Patent Publication Number: US-2005117464-A1

Title: Disk playback apparatus and method

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a disk playback apparatus and method for playing back a plurality of pieces of content, which are recorded on one disk and for which the playback method is different.  
      2. Description of the Related Art  
      Previously, a playback system to which a plurality of playback apparatuses such as CD players and DVD players are connected has been known (for example, refer to Japanese Unexamined Patent Application Publication No. 2003-91924 (pages 3 to 8, FIGS. 1 to 7)). In this playback system, devices of different categories (for example, CD players and DVD players) can be connected and each of the pieces of the recorded content can be played back. Furthermore, when devices of the same category (for example, a plurality of CD players) are connected, these devices can be assigned to an input selection item of the same name. As a result, the ease of operation when the number of connected devices of the same category is increased can be improved.  
      In recent years, new rewritable disk media such as CD-Rs and DVD-Rs have become popular, so that recording can be performed in accordance with an operation from a user in such a manner that different types of information, for example, information for CD-DA (audio CD) and information for MP3, coexist in one disk medium. However, in the playback system disclosed in Japanese Unexamined Patent Application Publication No. 2003-91924 above, considerations are made to such an extent that a plurality of devices of the same or different categories are connected, but considerations to such an extent that one apparatus plays back a disk medium on which a plurality of pieces of information are recorded, for which the playback method is different, are not made. Therefore, the ease of operation when the recorded content of such a disk medium is played back cannot be improved. For example, some of recent CD players are capable of playing back the recorded content of both a disk for CD-DA and a disk for MP3 by selectively interchanging the disks. However, when one disk is loaded, the playback method in accordance with the recorded content thereof is determined; therefore, when the information is recorded in such a manner that information for CD-DA and information for MP3 coexist in one disk, only the information of one of them is played back. Furthermore, when a disk changer capable of loading a plurality of disks at the same time is used, the playback method is determined in units of disks. For example, when a disk for CD-DA is loaded into slot  1  and a disk for DVD-video is loaded into slot  2 , the user specifies the slot number and the playback method so as to play back a desired disk (there are cases in which, when the slot number is specified, the playback method for the disk loaded into that slot is automatically set). Therefore, if information for which the playback method is different is recorded on one disk, the information whose playback method differs from the playback method determined in such a manner as to correspond to one slot does not become a playback target even if that information is recorded on the disk loaded into this slot, and a case in which playback cannot be performed might occur.  
     SUMMARY OF THE INVENTION  
      The present invention has been made in view of the above. An object of the present invention is to provide a disk playback apparatus and method capable of improving the ease of operation when a plurality of pieces of content, which are recorded on one disk and for which the playback method is different, are played back.  
      To achieve the above-mentioned object, in one aspect, the present invention provides a disk playback apparatus including: a recording information analysis section for analyzing the type of recording information recorded on a disk-shaped recording medium to be played back; a management information creation section for creating management information such that each of a plurality of pieces of the recording information corresponds to mutually different identification information on the basis of the analysis result by the recording information analysis section when a plurality of different types of the recording information are recorded on the disk-shaped recording medium; and a playback section for performing a playback operation on the basis of the recording information corresponding to the identification information.  
      In another aspect, the present invention provides a disk playback method including: a first step of analyzing a type of recording information recorded on a disk-shaped recording medium to be played back; a second step of creating management information such that each of a plurality of pieces of the recording information corresponds to mutually different identification information on the basis of the analysis result in the first step when a plurality of different types of the recording information are recorded on the disk-shaped recording medium; and a third step of performing a playback operation on the basis of the recording information corresponding to the identification information  
      Even when a plurality of types of recording information are recorded on a disk-shaped recording medium, by specifying identification information corresponding to each piece of recording information, each piece of recording information can be played back. Thus, it is possible to improve the ease of operation when the recording information is played back using a disk-shaped recording medium on which a plurality of types of recording information are recorded in a mixed manner.  
      The disk playback apparatus may further include a first display section for displaying the content of the management information created by the management information creation section. The disk playback method may further include a fourth step of displaying the content of the management information created in the second step. As a result, it becomes possible for a user to confirm the identification information corresponding to the recording information of each disk-shaped recording medium, and the ease of operation can be improved further.  
      Preferably, the management information includes the identification information and specific information of the type of the recording information corresponding to the identification information. As a result, it becomes possible for the user to specify each piece of identification information and the type of the recording information corresponding to each piece of the identification information, and thus, the ease of operation can be improved further.  
