Abstract:
An information processing apparatus is disclosed which includes: a retrieving element for retrieving storage medium information and image data information from a memory formed integrally with a storage medium having image data recorded thereon; a recording element for recording to a database the image data information in conjunction with the storage medium information, the image data information having been retrieved by the retrieving element; and a displaying element for displaying the storage medium information and the image data information recorded by the recording element.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to an information processing apparatus, an information processing method, and a program. More particularly, the invention relates to an information processing apparatus, an information processing method, and a program whereby the contents of image data recorded on a storage medium such as a cassette tape are readily verified.  
           [0002]    Image data picked up by a digital video camera are recorded on a DVC (digital video camera) cassette tape loaded in the camera. At a later date, a user may wish to verify the contents of the image data recorded on the cassette tape. In such a case, a personal computer may be used to display a list of image data retained on the cassette tape. A program for running the computer for the purpose performs a number of steps: playing back the cassette tape on fast forward so as to acquire the image data therefrom, detecting discontinuities in the acquired image data, and displaying images representative of the discontinuities so as to indicate a list of the image data held on the cassette tape.  
           [0003]    One disadvantage of the arrangement above is that the program does not guarantee the quality of the image data reproduced from the tape on fast forward. That is, some data required for detecting the discontinuities can get lost, which makes discontinuity detection inaccurate. Another disadvantage is that if the discontinuities were detected from normally reproduced image data, the detection would be performed with precision but it would take an inordinately long time because the entire range of the cassette tape needs to be played back normally.  
           [0004]    Furthermore, when thumbnail (bit map) images are obtained from the image data to represent their contents in a visually easy-to-understand manner, the quality of the thumbnails tends to be poor since they are based on the image data reproduced on fast forward. On the other hand, using the normally reproduced image data to prepare thumbnail images would require too much time.  
           [0005]    Although it is possible to enter a list of image data recorded on each cassette tape into a database or like facility, the cassette tape in question cannot be associated automatically with that image data list because cassette tapes are given no unique definition information (i.e., identifiers) in a format readable by a personal computer. To ascertain whether an image data list corresponds to a given cassette tape has so far required that the user visually check the label or other indications on the cassette tape in question. The proceedings have proved bothersome and time-consuming.  
         SUMMARY OF THE INVENTION  
         [0006]    The present invention has been made in view of the above circumstances and provides an information processing apparatus, an information processing method, and a program whereby the contents of image data recorded on a storage medium such as a cassette tape are readily ascertained.  
           [0007]    According to an aspect of the present invention, there is provided an information processing apparatus including: retrieving element for retrieving storage medium information and image data information from a memory formed integrally with a storage medium having image data recorded thereon; recording element for recording to a database the image data information in conjunction with the storage medium information, the image data information having been retrieved by the retrieving element; and displaying element for displaying the storage medium information and the image data information recorded by the recording means.  
           [0008]    According to another aspect of the present invention, there is provided an information processing method including the steps of: retrieving storage medium information and image data information from a memory formed integrally with a storage medium having image data recorded thereon; recording to a database the image data information in conjunction with the storage medium information, the image data information having been retrieved in the retrieving step; and displaying the storage medium information and the image data information recorded in the recording step.  
           [0009]    According to still another aspect of the present invention, there is provided a program for causing a computer to carry out the steps of: retrieving storage medium information and image data information from a memory formed integrally with a storage medium having image data recorded thereon; recording to a database the image data information in conjunction with the storage medium information, the image data information having been retrieved in the retrieving step; and displaying the storage medium information and the image data information recorded in the recording step.  
           [0010]    The information processing apparatus, information processing method, and program according to the invention retrieve storage medium information and image data information from a built-in memory of a storage medium containing image data, record the retrieved image data information to a database in conjunction with the storage medium information, and allow the recorded storage medium information and image data information to be displayed. The inventive scheme thus permits easy verification of the contents of image data recorded on the storage medium such as a cassette tape.  
