Abstract:
A method and apparatus for reproducing digital contents are discussed. According to an embodiment, the method includes a method of reproducing digital content, including determining whether a sample data is present based on an indication information, the indication information indicating a presence of the sample data; reading a position information specifying a location of a sample data if the sample data is present as a result of the determination, the sample data being a portion of the digital content and reproducible without reproducing the entire digital content; and reproducing the sample data based on the read position information, prior to reproducing the entire digital content.

Description:
[0001]     This application is a continuation of co-pending U.S. application Ser. No. 10/743,036 filed on Dec. 23, 2003, which is a continuation application of U.S. application Ser. No. 09/783,987 filed on Feb. 16, 2003 (now U.S. Pat. No. 6,766,103), The entire contents of each of these applications are herein fully incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a method for managing information on representative audio for audio tracks recorded in a rewritable recording medium and for reproducing the representative audio to have a user know easily what contents a recorded audio track has.  
         [0004]     2. Description of the Related Art  
         [0005]     A disk-type recording medium such as a compact disk (CD) can store high-quality digital audio data permanently, so that it is very popular recording medium. Recently, a digital versatile disk (referred as ‘DVD’ hereinafter) has been developed as a new disk-type recording medium. A DVD can store much larger size than a CD, that is, high-quality moving picture or audio data is recorded in a DVD for much longer time. Therefore, a DVD will be used widely in the near future.  
         [0006]     There are three types in a DVD, DVD-ROM for read-only, DVD-R for write-once, and DVD-RAM or DVD-RW for rewritable. For a rewritable DVD, the standardization of data writing format is in progress.  
         [0007]      FIG. 1  is a block diagram of an optical disk device for recording and reproducing video and/or audio data to/from a rewritable disk according to a related art.  
         [0008]     The disk device configured as in  FIG. 1  comprises an optical pickup  2  reading a signal recorded in a rewritable DVD  1  or writing a data stream processed into a writable signal in the rewritable DVD  1 ; a reproduced signal processor  8  restoring the read signal into compressed digital data; a decoder  9  decoding the compressed digital data into original data; a sampler  5  digitizing an inputted analog signal at a predetermined sampling rate; an encoder  4  encoding the digitized data into MPEG-, LPCM-, or AC3-formatted data; a writing signal processor  3  converting data from the encoder  4  into signals adequate to be written; a controller  6  controlling all elements to conduct a recording or reproducing operation; and a memory  7  for storing data temporally. These elements are operatively coupled.  
         [0009]     If an analog signal is applied to the disk device of  FIG. 1 , the sampler  5  samples the analog signal at the predetermined sampling rate, and applies the sampled digital data to the encoder  4 . The encoder  4  encodes a block of sampled data into compressed or non-compressed data of pre-specified format, for example, MPEG format for compressed or LPCM format for non-compressed, and the writing signal processor  3  converts bit trains of the formatted data into writing pulses which are applied to the pickup  2 . Then, the pickup  2  writes bit information associated with the writing pulses on the recording surface of the rewritable DVD  1 .  
         [0010]     The audio data recorded continuously from recording start to stop is called a ‘track’ which is a logical unit and is different from a physical spiral track formed in a rewritable disk. If the recording operation stops after a single audio song provided from a microphone or broadcast signal has been recorded, the recorded song corresponds to a track. However, a track may contain several recorded songs if several songs are recorded continuously at one time.  
         [0011]     The recorded audio songs, that is, all tracks are indexed by a track set information as shown in  FIG. 2 . Information for a track recorded newly is inserted in the track set information and information for an erased track is deleted from the track set information.  
         [0012]     A part of a track (PoT) only specified within an audio track is able to be reproduced. Such a partial reproduction is initiated through selecting a play list which defines an audio track playback sequence. That is, a play list identifies an ordered list of predetermined songs or tracks to be played back for the user&#39;s enjoyment.  
         [0013]     After a track has been recorded or edited, cell information (CI) is created to refer to full or part of the track. The created cell information is written in an original or a user-defined program chain information (PGCI). A play list is associated with a PGCI through the number of PGCI.  
         [0014]     Therefore, if a play list defined by a user or created automatically after recording is selected, the controller  6  searches for a PGCI that the selected play list refers to, and reads out location information of full or part of each track written in CIs belonging to the discovered PGCI. Finally, the controller  6  moves the pickup  2  to all locations sequentially, and conducts a reproduction of the tracks or songs according to the selected  
         [0015]     However, since a rewritable DVD is an extremely high-capacity storage device and numerous audio tracks can be recorded in it, it becomes very difficult and time consuming to find a track containing a desirable song or sound after many audio tracks have been recorded.  