      The disk playback apparatus may further include a disk housing section in which a plurality of the disk-shaped recording media can be housed and from which one of the disk-shaped recording media, which is to be played back by the playback section, is selectively taken out. The management information creation section preferably creates the management information corresponding to a plurality of the disk-shaped recording media that are actually housed in the disk housing section. Alternatively, in the second step, preferably, the management information corresponding to a plurality of the disk-shaped recording media that are actually housed in the disk housing section is created. As a result, a playback with identification information being specified for one or a plurality of pieces of recorded content recorded on each of a plurality of disk-shaped recording media can be performed. Thus, the ease of operation when recording information is played back using one or more disk-shaped recording media on which a plurality of types of recording information are recorded in a mixed manner can be improved.  
      Preferably, different identification information is used with respect to the combination of the housing position of the disk housing section and the type of one or a plurality of pieces of recording information of the disk-shaped recording medium housed at each housing position. As a result, even when a plurality of pieces of recording information are contained in each of a plurality of disk-shaped recording media, it becomes possible to specify each piece of recording information using the identification information, and the ease of operation when the recording information is specified can be improved.  
      Preferably, the identification information is a virtual slot number having a different serial number. As a result, it becomes possible to manage the recording information recorded on each disk-shaped recording medium by using a virtual slot number similar to the slot number indicating the housing position of the disk housing section such as a disk changer. Thus, it is possible to realize satisfactory ease of operation that is compatible with a conventional apparatus provided with a disk changer.  
      Preferably, examples of the disk-shaped recording medium include a CD and a DVD, and the playback section performs a playback operation on both the CD and the DVD. Alternatively, in the third step, preferably, a playback operation is performed on both the CD and the DVD. In this manner, when it is possible to play back both the CD and the DVD, the number of types of recording information increases, and the complexity when a playback is instructed increases further. Therefore, by performing a playback. with identification information being given for each type of the recording information, the ease of operation can be improved further.  
      Preferably, the identification information is provided so as to correspond to each of the pieces of recording information for which the playback method is different. As a result, even when a plurality of types of information for which the playback method is different, for example, data for CD-DA and a MP3 file, are recorded in a mixed manner on one disk-shaped recording medium, by specifying each piece of identification information, the recording information of each playback method can be specified. Thus, it becomes possible to specify each recording information with a lesser amount of operation, and a playback operation can be performed with efficiency.  
      The disk playback apparatus may further include: an operation section for specifying a type of the recording information; and an identification information extraction section for extracting, from the disk-shaped recording medium, the identification information corresponding to the recording information of the type specified using the operation section. Preferably, the playback section performs a playback operation on the basis of the identification information extracted by the identification information extraction section. As a result, since the playback of the recording information can be performed by the user himself/herself by specifying the type, only the recording information of the specified type can be played back.  
      Preferably, the recording information is classified, in accordance with a playback operation, into first recording information in which a display signal is contained and second recording information in which a display signal is not contained. An identification information extraction section for extracting the identification information corresponding to the second recording information from the disk-shaped recording medium when the second display section for performing a display based on the display signal is being used in applications other than this display operation may further be provided. Preferably, the playback section performs a playback operation on the basis of the identification information extracted by the identification information extraction section. As a result, when the display section is being used in another application, for example, a map display for a navigation apparatus, recording information, such as a music source, that does not involve a display can be made a target to be played back in such a manner as to be narrowed in advance. Thus, the ease of operation when the playback operation is instructed can be improved.  
      Preferably, the operation section is used to select one of the plurality of pieces of identification information extracted by the identification information extraction section, and the playback section performs a playback operation on the basis of one of the pieces of the identification information, which is selected by an operation using the operation section. As a result, it is possible for the user to narrow the recording information by specifying the type, and thereafter to select one piece of recording information that is desired to be played back from among the recording information. Therefore, the ease of operation when one piece of recording information is selectively played back can be improved even more.  