           [0011]    The above and other objects, features and advantages of the present invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings in which like parts or elements denoted by like reference symbols. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is a block diagram showing a typical structure of a personal computer to which this invention is applied;  
         [0013]    [0013]FIGS. 2A and 2B are explanatory views of MIC information acquired by the personal computer of FIG. 1;  
         [0014]    [0014]FIG. 3 is an explanatory view depicting a typical structure of a database used by the personal computer of FIG. 1;  
         [0015]    [0015]FIG. 4 is an explanatory view indicating another structure of the database used by the personal computer of FIG. 1;  
         [0016]    [0016]FIG. 5 is a flowchart of steps performed by the personal computer of FIG. 1 in retrieving MIC information;  
         [0017]    [0017]FIG. 6 is a flowchart of steps carried out by the personal computer of FIG. 1 in acquiring thumbnail images;  
         [0018]    [0018]FIG. 7 an explanatory view of a thumbnail image acquisition list used by the personal computer of FIG. 1;  
         [0019]    [0019]FIG. 8 is an explanatory view of an MIC-ID detected in step S 39  of FIG. 6;  
         [0020]    [0020]FIG. 9 is an explanatory view illustrating another structure of the database used by the personal computer of FIG. 1; and  
         [0021]    [0021]FIG. 10 is a block diagram showing a typical hardware configuration of the personal computer. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]    [0022]FIG. 1 is a block diagram showing an internal structure of a personal computer  1  that runs an image data information acquisition program (i.e., an application) embodying the invention.  
         [0023]    The personal computer  1  works as an image data information acquisition apparatus by running the image data information acquisition program under an operating system such as Windows (registered trademark) 2000. As shown in FIG. 1, the personal computer  1  is connected via an IEEE 1394 bus (shown in FIG. 10) to a digital camcorder (camera-integrated DVTR (digital video tape recorder))  2  acting as an image pickup/playback device. The camcorder  2  is loaded with a cassette tape  3 .  
         [0024]    The cassette tape  3  incorporates an MIC (memory in cassette)  4 . Image data picked up by the camcorder  2  are recorded on the cassette tape  3 . The MIC  4  is constituted illustratively by a flash memory that accommodates information unique to the cassette tape  3  (called the cassette information hereunder) or information about the image data held on the cassette tape  3  (called the image data information hereunder). Details of such information will be discussed later with reference to FIGS. 2A and 2B.  
         [0025]    Under control of an operation control unit  11  in the personal computer  1 , the camcorder  2  retrieves the cassette information or image data information from the MIC  4  built in the cassette tape  3 , and transmits to the personal computer  1  a transport stream of image data retrieved from the cassette tape  3  and compressed by MPEG-2 (Moving Picture Experts Group Phase 2) standards.  
         [0026]    The operation control unit  11  communicates with the camcorder  2  in accordance with IEC (International Electrotechnical Commission) 61883-1. Further, the operation control unit  11  monitors the status of the camcorder  2  and controls its operation using a command set described in the AV/C Tape Recorder/Player Subunit Specification, Version 2.1. Furthermore, the operation control unit  11  acquires the cassette information or image data information retrieved by the camcorder  2  from the MIC  4  and supplies what is acquired to a database management unit  12 .  
         [0027]    Based on the cassette information or image data information from the operation control unit  11 , the database management unit  12  searches through an information database  13  for relevant information, or records the cassette information or image data information to the database  13 . Further, the database management unit  12  causes a display unit  14  to display information held in the information database  13 .  
         [0028]    A control unit  15  controls the personal computer  1  as a whole where thumbnail images are to be acquired from the image data recorded on the cassette tape  3  loaded in the camcorder  2 , as will be discussed later with reference to FIG. 6.  
         [0029]    A stream reception analysis unit  16  includes a TS (transport stream) reception unit  21 , a stream separation unit  22 , an ID detection unit  23 , a decoding unit  24 , and a temporary image storage unit  25 . The TS reception unit  21  receives from the camcorder  2  a transport stream composed of compressed MPEG-2 image data (video stream) containing an MIC-ID, and supplies what is received to the stream separation unit  22 .  
         [0030]    The stream separation unit  22  reconstitutes a video elementary stream (image stream) from the transport stream and feeds the reconstituted stream to the ID detection unit  23 . In turn, the ID detection unit  23  detects the MIC-ID (to be discussed later with reference to FIGS. 2A and 2B) from the video elementary stream and compares the detected MIC-ID with the previously detected MIC-ID in order to detect an MIC-ID discontinuity.  
         [0031]    The decoding unit  24  decodes an I-picture that appears for the first time after detection by the ID detection unit  23  of the MIC-ID discontinuity from the video elementary stream. The decoded I-picture along with the MIC-ID in effect at that point is stored as a thumbnail image into the temporary image storage unit  25  by the decoding unit  24 . Having accommodated the MIC-ID and thumbnail image, the temporary image storage unit  25  notifies the control unit  15  that the MIC-ID and thumbnail image have been acquired.  
