using a recording device such as the above, when data is written to the flash memory, the data is selectively recorded only in a continuous area, and the writing speed is reduced. The continuous area to be selected can be changed according to the recording rate of video data and / or audio data to be recorded.

  In the invention according to claim 3 of the present invention, the larger the recording rate, the larger the two or more specific numbers are set. Accordingly, the larger the recording rate, the larger the continuous area, the higher the speed. It is possible to further reduce the decrease.

(Embodiment 1)
FIG. 1 is a block diagram of a data recording system using a semiconductor memory medium according to the first embodiment of the present invention.

  In the figure, an optical system 1 is an optical system including at least one lens for forming a subject image on a solid-state image sensor 2. The solid-state image sensor 2 is an object imaged by the optical system 1. This is an image sensor that converts an elephant into an electric signal (video signal). For example, a charge coupled device (CCD) is used. The camera signal processing means 3 is means for performing known camera signal processing such as gain adjustment, noise removal, gamma correction, aperture processing, knee processing, and the like on the video signal obtained from the solid-state imaging device 2. Note that the video signal obtained via the solid-state imaging device 2 may be both a moving image and a still image. However, in the following description, the video signal is described as shooting a moving image, but is not limited thereto.

  Reference numeral 4 denotes a microphone for converting sound into an electric signal (sound signal). The sound signal is subjected to known sound signal processing such as removal of unnecessary noise and wind noise in the sound signal processing means 5. The digital signal processing means 6 is means for compressing and multiplexing the video signal and the audio signal that have passed through the camera signal processing means 3 and the audio signal processing means 5. In the present embodiment, the digital signal processing means 6 is capable of compressing video signals and audio signals at a plurality of different recording rates, and this recording rate is a user interface such as menu display or switch operation not shown. It can be switched by means, and is set in advance when recording a video signal and an audio signal.

  The card I / F unit 7 is a unit for writing and reading data to and from the memory card 9 electrically connected via the socket 8. The data compressed and multiplexed by the digital signal processing unit 6 is Data is written to the memory card 9 via the card I / F means 7.

  The memory card 9 is a detachable recording medium containing a semiconductor memory, for example, a flash memory (flash EEPROM), and is logically formatted with the FAT file system of MS-DOS (registered trademark). The continuous area detecting means 10 is means for detecting information related to an area where data can be continuously written in the memory card 9 from the data of the memory card 9 read out via the card I / F means 7. The system control unit 11 comprehensively controls the execution and stop of the compression processing of the video signal and the audio signal in the digital signal processing unit 6 and the start and stop of data writing to the memory card 9 by the card I / F unit 7. Further, data is recorded in a specific area on the memory card 9 according to the detection result of the continuous area detecting means 10.

  FIG. 2 is an example of a logical format specification previously applied to the memory card. In the first embodiment, as described above, only the necessary part of the format specification of the memory card 9 will be described below as the FAT file system generally used as the data file recording format specification of the PC.

  In FIG. 2, the blocks incorporated in the memory card 1 are divided into MBR (Master Boot Record) 21, boot sector 22, FAT I23, FAT II 24, directory 25, and data area 26 in order from the top area. These are collectively referred to as a management area 27. The MBR 21 stores information about each partition that can be provided with a bootstrap loader for reading an OS program and a memory card, and the boot sector 22 stores information about the partition. The FAT I23 is an area for storing a management table indicating the usage status of each cluster in the data area, and the FAT II24 is a backup of the FAT I23. The directory 25 stores information such as the file name, extension, and creation date / time of data existing under the root directory. The data area 26 is an area in which the main body of various data such as text data, video data, and audio data is recorded on the memory card 1.

  FIG. 3 is a diagram showing a cluster arrangement of the data area 26 of the memory card 1. In FIG. 3, each cluster is a unit for recording data in the flash memory, and data exceeding the cluster size is recorded across a plurality of clusters. In FIG. 3, the shaded clusters (clusters c to d, m to p) are clusters in which valid data has already been recorded, while other clusters have data recorded on the flash memory. These are assumed to be logically invalid (unnecessary) clusters (empty clusters). Whether the data of each cluster is valid or invalid is stored in FAT I23 and FAT II24.

  FIG. 4 is a diagram showing the relationship between the cluster arrangement of the data area 26 of the memory card 9 and the block arrangement of the flash memory. When the cluster boundary and the block boundary do not match as shown in FIG. 4, when the cluster data is updated, as described in detail in Cited Document 2, it is recorded in the flash memory block corresponding to the preceding and succeeding clusters. Data must be moved (saved). In such a case, as described in the cited document 2, a decrease in data recording speed may occur.