      Preferably, the playback section sequentially plays back the recording information that is randomly selected on the basis of the identification information extracted by the identification information extraction section. As a result, it is possible to perform a random playback without specifying the recording information of the same type as a target to be played back each time. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  shows the overall configuration of a disk playback apparatus according to an embodiment of the present invention;  
       FIG. 2  shows an operation procedure for identifying the medium type of a disk and the recorded content thereof;  
       FIG. 3  shows a specific example of the content of a disk loaded into each slot of a disk changer;  
       FIG. 4  shows a specific example of management information;  
       FIG. 5  is a flowchart showing an operation procedure for analyzing the content of a disk as a CD medium;  
       FIG. 6  is a flowchart showing an operation procedure for analyzing the content of a disk as a DVD medium;  
       FIG. 7  is a flowchart showing an operation procedure when a source is switched for each playback method;  
       FIG. 8  is a flowchart showing a playback operation in a case where the usage of a display device is taken into consideration; and  
       FIG. 9  is a flowchart showing an operation procedure for specifying a source and for randomly playing back the recorded content of one or more pseudo-slots corresponding to the specified source.  
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      A disk playback apparatus of an embodiment of the present invention will now be described below in detail with reference to the drawings.  
       FIG. 1  shows the overall configuration of a disk playback apparatus according to the embodiment of the present invention. A disk playback apparatus  1  of this embodiment shown in  FIG. 1  plays back recording information in accordance with a signal read from a disk  10 . The disk playback apparatus  1  includes a spindle motor  12 , a sled motor  14 , an optical pickup  16 , an RF amplifier  18 , a servo LSI  20 , a servo driver  22 , a disk changer  24 , a disk loading detection section  26 ,-a digital signal processing section  28 , a system controller  30 , an operation section  32 , a digital-to-analog converter (D/A)  34 , a video mixing section  36 , and a video encoder  38 .  
      The spindle motor  12  rotates a disk  10  set at a predetermined position at a predetermined speed. The sled motor  14  causes the optical pickup  16  to move in the radial direction of the disk  10 . The optical pickup  16  reads a signal recorded on the disk, and includes a semiconductor laser, a photodiode, and a focus lens. The optical pickup  16  includes a focus actuator for causing the focus lens to move nearly at a vertical direction with respect to the recording surface of the disk  10 , and a tracking actuator for causing the focus lens to move in the radial direction of the disk  10 .  
      The RF amplifier  18  generates an RF signal by amplifying a signal sent from the optical pickup  16  and by performing an equalizer process thereon, and sends the RF signal to the digital signal processing section  28 . Furthermore, the RF amplifier  18  generates a focus error (FE) signal required for focus servo and a tracking error (TE) signal required for tracking servo, and sends the signals to the servo LSI  20 .  
      The servo LSI  20  performs various servo control. More specifically, the servo LSI  20  performs phase compensation and amplification on the focus error signal sent from the RF amplifier  18 , and generates a focus actuator control signal required to control the driving state of the focus actuator within the optical pickup  16 . Furthermore, based on the control signal sent from the RF amplifier  18 , the servo LSI  20  generates a spindle motor control signal required to control the driving state of the spindle motor  12 . These signals generated by the servo LSI  20  are sent to the servo driver  22 .  
      Based on the focus actuator control signal sent from the servo LSI  20 , the servo driver  22  generates a driving voltage for the tracking actuator of the optical pickup  16 . The servo driver  22  generates a driving voltage for the sled motor  14  on the basis of the sled motor control signal sent from the servo LSI  20 . Furthermore, the servo driver  22  generates a driving voltage for the spindle motor  12  on the basis of the spindle motor control signal sent from the servo LSI  20 .  
      The disk changer  24  has a plurality of slots (for example, six slots) to which a plurality of disks  10  of CD media or DVD media can be loaded. The disk changer  24  performs an operation for moving the disk  10  loaded into one of the slots and setting it at a predetermined position at which a recording signal can be read, and for moving the disk  10  set at the predetermined position and housing it in the slot again. The disk loading detection section  26  detects the presence or absence of the disk  10  loaded into each slot of the disk changer  24 .  
      The digital signal processing section  28  performs synchronization detection and demodulation processes on the RF signal sent from the RF amplifier  18 . Thereafter, the digital signal processing section  28  performs a predetermined decoding process in accordance with the content recorded on the disk  10 , and plays back and reproduces the recorded audio or video data. In this embodiment, it is assumed that, as the disk  10 , a CD medium or a DVD medium is used, and as the recorded content (the recording information), one of (1) data for CD-DA, (2) data for video-CD, (3) data for DVD-audio, (4) data for DVD-video, (5) an MP3 file, and (6) a WMA file is recorded. Furthermore, there are cases in which a plurality of pieces of content (for example, data for CD-DA and an MP3 file) are recorded in a mixed manner on one disk  10 .  