         [0032]    Described below with reference to FIGS. 2A and 2B is the information held in the MIC  4  incorporated in the cassette tape  3 .  
         [0033]    The information stored in the MIC  4  (called the MIC information hereunder) is made up of two kinds of information: cassette information shown illustratively in FIG. 2A, and image data information depicted in FIG. 2B.  
         [0034]    The cassette information is individualized information about each cassette tape  3 . The cassette information includes a cassette serial number, the last MIC-ID, and a cassette label. The cassette serial number is unique to the cassette tape  3  of interest. The last MIC-ID is an MIC-ID (to be described later by referring to FIG. 2B) assigned to the most recently recorded image data among the image data retained on the cassette tape  3 . When new image data are recorded to the cassette tape  3 , the last MIC-ID is replaced by the MIC-ID allocated to the newly added image data. The cassette label is constituted by a character string and a display attribute displayed as the label of the cassette tape  3 . Cassette labels are entered by the user through an input unit  49  such as a keyboard (FIG. 10).  
         [0035]    The image data information concerns each of data items making up the image data recorded on the cassette tape  3 . The image data information includes a recording start point, a recording end point, an MIC-ID, and a recording date and time. The recording start point refers to that location on the cassette tape  3  from which the image data item in question starts being recorded; the recording end point signifies that location on the cassette tape  3  at which recording of the image data item of interest has ended. The MIC-ID is a unique number assigned to the image data item. The recording date and time are self-explanatory; they indicate the date and time at which the image data item in question was recorded.  
         [0036]    Retrieving the MIC information allows the personal computer  1  to acquire the cassette information unique to the cassette tape  3  and the image data information about the image data recorded on the cassette tape  3 . The acquired image data information is written to the information database  13  in conjunction with the cassette information.  
         [0037]    How the image data information is managed in the information database  13  will now be described by referring to FIGS. 3 and 4.  
         [0038]    The information database  13  holds at least a cassette master table shown in FIG. 3 and a recording table depicted in FIG. 4. The cassette master table has the last MIC-ID&#39;s and cassette labels arranged in conjunction with cassette serial numbers. The cassette master table in FIG. 3 is shown managing the cassette information (see FIG. 2A) as part of the MIC information. Illustratively, an information item “a” in the table indicates that the cassette tape having a cassette serial number “0x3567a4ee01” has the last (i.e., the most recently assigned) MIC-ID “0x4800” pointing to a cassette tape labeled “Kindergarten Graduation Ceremony.” 
         [0039]    Meanwhile, the image data information (FIG. 2B) as another part of the MIC information is managed using the so-called recording table as shown in FIG. 4. In the recording table, the image data information is arranged in conjunction with cassette serial numbers. Illustratively, an image data information item “c” in the recording table indicates that an image data item recorded on the cassette tape having the cassette serial number “0x3567a4ee01” is assigned an MIC-ID “0x0001”; that recording of the image data item in question starts at a location “0x37a219” and ends at a location “0x37ff82” on the cassette tape; that the image data item was recorded on Mar. 10, 2001 (recording start date) starting at 9:00:02 (recording start time); and that the image data item includes a star-shaped thumbnail image. By contrast, an image data information item “d” is shown having no thumbnail image.  
         [0040]    Given the user&#39;s instructions, the database management unit  12  outputs the cassette master table and recording table from the information database  13  to the display unit  14 . In turn, the display unit  14  displays the cassette master table and recording table having been received.  
         [0041]    Described below with reference to the flowchart of FIG. 5 is how an MIC information retrieval process is carried out by the image data information acquisition program running on the personal computer  1 . The process is executed every time immediately after the personal computer  1  is booted up.  
         [0042]    When the image data information acquisition program is initiated, the operation control unit  11  establishes connection with the camcorder  2  in step S 1  and issues a MEDIUM INFO command to the camcorder  2 . In response to the command, the camcorder  2  notifies the operation control unit  11  whether or not a cassette tape is loaded inside.  
         [0043]    Given the notice from the camcorder  2 , the operation control unit  11  judges whether or not the camcorder  2  is loaded with the cassette tape  3  from which to retrieve image data information in step S 2 . If the cassette tape  3  is found loaded in the camcorder  2 , step S 3  is reached.  
