Abstract:
A data reproducing device disclosed herein comprises: a disk analysis executor which performs a disk analysis of analyzing a file and directory structure of a record medium; a detection judgment section which judges whether or not a predetermined number of files and/or a predetermined number of directories including a file is detected by the disk analysis executor; and a reproduction starter which suspends the disk analysis and starts reproduction of data of the detected file when the detection judgment section judges that the predetermined number of files and/or the predetermined number of directories including the file is detected.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
         [0001]    This application claims benefit of priority under 35 U.S.C.§119 to Japanese Patent Application No. 2003-141635, filed on May 20, 2003, the entire contents of which are incorporated by reference herein.  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to a data reproducing device and a control method of the data reproducing device, and particularly relates to a data reproducing device which realizes a reduction in the time required before file reproduction is started and a control method of the data reproducing device which realizes the same.  
           [0004]    2. Related Background Art  
           [0005]    [0005]FIG. 7 is a flowchart explaining the contents of a related disk analysis process in a data reproducing device such as a CD-MP3 for reproducing data. As shown in FIG. 7, in the related disk analysis process, the data reproducing device first performs a disk analysis of analyzing a file and directory structure of a set disk (step S 2 ).  
           [0006]    The data reproducing device then judges whether or not all files in the set disk are detected (step  4 ). Thereafter, it stores information on the detected files (media files) in a file table.  
           [0007]    When all the files are not detected (step S 4 : No), the disk analysis process is continued (step S 2 ). On the other hand, when all the files are detected (step S 4 : Yes), the disk analysis is completed, and reproduction of the files is started (step S 6 ).  
           [0008]    In the related data reproducing device shown in FIG. 7, one of the greatest number of improvement requests from end users is a request for a reduction in the analysis time from the recognition of a disk to the start of reproduction. This is because in a common audio CD, reproduction is started in a few seconds after a disk is recognized, whereas in the data reproducing device such as the CD-MP3, an analysis is performed using a limited memory, and hence a few tens of seconds (a few minutes depending on disk structure) are needed after a disk is recognized.  
           [0009]    This becomes more pronounced when the numbers of directories and files stored in one CD are large since the disk structure becomes more complicated.  
         SUMMARY OF THE INVENTION  
         [0010]    In order to accomplish the aforementioned and other objects, according to one aspect of the present invention, a data reproducing device, comprises:  
           [0011]    a disk analysis executor which performs a disk analysis of analyzing a file and directory structure of a record medium;  
           [0012]    a detection judgment section which judges whether or not a predetermined number of files and/or a predetermined number of directories including a file is detected by the disk analysis executor; and  
           [0013]    a reproduction starter which suspends the disk analysis and starts reproduction of data of the detected file when the detection judgment section judges that the predetermined number of files and/or the predetermined number of directories including the file is detected.  
           [0014]    According to another aspect of the present invention, a control method of a data reproducing device, comprises:  
           [0015]    performing a disk analysis of analyzing a file and directory structure of a record medium;  
           [0016]    judging whether or not a predetermined number of files and/or a predetermined number of directories including a file is detected; and  
           [0017]    suspending the disk analysis and starting reproduction of data of the detected file when it is judged that the predetermined number of files and/or the predetermined number of directories including the file is detected. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    [0018]FIG. 1 is a block diagram showing an example of the configuration of a data reproducing device according to a first embodiment;  
         [0019]    [0019]FIG. 2 is a diagram showing an example of the structure of directories and files stored in a CD;  
         [0020]    [0020]FIG. 3 is a diagram showing an example of the structure of a file table according to the first embodiment;  
         [0021]    [0021]FIG. 4 is a diagram showing an example of the configuration of a data buffer according to the first embodiment;  
         [0022]    [0022]FIG. 5 is a flowchart explaining the contents of a disk analysis process according to the first embodiment;  
         [0023]    [0023]FIG. 6 is a flowchart explaining the contents of a disk analysis process according to a second embodiment; and  
         [0024]    [0024]FIG. 7 is a flowchart explaining the contents of a related disk analysis process. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
     First Embodiment  
       [0025]    As described above, in a related data reproducing device, file reproduction is started after a disk analysis of a set disk is all completed, but in this embodiment, at a point in time when any number of files (the number is an arbitrary number equal to or more than one) are detected during a disk analysis, the disk analysis is temporarily suspended and reproduction of the file or files is started, whereby the time between the setting of the disk and the start of reproduction is reduced.  