      In order to perform a decoding process corresponding to these various pieces of recorded content, the digital signal processing section  28  includes a CD-DA playback section  100 , a video-CD playback section  102 , a compressed file playback section  104 , a DVD-video playback section  106 , and a DVD-audio playback section  108 . When the content recorded on the disk  10  is identified as data for CD-DA, the CD-DA playback section  100  plays back this content and reproduces audio data. When the content recorded on the disk  10  is identified as data for video-CD, the video-CD playback section  102  plays back this content and reproduces audio data and video data. When the content recorded on the disk  10  is identified as an MP3 file or a WMA file, the compressed file playback section  104  plays back this content and reproduces audio data. When the content recorded on the disk  10  is identified as data for DVD-video, the DVD-video playback section  106  plays back this content and reproduces audio data and video data. When the content recorded on the disk  10  is identified as data for DVD-audio, the DVD-audio playback section  108  plays back this content and reproduces audio data.  
      The system controller  30  controls the playback operation of the disk playback apparatus  1  by sending various servo instructions to the servo LSI  20  and by instructing the disk changer  24  to move the disk  10  loaded into each slot and house it. Furthermore, the system controller  30  identifies the medium type and the recorded content of the disk  10  loaded into each slot of the disk changer  24 , and instructs the digital signal processing section  28  to perform a playback operation in accordance with this identified result.  
      The operation section  32  is used for a user to perform various operations. The operation section  32  includes a cursor key and a determination key required to instruct, for example, a playback operation and a random playback operation in which a medium type or a pseudo-slot (to be described later) are specified.  
      The digital-to-analog converter  34  converts audio data sent from the digital signal processing section  28  into an analog audio signal of a predetermined channel (for example, a 5.1 channel). This analog audio signal for each channel is amplified by an amplifier (not shown), and thereafter, the analog audio signal is reproduced from a speaker  40 .  
      The video mixing section  36  mixes video data of an operation screen, etc., and text data of movie subtitles, etc., which are sent from the system controller  30 , to the video data sent from the digital signal processing section  28 . The video encoder  38  converts video data sent from the video mixing section  36  into a video signal in a predetermined format (for example, an NTSC format). This video signal is sent to the display section  42 , whereby a video image is displayed on the screen thereof.  
      The above-described system controller  30  corresponds to the recording information analysis section, the management information creation section, and the identification information extraction section. The digital signal processing section  28  and the system controller  30  correspond to the playback section. The video encoder  38  and the display section  42  correspond to the first and second display sections. The disk changer  24  corresponds to the disk housing section. The operation section  32  corresponds to the operation section.  
      The disk playback apparatus  1  of this embodiment has such a configuration. Next, a description will be given below of an operation for identifying the medium type and the recorded content of each disk  10  loaded into the disk changer  24  and a playback operation performed on the basis of this identified result.  
       FIG. 2  shows the operation procedure for identifying the medium type and the recorded content of the disk  10 . When the power is switched on or the disk changer  24  is set to a predetermined value, the system controller  30  detects the disk  10  loaded into each slot of the disk changer  24  on the basis of the detection result by the disk loading detection section  26  (step S 100 ).  
      Next, the system controller  30  selects one slot to which the disk  10  is loaded (step S 101 ), and identifies the medium type of the disk  10  loaded into this slot (step S 102 ). This identification is performed in a state in which the disk  10  is actually taken out from the slot and is set at the position where playback is possible. For a method of identifying which one of a CD medium or a DVD medium the disk  10  is, various methods have previously been used. For example, a focus error signal which is detected when the optical pickup  16  is moved perpendicularly to the recording surface of the disk  10  can be observed to identify as to which one of a CD medium or a DVD medium the disk  10  is on the basis of the number of S-shaped curves which appear and the signal level.  
      Next, the system controller  30  determines whether or not the disk  10  of interest, which is loaded into one slot, is a CD medium, on the basis of the identification result of the disk medium (step S 103 ). In the case of a CD medium, an affirmative determination is made. Next, the system controller  30  analyzes the recorded content of this disk  10  (step S 104 ). As described above, when the disk  10  is a CD medium, the recorded content is basically one of data for CD-DA, data for video-CD, an MP3 file, and a WMA file, or a combination thereof, and an analysis as to which one of them the recorded content corresponds to is performed.  