         [0044]    In step S 3 , the operation control unit  11  issues an OPEN MIC command and a READ MIC command to the camcorder  2 . In response to the commands, the camcorder  2  retrieves cassette information (FIG. 2A) as part of the MIC information read from the MIC  2  in the cassette tape  3 , and transmits the retrieved cassette information to the operation control unit  11 . The operation control unit  11  forwards the received cassette information to the database management unit  12 .  
         [0045]    In step S 4 , the database management unit  12  judges whether or not the cassette serial number in the cassette information is already recorded in the information database  13 . If the cassette serial number is judged already recorded in the information database  13 , then step S 5  is reached.  
         [0046]    In step S 5 , the database management unit  12  compares the last MIC-ID corresponding to the cassette serial number in the cassette information read in step S 3 , with the last MIC-ID in the cassette master table (FIG. 3) retained in the information database  13 . In step S 6 , the database management unit  12  checks to see whether or not the two last MIC-ID&#39;s are different.  
         [0047]    If in step S 6  the last MIC-ID retrieved from the MIC  4  is judged different from the last MIC-ID in the cassette master table already recorded in the information database  13 , that means new image data have been added to the cassette tape  3 . If that is the case, the database management unit  12  requests the operation control unit  11  to retrieve image data information from the MIC  4 .  
         [0048]    The request sent by the database management unit  12  to read the image data information from the MIC  4  causes the operation control unit  11  to retrieve the image data information (FIG. 2B) as another part of the MIC information from the MIC  4  in the cassette tape  3  in step S 7 . The retrieved image data information is supplied to the database management unit  12 .  
         [0049]    In step S 8 , the database management unit  12  compares the supplied image data information from the operation control unit  11  with the image data information in the recording table of the information database  13  in terms of their MIC-ID&#39;s, and updates only the different image data information. During this MIC information retrieval process, the thumbnail images in the recording table are not updated.  
         [0050]    If in step S 4  the cassette serial number is not judged recorded yet in the information database  13 , the MIC information retrieval process is regarded as carried out for the first time on the cassette tape  3  in question. In that case, step S 9  is reached in which the database management unit  12  records anew the cassette information to the information database  13 .  
         [0051]    In step S 10 , the database management unit  12  requests the operation control unit  11  to retrieve the image data information from the MIC  4 . Given the request, the operation control unit  11  retrieves the image data information as part of the MIC information from the MIC  4  in the cassette tape  3  in step S 10 . The retrieved image data information is fed to the database management unit  12 . In step S 11 , the database management unit  12  records to the information database  13  the image data information supplied from the operation control unit  11 .  
         [0052]    Step S 12  is reached following step S 8  or step S 11 . In step S 12 , the database management unit  12  causes the display unit  14  to display the updated cassette master table and recording table.  
         [0053]    If in step S 2  the cassette tape  3  from which to retrieve image data information is not judged loaded in the camcorder  2 , then the operation control unit  11  disconnects connection with the camcorder  2  and terminates the process. At this point, the display unit  14  may be arranged to display an error message.  
         [0054]    If in step S 6  the last MIC-ID retrieved from the MIC  4  is judged to be the same as the last MIC-ID held in the cassette master table in the information database  13 , then the database management unit  12  recognizes that no new image data have been recorded to the cassette tape  3  and that there is no need to update any information in the information database  13 . In that case, the database management unit  12  notifies the operation control unit  11  of termination of the process. In turn, the operation control unit  11  disconnects connection with the camcorder  2  and brings the process to an end.  
         [0055]    The steps described above allow the user easily to verify and update the contents of the image data recorded on each cassette tape  3 , whereby image data management is accomplished more easily than before. Because no processing is performed on the already-retained cassette information and image data information, the time required for information registration is appreciably shortened.  
         [0056]    A thumbnail image acquisition process is described below with reference to the flowchart of FIG. 6. This process is carried out on the assumption that the MIC information retrieval process, discussed above by referring to FIG. 5, has already been executed. When the user gives necessary instructions through the input unit  49  such as a keyboard (to be discussed later with reference to FIG. 10), the control unit  15  takes over a major portion of control over the process.  
         [0057]    In step S 31 , the control unit  15  causes the operation control unit  11  to acquire the cassette serial number of the cassette tape  3  from the camcorder  2 .  
         [0058]    In step S 32 , the control unit  15  causes the database management unit  12  to acquire, from the recording table (FIG. 4) in the information database  13 , all image data information corresponding to the cassette serial number obtained in step S 31 .  