  In the data recording system using the semiconductor memory medium configured as described above, the memory card 9 has the format specification as shown in FIG. 3 and valid data has already been recorded in the clusters cd and mp. The case will be explained. First, it is assumed that the device user inserts the memory card 9 into the socket 8 shown in FIG. When the card I / F means 7 detects the attachment of the memory card 9, it notifies the continuous area detection means 10 and the system control means 11 of this. Upon receiving this notification, the continuous area detecting means 10 reads the information of the management area 27 recorded on the memory card 9 via the card I / F means 7 and uses the information in the management area 27 to identify the free cluster on the memory card 9. Ask for placement. Then, an area where data can be continuously recorded is detected based on the arrangement of free clusters. For example, in this embodiment, if it is determined that an area in which four clusters are continuously vacant is an area where data can be recorded, clusters e to h and clusters i to l can be recorded in FIG. It is judged as an area.

  When the continuous area detection unit 10 makes the above determination, the result is notified to the system control unit 11.

  When the device user instructs the recording start of the video signal and the audio signal by the recording ON / OFF means (not shown), the optical system 1, the solid-state imaging device 2, the camera signal processing means 3, the microphone 4, and the audio signal processing means 5 are used. The video signal and the audio signal obtained through the video signal are compressed in the digital signal processing means 6 and the multiplexed video signal and audio signal are subjected to the compression process, and the memory card is supplied via the card I / F means 7. 9, the system control unit 11 stores the data in the clusters e to h and the clusters i to l of the memory card 9 in which four clusters are continuously vacant based on the notification from the continuous region detection unit 10. Record.

  As described above, according to the first embodiment, when data is recorded, it is possible to reduce data recording speed reduction by selectively recording data in a certain number of consecutive free clusters. It is possible to reduce the possibility of missing data or stopping the recording operation that may occur due to a decrease in speed.

  In the present embodiment, the number of consecutive free clusters for data recording has been described as four. However, the present invention is not limited to this, and the recording rate of data recorded on the memory card 9, the recording speed of the memory card itself, etc. Needless to say, the number of consecutive free clusters for data recording may be set as appropriate.

(Embodiment 2)
Next, a data recording system using a semiconductor memory medium according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 5 is different from the data recording system using the semiconductor memory medium shown in FIG. 1 in that a region control unit 12 is newly added. Therefore, only differences from the first embodiment will be described below.

  In FIG. 5, the area control unit 12 detects the recording rate of the compression processing of the video signal and the audio signal performed by the digital signal processing unit 6, and the continuous area detection unit 10 detects the free space according to the recording rate. This is a means for changing the number of clusters.

  The operation of the data recording system using the semiconductor memory medium configured as described above will be described below.

  For example, it is assumed that the digital signal processing means 6 has two recording rates and can be switched by user interface means such as menu display and switch operation (not shown). For example, it is assumed that the recording rate can be switched between two recording rates of 10 Mbps (bit / sec) and 5 Mbps (bit / sec). Here, it is assumed that a recording rate of 10 Mbps is selected by user interface means such as menu display and switch operation (not shown). In this case, since it is necessary to record 10 Mbit data on the memory card 9 in a 1 sec period, it is necessary to record data on the memory card 9 at a higher speed than in the case where the recording rate is 5 Mbps. Therefore, when data is recorded on the memory card 9, the continuous area detecting means 10 detects, for example, eight consecutive free clusters (clusters e to l in FIG. 3) in order to realize faster data recording. The system control unit 11 is notified. If 5 Mbps is selected as the recording rate by user interface means such as menu display or switch operation (not shown), the continuous area detecting means 10 uses, for example, two consecutive free clusters (clusters a to. b, e to f, g to h, i to j, k to l) are detected and notified to the system control means 11.

  As a result, the video signal and the audio signal are compressed in the digital signal processing means 6, and the video signal and the audio signal after the compression processing are multiplexed and recorded in the memory card 9 via the card I / F means 7. However, the system control unit 11 records data in the clusters e to l of the memory card 9 based on the notification from the continuous area detection unit 10 when the recording rate is 10 Mbps, for example. When the recording rate is 5 Mbps, data is recorded in the clusters a to b, e to f, g to h, i to j, and k to l of the memory card 9.

  As described above, by changing the number of free clusters for data recording according to the data recording rate, if the recording rate is high, the data recording speed can be improved by taking many continuous free clusters. it can. As a result, it is possible to reduce the possibility of missing data or stopping the recording operation that may occur when the data recording speed decreases.

  In the present embodiment, the continuous number of empty clusters for data recording has been described as 2 and 8. However, the present invention is not limited to this. The recording rate of data to be recorded on the memory card 9 and the recording of the memory card itself are not limited thereto. Needless to say, the number of consecutive free clusters for data recording may be set as appropriate based on the speed or the like.