      When the disk  10  is not a CD medium, a negative determination is made in the determination of step S 103 . Next, the system controller  30  determines whether or not the disk  10  is a DVD medium (step S 105 ). When the disk  10  is a DVD medium, an affirmative determination is made. Next, the system controller  30  analyzes the recorded content of this disk  10  (step S 106 ). As described above, when the disk  10  is a DVD medium, the recorded content is basically one of data for DVD-audio, data for DVD-video, an MP3 file, and a WMA file, or a combination thereof, and an analysis as to which one of them the recorded content corresponds to is performed.  
      When the disk  10  is not a DVD medium, a negative determination is made in the determination of step S 105 . This is a case in which the disk  10  is neither a CD medium nor a DVD medium, and the system controller  30  performs predetermined error handling (step S 107 ).  
      After the error handling (step S 107 ) or after the analysis of the content of the disk  10  in steps S 104  and S 106 , the system controller  30  determines whether or not there is another slot into which the disk  10  for which analysis is not completed is loaded (step S 108 ). When there is such a slot, an affirmative determination is made. Next, the system controller  30  selects another slot into which the disk  10  for which analysis is not completed is loaded (step S 109 ). The process thereafter returns to step S 102  above, and the operation for identifying the medium type of the disk  10  loaded into this slot and subsequent steps are performed again.  
      When there are no other slots into which the disk  10  for which analysis is not yet completed is loaded, a negative determination is made in step S 108 . Next, the system controller  30  creates management information for each slot of the disk changer  24  and for each of the pieces of recorded content of the disk  10  loaded into each slot (step S 110 ), and thereafter, displays the content on the display section  42  via the video mixing section  36  and the video encoder  38  (step S 111 ).  
       FIG. 3  shows a specific example of the content of the disk  10  loaded into each slot of the disk changer  24 . As shown in  FIG. 3 , the medium type and the recorded content of the disk  10  loaded into each slot are as follows. The actual slots provided in the disk changer  24  are hereinafter referred to as “actual slots”, and virtual slots (to be described later) introduced in this embodiment are hereinafter referred to as “pseudo-slots” so that the slots are distinguished. The number of each pseudo-slot corresponds to the identification information set for each type of the recorded content. 
          Actual slot  1 : the disk  10  of a DVD medium is loaded, and the recorded content is data for DVD-video.     Actual slot  2 : the disk  10  of a CD medium is loaded, and the recorded content is provided in such a manner that data for CD-DA and an MP3 file coexist.     Actual slot  3 : the disk  10  of a DVD medium is loaded, and the recorded content is an MP3 file.     Actual slot  4 : the disk  10  of a CD medium is loaded, and the recorded content is provided in such a manner that data for DVD-audio and data for DVD-video coexist.     Actual slot  5 : the disk  10  of a CD medium is loaded, and the recorded content is video-CD.     Actual slot  6 : the disk  10  of a CD medium is loaded, and the recorded content is CD-DA.        
      In the six actual slots of the disk changer  24 , six disks  10  of such medium type and recorded content are loaded. In the management information created in step S 110  of  FIG. 2 , pseudo-slots which are set in accordance with the following rules are assumed as units. 
          (Rule 1) A different pseudo-slot is assigned to a different actual slot.     (Rule 2) A pseudo-slot is assigned to only the actual slot to which the disk  10  is actually loaded.     (Rule 3) When a plurality of pieces of data for which the playback method is different are recorded on the same actual slot, different pseudo-slots are assigned so as to correspond to the respective pieces of data.        

       FIG. 4  shows a specific example of management information created in accordance with the above rules. As shown in  FIG. 4 , the content of each pseudo-slot is as follows. 
          Virtual slot  1 : since only one type of data (data for DVD-video) is recorded on the disk  10  loaded into the actual slot  1 , the content of the actual slot  1  is assigned to the pseudo-slot  1 .     Virtual slot  2 : since two types of data (data for CD-DA and an MP3 file) are recorded on the disk  10  loaded into the next actual slot, one of them (data for CD-DA) is assigned to the pseudo-slot  2 .     Virtual slot  3 : in the pseudo-slot  3 , the other data (the MP3 file) recorded on the disk  10  loaded into the actual slot  2  is assigned.     Virtual slot  4 : since only one type of data (the MP3 file) is recorded on the disk  10  loaded into the next actual slot  3 , the content of the actual slot  3  is assigned to the pseudo-slot  4 .     Virtual slot  5 : since two types of data (data for DVD-audio and data for DVD-video) are recorded on the disk  10  loaded into the next actual slot  4 , one of them (data for DVD-audio) is assigned to the pseudo-slot  5 .     Virtual slot  6 : in the pseudo-slot  6 , the other data (the data for DVD-video) recorded on the disk  10  loaded into the actual slot  4  is assigned.     Virtual slot  7 : since only one type of data (the data for video-CD) is recorded on the disk  10  loaded into the next actual slot  5 , the content of the actual slot  5  is assigned to the pseudo-slot  7 .     Virtual slot  8 : since only one type of data (the data for CD-DA) is recorded on the disk  10  loaded into the next actual slot  6 , the content of the actual slot  6  is assigned to the pseudo-slot  8 .        