         [0026]    File reproduction is performed while reading to and from a buffer memory is being performed, whereby an idle time during which access to the disk is unnecessary occurs. The disk analysis is continued using this idle time, which makes it possible to perform the disk analysis while performing the reproduction, so that the suspended disk analysis can be performed to the last. At this time, by determining the number of files at any number when files to be reproduced are designated, the reproduction can be prevented from being stopped during the analysis. A more detailed explanation will be given below.  
         [0027]    [0027]FIG. 1 is a block diagram explaining the configuration of a compressed data reproducing device according to this embodiment. In FIG. 1, data compressed according to MP3 is stored in a CD (compact disc)  10 , the MP3 is one of MPEG audio CD data compression standards. This CD  10  is rotated by a motor  14  which is driven by a driver  12 . The driver  12  is controlled by a CD servo  16  and rotates the CD  10  at a constant angular speed.  
         [0028]    A reproduction signal obtained corresponding to a pit row on a track with the rotation of the CD 10  is supplied from a pickup  20  to an RF amplifier  22 , amplified, and supplied to the CD servo  16 . The CD servo  16  is controlled by a microcomputer (MCU)  24 , and a bit stream converted to a digital signal is generated in the CD servo  16 .  
         [0029]    The bit stream generated in the CD servo  16  is supplied to a ROM decoder  26 . The ROM decoder  26  decodes this bit stream and acquires MP3 data compressed by the MP3. This MP3 data is stored in a data buffer  30 , read from the data buffer  30  in sequence, and supplied to an MP3 decoder  32 . The MP3 decoder  32  decodes this MP3 data to generate PCM audio data and outputs the PCM audio data to a digital-analog converter  34 . Both the ROM decoder  26  and the MP3 decoder are also controlled by the microcomputer  24 . Moreover, in this embodiment, the ROM decoder  26 , the data buffer  30 , and the MP3 decoder  32  are formed in one semiconductor chip  50 . Further, the ROM decoder  26  according to this embodiment contains a controller, which controls various processes in disk analysis.  
         [0030]    The digital-analog converter  34  to which the PCM audio data is inputted converts the PCM audio data to an analog signal and outputs the analog signal to an amplifier  36 . The analog signal amplified by the amplifier  36  is reproduced by a speaker  38  to obtain a reproduced sound.  
         [0031]    [0031]FIG. 2 is a diagram showing an example of the disk structure of the CD  10  in this embodiment. In the example in FIG. 2, a &lt;root&gt; directory is located in a highest level, and a &lt;POPS&gt; directory, a &lt;ROCK&gt; directory, and a file aaa.mp3 are located in a second level.  
         [0032]    In a third level, an &lt;AYU&gt; directory and an &lt;UTADA&gt; directory are located in a level under the &lt;POPS&gt; directory. In the third level, a &lt;BZ&gt; directory, an &lt;EMPTY&gt; directory, a &lt;HIDE&gt; directory, a file bbb.mp3, and a file ccc.mp 3  are located in a level under the &lt;ROCK&gt; directory.  
         [0033]    In a fourth level, a file ddd.mp3 and a file eee.mp3 are located in a level under the &lt;AYU&gt; directory. In the fourth level, a file fff.mp3 and a file ggg.mp3 are located in a level under the &lt;UTADA&gt; directory. In the fourth level, a file hhh.mp3 is located in a level under the &lt;BZ&gt; directory, and a file iii.mp3 is located in a level under the &lt;HIDE&gt; directory.  
         [0034]    [0034]FIG. 3 is a diagram showing an example of a file table FTB generated by performing a disk analysis of the CD  10  having the disk structure shown in FIG. 2. In this case, as shown in FIG. 3, regarding the order of tracks, a file in the higher level is reproduced first, and tracks in the same level are reproduced in alphabetical order. This complies with the ISO 9660.  
         [0035]    Moreover, in this embodiment, in the file table FTB, a start address and an end address of the data stored on the CD  10  for each file are stored on a file-by-file basis.  
         [0036]    As described above, in a related data reproducing device, after a disk analysis of one CD  10  which is set in the data reproducing device is completed, that is, after generating the file table FTB in FIG. 3 is finished, reproduction of respective files is started in order from the first one. On the other hand, in this embodiment, at a point in time when a predetermined number (for example, two) of files are detected and information thereon is stored in the file table FTB, reproduction is started from the first music. The disk analysis is restarted through the use of the idle time of reproduction to successively create the file table FTB.  
         [0037]    [0037]FIG. 4 is a diagram explaining the configuration of a memory area of the data buffer  30  according to this embodiment. In the example in FIG. 4, a disk analysis area AR 1 , a reproduction area AR 2 , and a file table area AR 3  are formed in the data buffer  30 .  