  In this embodiment, the two data recording rates have been described. However, the present invention is not limited to this, and the present invention is effective for devices having a larger number of recording rates.

  In all the embodiments of the present invention, the configuration in which the video signal and the audio signal are obtained using the solid-state imaging device 2 and the microphone 4 has been described. However, the present invention is not limited to this. For example, a TV tuner or an external video input unit is used. It is apparent that the present invention is effective even in a configuration in which video signals and audio signals input via TV broadcasting or other devices are compressed and recorded in the memory card 9.

  Further, in all the embodiments of the present invention, the description has been made based on a device that records a video signal and an audio signal. However, the present invention is not limited to this, and a device that records only a video signal or only an audio signal. Needless to say, the present invention is effective.

  In all the embodiments of the present invention, the configuration for compressing the video signal and the audio signal has been described. However, the present invention is not limited to this, and at least one of the video signal and the audio signal is written to the memory card 9 without being compressed. It goes without saying that the present invention is effective even in the configuration.

  Further, in all the embodiments of the present invention, the relationship between the cluster arrangement of the data area 26 of the memory card 9 and the block arrangement of the flash memory is such that the cluster boundary and the block boundary do not coincide as shown in FIG. Although explained, it is not limited to this. If the cluster boundary and the block boundary coincide with each other, data movement (evacuation) as detailed in the cited document 2 is unnecessary, and data recording as pointed out in the cited document 2 is performed. No speed reduction occurs. However, in general, in a recording medium using a flash memory or the like, the larger the data size written at one time, the faster the recording speed. For example, this is because of the physical characteristics of the memory and the reason that the number of write commands issued to the recording medium can be reduced by recording large data at once rather than recording small data many times. Therefore, the data recording methods described in all the embodiments of the present invention are effective even in cases other than those shown in FIG.

  In all the embodiments of the present invention, the logical format specification of the memory card 9 has been described as the FAT file system. However, the present invention is not limited to this, and the data recording area is not limited to this. It goes without saying that the present invention is effective as long as the format specification is such that a logical basic unit is provided to manage data.

  In all the embodiments of the present invention, the memory card 9 has been described as a detachable recording medium. However, the present invention is not limited to this, and the present invention is not limited thereto. Needless to say, the invention is effective.

  A data recording system for a semiconductor memory medium according to the present invention selectively records data only in a continuous area when writing data in order to avoid a decrease in data writing speed to the semiconductor memory medium. Can reduce the drop in data, and as a result, it can reduce the possibility of data loss and recording stoppage that can occur due to a decrease in data recording speed, and handles various types of information. Useful for various devices, equipment and systems that record data.

1 is a block diagram showing a configuration of a data recording system using a semiconductor memory medium in Embodiment 1 of the present invention. The conceptual diagram which shows the format specification of the memory card in Embodiment 1 Conceptual diagram showing a cluster arrangement of memory cards in the first embodiment Conceptual diagram showing the format specification of the memory card and the block configuration of the flash memory in the first embodiment FIG. 3 is a block diagram showing a configuration of a data recording system using a semiconductor memory medium in the second embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical system 2 Solid-state image sensor 3 Camera signal processing means 4 Microphone 5 Audio | voice signal processing means 6 Digital signal processing means 7 Card I / F means 8 Socket 9 Memory card 10 Continuous area detection means 11 System control means

Claims (3)

An apparatus for recording data in a memory means that is composed of electrically batch erasable blocks and has a format specification for recording data in logical recording units defined by file management information,
Signal processing means for processing the input signal of at least one of the video signal and the audio signal;
Interface means for writing the data processed by the signal processing means into the memory means;
Detecting means for detecting an arrangement of the logical recording units capable of recording data in the memory means;
With
When recording data in the memory means, the data is recorded by selecting the logical recording units that are continuous by a specific number of two or more according to the detection result by the detection means. A data recording system using a memory medium. An apparatus for recording data in a memory means that is composed of electrically batch erasable blocks and has a format specification for recording data in logical recording units defined by file management information,
Signal processing means for compressing at least one of the video signal and the audio signal;
Interface means for writing the data compressed by the signal processing means into the memory means;
Detecting means for detecting an arrangement of the logical recording units capable of recording data in the memory means;
When recording data in the memory means, according to the detection result by the detection means, a control means for selecting the logical recording unit that is continuous by a specific number of two or more and recording the data,
With
A data recording system using a semiconductor memory medium, wherein the two or more specific numbers are changed according to a recording rate of at least one of a video signal and an audio signal after compression processing in the signal processing means . 3. The data recording system using a semiconductor memory medium according to claim 2, wherein the two or more specific numbers are set to be larger as the recording rate is higher.

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