      As described above, in the example shown in  FIG. 3 , since six disks  10  are loaded into six actual slots of the disk changer  24 , and two types of data are recorded on the disks  10  loaded into the actual slots  2  and  4 , a total of eight pseudo-slots are set.  
      In step S 111  of  FIG. 2 , a display operation is performed in such a manner that the number of pseudo-slots and the content of each pseudo-slot are known. For example, the content shown in  FIG. 4  may be displayed in a display mode as is, or a display may be made by changing only the display mode while maintaining substantially the same content.  
      Next, a description will be given below of a specific technique for analyzing the content in each of the cases where the disk  10  is a CD medium and a DVD medium.  
       FIG. 5  is a flowchart showing the operation procedure for analyzing the content of the disk  10  as a CD medium, in which the details of the operation of step S 104  of  FIG. 2  are shown. When it is determined that the disk  10  is a CD medium, first, the system controller  30  obtains the TOC (Table of Contents) information recorded in the lead-in area of the disk  10  (step S 200 ), and analyzes the track type in the disk (step S 201 ).  
      Next, the system controller  30  determines whether or not the track in the disk is an audio track on the basis of the analysis result (step S 202 ). In the case of an audio track, an affirmative determination is made, and the area corresponding to this track is identified as data for CD-DA (step S 203 ).  
      When the track in the disk is not an audio track, a negative determination is made in the determination of step S 202 . In this case, since the track in the disk is a data track, next, the system controller  30  determines whether or not the area is data for video-CD (step S 204 ). This determination is performed by reading INFO.VCD (MSF=00:04:00 fixed) and by checking whether the identifier is “video-CD”. When the identifier is video-CD, an affirmative determination is made in the determination of step S 204 , and the area corresponding to this track is identified as data for video-CD (step S 205 ).  
      When the identifier is not video-CD, a negative determination is made in the determination of step S 204 . Next, the system controller  30  identifies the content of the file on the basis of the extension contained in the file name (step S 206 ). For example, when the extension of the file name is “.MP3”, this file is identified as an MP3 file. When the extension of the file name is “.WMA”, it is determined that this file is a WMA file. Furthermore, when the extension of the file name is “.BIN”, it is determined that this file is a program update file.  
      In the case of a program update file, since the entire disk  10  is a disk for update data, the disk is not the target for a normal playback operation, and this disk  10  is excluded from the playback target. That is, it is assumed that the disk  10  is loaded into the slot of interest, and the process proceeds to step S 108  of  FIG. 2 , where the determination for the presence or absence of another slot is made.  
      When the analysis of the content corresponding to the audio track or the data track is completed in this manner, next, the system controller  30  determines whether or not another piece of data exists in the same disk  10  (step S 207 ). In this embodiment, there are cases in which data for which the playback method is different as in the disk  10  loaded into the actual slot  2  is recorded in a mixed manner. In this case, an affirmative determination is made, and the determination operation of step S 202  and subsequent steps are performed again on the other data. When another piece of data does not exist, a negative determination is made in step S 207 , and the series of content analysis operations for one disk  10  loaded into the actual slot of interest is completed.  
       FIG. 6  is a flowchart showing the operation procedure for analyzing the content of the disk  10  as a DVD medium, in which the details of the operation of step S 106  of  FIG. 2  are shown. When it is determined that the disk  10  is a DVD medium, first, the system controller  30  searches, for example, folders and files at the root of a UDF (Universal Disk Format) file system and lower folders and files (step S 300 ) for “VIDEO_TS¥VIDEO_TS.IFO”, which is a file for DVD-video, in order to determine whether or not this file exists (step S 301 ). When this file exists, an affirmative determination is made, and the area corresponding to this file is identified as data for DVD-video (step S 302 ).  