         [0038]    The disk analysis area AR 1  is an area in which the ROM decoder  26  holds data necessary for the disk analysis of the CD  10 . The reproduction area AR 2  is an area in which the MP3 data for reproduction is stored. The MP3 data is read in sequence from this reproduction area AR 2  and outputted to the MP3 decoder  32 . The file table area AR 3  is an area in which the file table FTB shown in FIG. 3 is formed and stored.  
         [0039]    [0039]FIG. 5 is a flowchart explaining the contents of a disk analysis process executed by the controller contained in the ROM decoder  26  according to this embodiment. The disk analysis shown in FIG. 5 is a process started when a user sets the new CD  10  in the data reproducing device, or the like.  
         [0040]    In this disk analysis process, first, the ROM decoder  26  performs a disk analysis of the CD 10  (step S 10 ). More specifically, the ROM decoder  26  reads data necessary for the disk analysis from the CD  10  and stores the data in the disk analysis area AR 1  of the data buffer  30 . Then, directory structure specification and file detections are performed. Information on the detected file (media file) is stored in the aforementioned file table FTB.  
         [0041]    While performing this disk analysis process, the ROM decoder  26  judges whether or not a predetermined number of files are detected (step S 12 ). This predetermined number may be set in design time in advance or may be settable at the discretion of a user. In this embodiment, the predetermined number is set, for example, at two.  
         [0042]    When the predetermined number of files are not detected (step S 12 : No), the disk analysis process is continued (step S 10 ). On the other hand, when the predetermined number of files are detected (step S 12 : Yes), the disk analysis is temporarily suspended (step S 14 ). In the example in FIG. 2 and FIG. 3 in this embodiment, at this suspended point in time, information on two files of the file aaa.mp3 and the file bbb.mp3 is stored in the file table FTB.  
         [0043]    Thereafter, the ROM decoder  26  starts reproduction of analyzed files (step S 16 ). More specifically, the ROM decoder  26  reads data (bit stream) from a start address of the file aaa.mp3 which is the first music and stores it as MP3 data in the reproduction area AR 2  of the data buffer  30 . Generally, the size of the reproduction area AR 2  is smaller than the data size of one track, and hence only data of an amount storable in the reproduction area AR 2  is read from the CD  10 . Then, the ROM decoder  26  reads the MP3 data in sequence and sends it to the MP3 decoder to reproduce it, and, for example, at a point in time when the amount of not-yet-reproduced MP3 data becomes smaller than 20% of the size of the reproduction area AR 2 , the ROM decoder  26  starts to read a continuation of the data from the CD  10 .  
         [0044]    Accordingly, while the MP3 data is read from the reproduction area AR 2  and being reproduced, it is unnecessary to access the CD  10 . Hence, in this embodiment, a continuation of the disk analysis is performed using this idle time (step S 18 ). If the amount of the not-yet-reproduced data in the reproduction area AR 2  lessens while the disk analysis is being performed, the disk analysis is temporarily suspended, and a continuation of the data for reproduction is read from the CD  10 .  
         [0045]    Then, this process is repeated until the disk analysis of one CD  10  is completed, so that the file table FTB shown in FIG. 3 is finished. At a point in time when the file table FTB concerning one CD  10  is finished, this disk analysis process ends. Consequently, the ROM decoder  26  can be engaged exclusively in the process for file reproduction.  
         [0046]    The amount of the not-yet-reproduced data in the reproduction area AR 2  at which the disk analysis is suspended and additional data is read may be set in design time in advance or may be settable at the discretion of the user. When the amount of nor-yet-reproduced MP3 data is set at a large amount (for example, when the amount is set at 60% of the reproduction area AR 2 ), the possibility that the reproduced track is interrupted halfway can be reduced. On the other hand, when the amount of nor-yet-reproduced MP3 data is set at a small amount (for example, when the amount is set at 20% of the reproduction area AR 2 ), the disk analysis process can be performed rapidly.  
         [0047]    Moreover, when the disk analysis is suspended and additional data for reproduction is read, the ROM decoder  26  designates an address at which the additional data is read to the microcomputer (MCU)  24  to request a readout access of the CD  10 .  
         [0048]    As described above, according to the data reproducing device of this embodiment, the time between the recognition of the CD  10  and the reproduction thereof can be made almost equal to the time until the predetermined number of files are detected in the disk analysis process. As a result, the reproduction of the first music can be started in about a few seconds after the data reproducing device recognizes the CD  10 . This makes it possible to greatly reduce user&#39;s waiting time until the reproduction of the first music is started.  