         [0059]    In step S 33 , the control unit  15  selects only the image data information without thumbnail (bit map) images from all image data information acquired in step S 32 , and prepares a list such as one shown in FIG. 7. The control unit  15  then rearranges the list entries in the ascending order of their recording start points (the list is called the thumbnail image acquisition list hereunder).  
         [0060]    In the thumbnail image acquisition list of FIG. 7, image data information items “d” and “f” are seen associated with the same cassette serial number “0x3567a4ee01” (of the cassette tape  3 ). The recording start points of the image data information items “d” and “f” are “0x3800e2” and “0x39b165” respectively, indicating that the items of image data information are arranged in the ascending order of their recording start points. It is also shown that the image data information items “d” and “f” have no recorded thumbnail images yet. In FIG. 7, the items or entries whose counterparts are shown in FIG. 4 discussed above are given like reference numerals, and their descriptions are omitted where redundant.  
         [0061]    In step S 34 , the control unit  15  causes the operation control unit  11  to issue a REWIND command to the camcorder  2 . Given the command, the camcorder  2  rewinds the cassette tape  3  loaded inside.  
         [0062]    In step S 35 , the control unit  15  causes the stream reception analysis unit  16  to start operating. In step S 36 , the operation control unit  11  under control of the control unit  15  causes the camcorder  2  to play back the cassette tape  3  on fast forward. The stream reception analysis unit  16 , once started, operates continuously until it is instructed to terminate its processing.  
         [0063]    With the cassette tape  3  being played back on fast forward in step S 36 , the camcorder  2  transmits to the personal computer  1  a transport stream of compressed MPEG-2 image data (video stream). In step S 37 , the TS reception unit  21  receives the transport stream from the personal computer  1  and forwards the received stream to the stream separation unit  22 .  
         [0064]    In step S 38 , the stream separation unit  22  reconstitutes a video elementary stream out of the input transport stream. The video elementary stream is supplied to the ID detection unit  23 .  
         [0065]    In step S 39 , the ID detection unit  23  detects an MIC-ID from the input video elementary stream. This MICID is written in the format shown in FIG. 8 at a location of “extension and user data (2)” stipulated in the ISO/IEC 13818-2: 1995 6 Video Bit-stream Syntax and Semantics 6.2.  
         [0066]    [0066]FIG. 8 illustrates a syntax of “user_data( )” recorded in conjunction with an MPEG-2 image data item. In FIG. 8, the second line “user_data_start_code” points to that location on the cassette tape  3  at which this image data item starts being recorded. The third line “neo_id” is an ID representing the camcorder  2  that has recorded the image data item in question. The fourth line “search_data 13  id” shows that if the value is “0x01,” then the image data item is subject to search. The fifth line “mic_id_LSB (least significant bit)” indicates low-order eight bits of the MIC-ID for the image data item in question. The sixth line “mic_id_MSB (most significant bit)” indicates high-order eight bits of the MIC-ID for the image data item. The seventh line “marker_bit” is used to prevent confusion with a start code of MPEG data. The eighth line “frame_count” represents a serial number allocated to an image data item in an image data sequence reproduced from the tape on fast forward. The ID detection unit  23  detects “mic_id_LSB” and “mic_id_MSB” as the MIC-ID.  
         [0067]    In step S 40 , the ID detection unit  23  checks to see if the detected MIC-ID differs from the previously detected MIC-ID. If the two MIC-ID&#39;s are judged different, then step S 41  is reached. If there is no previously detected MIC-ID (i.e., if the MIC-ID is detected for the first time), the subsequent processing is the same as when the two MIC-ID&#39;s are found to differ from each other.  
         [0068]    If in step S 40  the detected MIC-ID is judged identical to the previously detected MIC-ID, then step S 37  is reached again and the subsequent steps are repeated.  
         [0069]    MIC-ID&#39;s have different values for different cuts of image data and thus represent a discontinuity in case of a mismatch therebetween. A detected MIC-ID discontinuity permits detection of a boundary between different cuts of image data.  
         [0070]    If the detected MIC-ID is judged different from the previously detected MIC-ID, step S 41  is reached as described above. In step S 41 , the ID detection unit  23  extracts from the video elementary stream an I-picture that appears for the first time after the detected MIC-ID has been found different from the previously detected MIC-ID, and supplies what is extracted to the decoding unit  24 . The decoding unit  24  decodes the received I-picture and reduces in size the decoded picture into a thumbnail image. The thumbnail image along with the detected MIC-ID is sent to the temporary image storage unit  25  for storage.  