      When “VIDEO_TS¥VIDEO_TS.IFO” does not exist, a negative determination is made in step S 301 . Next, the system controller  30  searches for “AUDIO_TS¥AUDIO_TS.IFO”, which is a file for DVD-audio (step S 303 ) in order to determine whether or not this file exists (step S 304 ). When this file exists, an affirmative determination is made, and the area corresponding to this file is identified as data for DVD-audio (step S 305 ).  
      When “AUDIO_TS¥AUDIO_TS.IFO” does not exist, a negative determination is made in step S 304 . Next, the system controller  30  searches for an MP3 file whose extension is “.MP3” (step S 306 ) in order to determine whether or not this file exists (step S 307 ). When this file exists, an affirmative determination is made, and this file is identified as an MP3 file (step S 308 ).  
      When the MP3 file does not exist, a negative determination is made in step S 307 . Next, the system controller  30  searches for a WMA file whose extension is “.WMA” (step S 309 ) in order to determine whether or not this file exists (step S 310 ). When this file exists, an affirmative determination is made, and this file is identified as a WMA file (step S 311 ).  
      In this manner, when the identification of various files is completed (steps S 302 , S 305 , S 308 , and S 311 ), or when the WMA file does not exist and a negative determination is made in the determination of step S 310 , next, the system controller  30  determines whether or not another piece of data (file) exists in the same disk  10  (step S 312 ). In this embodiment, there are cases in which data for which the playback method is different is recorded in a mixed manner as in the disk  10  loaded into the actual slot  4 . In this case, an affirmative determination is made, and the processing of file searching in step S 300  and subsequent steps is performed on the other data again. When no other data exists, a negative determination is made in step S 312 , and the series of content analysis operations for one disk  10  loaded into the actual slot of interest is completed.  
      In this manner, in the disk playback apparatus  1  of this embodiment, the concept of pseudo-slots is introduced in addition to the actual slots. In this pseudo-slot, if the disk  10  differs or the playback method differs even in the same disk  10 , a different slot number is given. Therefore, even when data for which the playback method is different as in a CD-R or a DVD-R and data for which the playback method is different are actually recorded in a mixed manner, it is possible for the user to handle each piece of data within the same disk in a manner similar to individual disks  10  loaded into individual pseudo-slots. Thus, the ease of operation when a playback instruction is given by targeting each piece of data can be improved. Furthermore, since the user can specify each pseudo-slot without being conscious about whether each disk  10  loaded into the disk changer  24  is a CD medium or a DVD medium, the operation can be simplified, and the ease of operation can be improved even more.  
      Next, a description will be given below of a specific example of a playback operation using the above-described pseudo-slots.  FIG. 7  is a flowchart showing the operation procedure when a source is switched for each playback method.  
      When the user specifies the source by operating the operation section  32  (step S 400 ), the system controller  30  extracts and displays the pseudo-slot corresponding to the specified source (step S 401 ). The “source” in this embodiment refers to each piece of the recording content for which the playback method is common, and is not related to the difference in the medium type and the difference in the pseudo-slot number. For example, in step S 400 , when “MP3” is specified as the source, the system controller  30  extracts and displays the pseudo-slots  3  and  4  in which this MP3 is recording content on the basis of the management information shown in  FIG. 4  (step S 401 ).  
      Next, the system controller  30  determines whether or not one of the numbers of the displayed pseudo-slots  3  and  4  is entered by the user (step S 402 ). When no number is entered, a negative determination is made, and thereafter, the system controller  30  determines whether or not the change of the source is instructed by the user (step S 403 ). When the change of the source is not instructed, a negative determination is made, and the determination operation of step S 402  is repeated. When the change of the source is instructed, an affirmative determination is made in the determination of step S 403 , and the process returns to step S 401 , where the processing of the operation for extracting the corresponding pseudo-slot and subsequent steps are performed again.  
      When the pseudo-slot number is entered and an affirmative determination is made in the determination of step S 402 , the system controller  30  performs control for playing back the recorded content corresponding to the specified pseudo-slot (step S 404 ). More specifically, an instruction for taking out the disk  10  from the actual slot corresponding to this pseudo-slot is sent to the disk changer  24 , and instructions for reading and playing back the recorded content from the disk  10  set at a predetermined position are sent to the servo LSI  20  and the digital signal processing section  28 . As a result, in the corresponding playback section within the digital signal processing section  28 , a playback operation for the recorded content that is read is performed, and only the audio data or both the audio data and the video data are reproduced. Then, audio sound corresponding to the audio data is sent from the speaker  40 , and a video signal corresponding to the video data is sent to the display section  42 , whereby a video display is generated.  