         [0049]    Further, in the related data reproducing device, there is a large difference in the time required for disk analysis depending on the directory structure and number of files of a disk (CD  10 ), but according to this embodiment, the reproduction becomes possible at a point in time when the predetermined number of files are detected, whereby a difference in the time required until the reproduction is started, which is caused by a difference in disk structure, can be almost eliminated.  
       Second Embodiment  
       [0050]    Generally, disk analysis is performed on a directory-by-directory basis. Therefore, in the second embodiment, at a point in time when a predetermined number of directories including a file or files are detected, the disk analysis is temporarily suspended and file reproduction is started.  
         [0051]    [0051]FIG. 6 is a flowchart explaining the contents of a disk analysis process according to this embodiment. As can be seen from FIG. 6, in the disk analysis process according to this embodiment, step S 30  is executed in place of step S 12  in the aforementioned first embodiment.  
         [0052]    Namely, the controller of the ROM decoder  26  performs a disk analysis and judges whether or not a predetermined number of directories including a file or files (media file or files) are detected (step S 30 ). Then, the disk analysis is performed until the predetermined number of directories including a file or files are detected.  
         [0053]    When the predetermined number of directories including a file or files are detected (step S 30 : Yes), the disk analysis is temporarily suspended (step S 14 ), and reproduction of an analyzed file or analyzed files is started (step S 16 ).  
         [0054]    In this embodiment, the predetermined number of directories is, for example, one. Hence, the file aaa.mp3 under the &lt;root&gt; directory shown in FIG. 2 is detected, and at a point in time when information on this file is stored in the file table FTB, the disk analysis is suspended, and reproduction of the file aaa.mp3 is started.  
         [0055]    As described above, according to the data reproducing device of this embodiment, the time between the recognition of the CD  10  and the reproduction thereof can be made almost equal to the time until a predetermined number of directories including a file or files are detected in the disk analysis process. As a result, the reproduction of the first music can be started in about a few seconds after the data reproducing device recognizes the CD  10 . This makes it possible to greatly reduce user&#39;s waiting time until the reproduction of the first music is started.  
         [0056]    Further, in the related data reproducing device, there is a large difference in the time required for disk analysis depending on the directory structure and number of files of a disk (CD  10 ), but according to this embodiment, the reproduction becomes possible at a point in time when the predetermined number of directories are detected, whereby a difference in the time required until the reproduction is started, which is caused by a difference in disk structure, can be almost eliminated.  
         [0057]    Furthermore, when the disk analysis is restarted after it is temporarily suspended, as concerns the predetermined number of directories, the disk analysis thereof is completed, whereby the time required for disk analysis can be reduced further than in the first embodiment. This is because in the first embodiment, disk analysis needs to be performed again on a directory or directories from which the predetermined number of files are detected to confirm whether other files exist therein.  
         [0058]    It should be mentioned that the present invention is not limited to the aforementioned embodiments, and various changes may be made therein. For example, the data stored in the CD 10  is compressed by the MP3 in the aforementioned embodiments, but the data may be compressed in some other format such as WMA (Windows Media Audio). In addition, the data stored in the CD  10  is not necessarily compressed data.  
         [0059]    Moreover, the aforementioned embodiments are explained with a case where the data stored in the CD  10  is audio data as their example, but some other kind of data such as image data may be stored in the CD  10 . In this case, it is suitable to use a device corresponding to the kind of the data as the data reproducing device.  
         [0060]    Further, the CD  10  is used as an example of a record medium for recoding data in the aforementioned embodiments, but the present invention is applicable to other record media such as a DVD (Digital Versatile Disc).  
         [0061]    Furthermore, in the aforementioned embodiments, the reproduction of data on the detected files is started when it is judged that the predetermined number of files are detected (the first embodiment) or when it is judged that the predetermined number of directories including a file or files are detected (the second embodiment), but the reproduction of data may be started when both of these are detected. In other words, by using the first embodiment and the second embodiment in combination, when it is judged the predetermined number of files and the predetermined number of directories including a file or files are detected, the reproduction of data may be started.  
         [0062]    Additionally, the data buffer  30  is built in the semiconductor chip  50  in the aforementioned embodiments, but the entire data buffer  30  may be externally mounted. Besides, a part of the data buffer  30  may be externally mounted to the semiconductor chip  50 . For example, it is also possible to internally mount the file table area AR 3  in the semiconductor chip  50 , and externally mount the disk analysis area AR 1  and the reproduction area AR 2  to the semiconductor chip  50 .