         [0071]    In step S 42 , the ID detection unit  23  notifies the control unit  15  that the MIC-ID and the thumbnail image of the image data identified by that MIC-ID have been acquired. In step S 43 , the control unit  15  judges whether or not the reported MIC-ID exists in the thumbnail image acquisition list prepared in step S 33 . If the MIC-ID in question is judged to exist already in the list, then step S 44  is reached. In step S 44 , the control unit  15  acquires the thumbnail image corresponding to the MIC-ID from the temporary image storage unit  25 , and causes the database management unit  12  to record the acquired image to the information database  13  in conjunction with the MIC-ID in question.  
         [0072]    If in step S 43  the reported MIC-ID is judged absent in the thumbnail image acquisition list, then step S 44  is skipped (the thumbnail image need not be retained because there already exists the thumbnail image in the information database).  
         [0073]    In step S 45 , the control unit  15  erases the thumbnail image held in the temporary image storage unit  25 .  
         [0074]    In step S 46 , the control unit  15  judges whether or not the reported MIC-ID is the same as the MIC-ID of the last image data in the thumbnail image acquisition list. If the two MIC-ID&#39;s are judged different, that means there still exists a thumbnail image of image data to be acquired. In that case, step S 37  is reached again and the subsequent steps are repeated. If in step S 46  it is judged that the reported MIC-ID is the same as the MIC-ID of the last image data in the thumbnail image acquisition list (in which image data items are arranged in the ascending order of their recording start points), then step S 47  is reached. In step S 47 , the control unit  15  causes the stream reception analysis unit  16  to stop operating. Also under control of the control unit  15 , the operation control unit  11  cause the camcorder  2  to stop playing back the cassette tape  3 .  
         [0075]    In step S 48 , the database management unit  12  under control of the control unit  15  causes the display unit  14  to display the updated recording table as shown in FIG. 9. Whereas the recording table of FIG. 4 above was shown having no thumbnail image recorded for the image data information item “d,” a square-shaped thumbnail image is seen recorded for the corresponding item in the recording table of FIG. 9. The user can verify the newly recorded thumbnail image by viewing what is displayed on the display unit  14 .  
         [0076]    As described, the newly recorded image data alone are subjected to the thumbnail image acquisition process whereby an additional thumbnail image is retained in conjunction with the added image data. As opposed to conventional setups that create thumbnail images of all image data, the inventive scheme processes only what is necessary and thereby shortens appreciably the time required for thumbnail image preparation.  
         [0077]    Furthermore, utilization of the I-picture extracted from the image data reproduced from the tape on fast forward helps improve the quality of thumbnail images.  
         [0078]    [0078]FIG. 10 is a block diagram showing a typical hardware configuration of the personal computer described as performing the series of steps above.  
         [0079]    In FIG. 10, a CPU (central processing unit)  41  carries out diverse processes based on the programs held in a system memory  42  or on the programs loaded from a hard disc drive  51  into the system memory  42 . The system memory  42  also accommodates data needed for the CPU  41  to execute its processes. The system memory  42  is controlled by a memory controller  43 . A graphics controller  44  controls a display  45  constituted by a CRT (cathode ray tube) or an LCD (liquid crystal display) for image display.  
         [0080]    The CPU  41 , memory controller  43 , and graphics controller  44  are interconnected via a system bus  46 . A PCI bus controller  47  is also connected to the system bus  46 .  
         [0081]    The PCI bus controller  47  is connected to a PCI bus  48 . The PCI bus  48  is further connected with a USB controller  50  for controlling the input unit  49  including a keyboard and a mouse, with a hard disc controller  52  for controlling the hard disc drive  51 , and with an IEEE 1394 bus controller  53 . The IEEE 1394 bus controller  53  is connected via an IEEE 1394 bus  54  to the camcorder  2 . Given suitable instructions, the IEEE 1394 bus controller  53  exchanges control commands and MPEG-2 transport streams with the camcorder  2  over the IEEE 1394 bus  54 .  
         [0082]    In this specification, the steps which are stored on a storage medium and which describe the programs to be executed represent not only the processes that are carried out in the depicted sequence (i.e., on a time series basis) but also processes that are conducted parallelly or individually.  
         [0083]    As many apparently different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments thereof except as defined in the appended claims.