       FIG. 8  is a flowchart showing a playback operation in which the usage of the display device  42  is taken into consideration. The system controller  30  determines whether or not the display section  42  is being used in another application (step S 500 ). For example, it is assumed that the disk playback apparatus  1  is incorporated in a vehicle, and when a navigation apparatus (not shown) is operating, the display section  42  is used for a map display. In such a case, an affirmative determination is made in the determination of step S 500 , and the system controller  30  extracts and displays the pseudo-slot corresponding to the source from which only the audio data is reproduced and video data is not reproduced during playback (step S 501 ). In the example shown in  FIG. 4 , the pseudo-slots  2  to  5 , and  8  are extracted. When the display section  42  is not being used in another application, a negative determination is made in the determination of step S 500 , and all the pseudo-slots are extracted and displayed (step S 502 ).  
      Next, the system controller  30  determines whether or not any one of the numbers of the displayed pseudo-slots is entered by the user (step S 503 ). When no number is entered, a negative determination is made, and this determination is repeated. When one of the numbers within the displayed pseudo-slots is entered, an affirmative determination is made in the determination of step S 503 , and the system controller  30  performs control so that the recorded content corresponding to the specified pseudo-slot is played back (step S 504 ).  
       FIG. 9  is a flowchart showing the operation procedure for specifying a source and for randomly playing back the recorded content of one or more pseudo-slots corresponding to the specified source.  
      The system controller  30  determines whether or not the operation section  32  is operated by the user and a random playback of the same source is instructed (step S 600 ). When this instruction is not entered, a negative determination is made, and this determination is repeated. Furthermore, after this instruction is entered and an affirmative determination is made in the determination of step S 600 , when the source is specified by the user (step S 601 ), the system controller  30  extracts the pseudo-slot corresponding to the specified source (step S 602 ). Next, the system controller  30  starts control for performing a random playback by targeting the recorded content of the extracted pseudo-slot (step S 603 ). For example, when “MP3” is specified as the source, the pseudo-slots  3  and  4  are extracted, and a random playback operation is started. In this random playback operation, playback music is randomly selected by targeting all the MP3 files without discriminating the pseudo-slots  3  and  4 , and the playback music is played back in the selected order.  
      As described above, even when a plurality of types of recorded content are recorded on the disk  10 , the playback of each recorded content can be performed by specifying the pseudo-slot number as the identification information corresponding to each recorded content. Thus, the ease of operation when the recorded content is played back using the disk  10  in which a plurality of types of recorded content are recorded in a mixed manner can be improved. Furthermore, by displaying the content of the management information containing the pseudo-slot number corresponding to each recorded content, it becomes possible for the user to confirm the pseudo-slot number corresponding to the recorded content of each disk  10 , and thus, the ease of operation when the pseudo-slot is specified can be improved. Moreover, in this management information, information for specifying the pseudo-slot number and the type of recorded content corresponding to this pseudo-slot number (for example, the name indicating the type of data, such as CD-DA and MP3) is contained. Therefore, it becomes easy for the user to specify the pseudo-slot number and the type of the recorded content corresponding to each pseudo-slot number.  
      As a result of providing the disk changer  24 , it is possible to perform a playback with the pseudo-slot number being specified with respect to one or more pieces of content recorded on each of a plurality of disks  10 . As a result, the ease of operation when the recorded content is played back using one or more disks  10  in which a plurality of types of recorded content are recorded in a mixed manner can be improved.  
      The present invention is not limited to the above-described embodiments, and various modifications are possible within the spirit and scope of the present invention. In the above-described embodiments, a description is given by using as an example a case in which the disk changer  24  is provided with a plurality of actual slots and the disks  10  are loaded into all the actual slots. However, a vacant actual slot to which the disk  10  is not loaded may exist. Furthermore, the present invention can also be applied to a case in which the disk changer  24  is not used and one disk  10  is used. In this case, when various types of data corresponding to a plurality of sources are recorded on one disk  10 , pseudo-slots corresponding to the number of sources are provided.  
      In the above-described embodiments, a description is given of a case in which data corresponding to each source is recorded on the disk  10 . Alternatively, another recording medium may be used. For example, the present invention can also be applied to a case in which data for CD-DA and an MP3 file are stored in advance in a semiconductor memory and a hard disk unit, and these are read therefrom.  
      As examples of a compressed file, an MP3 file and a WMA file are considered. Alternatively, various files compressed using another compression method may be included.