       SUMMARY OF THE INVENTION  
       [0016]     Accordingly, it is an object of the present invention to provide a method and system for locating a particular track by providing and playing back representative audio sections, which overcome the above-described problems and disadvantages associated with the related art.  
         [0017]     It is another object of the present invention to provide a method for managing information on representative audio for audio tracks recorded in a high-capacity storage medium and for reproducing the representative audio to help a user find a desirable audio track easily.  
         [0018]     A method of managing information on audio tracks recorded in a rewritable recording medium according to an embodiment of the present invention, receives a command specifying a representative audio section for a full or a partial audio track recorded in the rewritable recording medium, and writes location information on the specified representative audio section in cell information related with the full or the partial audio track.  
         [0019]     A method of reproducing audio data recorded in a rewritable recording medium according to an embodiment of the present invention, receives a command requesting representative audio reproduction for audio tracks recorded in the rewritable recording medium, reads location information written in cell information related with full or partial tracks, and searches for and reproduces a data block specified by the read location information after checking whether the read location information is about a representative audio section. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]     The accompanying drawings, which are included to provide a further understanding of the invention, illustrate the preferred embodiments of this invention, and together with the description, serve to explain the principles of the present invention.  
         [0021]     In the drawings:  
         [0022]      FIG. 1  is a block diagram of a general optical disk device recording and reproducing video or audio data to/from a rewritable disk;  
         [0023]      FIG. 2  shows a structure of audio tracks and related play information written in a rewritable disk;  
         [0024]      FIG. 3  shows a hierarchical structure of real time recording audio manager information for audio tracks recorded in a rewritable disk, in which the present invention is implementable;  
         [0025]      FIG. 4  shows a structured program chain including cell information in which information on a representative audio section is written according to an embodiment of the present invention;  
         [0026]      FIG. 5  shows an example where representative audio sections are specified for recorded audio tracks according to the present invention;  
         [0027]      FIG. 6  shows a structured program chain including cell information in which information on a representative audio section is written in different format from  FIG. 4  according to an embodiment of the present invention;  
         [0028]      FIG. 7  shows another example where representative audio sections are specified for recorded audio tracks according to the present invention;  
         [0029]      FIG. 8  is an example of screen data displaying several play lists, each being linked with recorded audio tracks according to the present invention; and  
         [0030]      FIG. 9  is a flowchart illustrating a method of reproducing data according to an embodiment of the invention.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0031]     In order that the invention may be fully understood, preferred embodiments thereof will now be described with reference to the accompanying drawings.  
         [0032]      FIG. 3  shows a hierarchical structure of real time recording audio manager information (RTR_AMGI) for audio tracks recorded in a rewritable disk such as a rewritable DVD, in which the present invention is implementable.  
         [0033]     As shown in  FIG. 3 , the RTR_AMGI contains an audio manager information management table ‘AMGI_MAT’ and a play list search pointer table ‘PL_SRPT’. The play list search pointer table includes play list search pointer table information ‘PL_SRPTI’ and one or more play list search pointers ‘PL_SRP #n’.  
         [0034]     Each play list search pointer ‘PL_SRP #n’ has the number of an associated program chain (PGC) which refers to one program chain (PGC) structured as shown in  FIG. 4  or  FIG. 6  according to the embodiments of the present invention.  
         [0035]     After an audio signal has been recorded in a rewritable DVD through the writing signal processor  3 , the controller  6  creates CI related with the recorded track. The created CI has start and end position information of the recorded track in the field of audio cell general information ‘A_C_GI’, and it is written in a user-defined PGC or an original PGC, which is created automatically after recording, according to a user&#39;s choice. After several audio tracks have been recorded, several associated CIs are created and then written in a PGC together with location information about each CI as shown in  FIG. 4  according to the present invention.  
         [0036]     According to the present invention, the CI includes audio cell information which contains a plurality of cell entry point information ‘A_C_EPI #n’ besides the audio cell general information ‘A_C_GI’. The audio cell entry point information includes, according to one embodiment, a type field ‘EP_TY’ and fields ‘EP_RA_S_PTM’ and ‘EP_RA_E_PTM’ containing the start and end location information on its representative audio section. A representative audio section refers to herein as a short characteristic or representative portion of an audio track/song which may be designated by a user. By playing back such representative audio sections and listening to only the representative audio sections (and not the entire songs in the play list), the user can quickly locate the song or track that the user desires to access.  
         [0037]     In one embodiment, the cell entry point information ‘A_C_EPI #n’ contains different information according to its type defined in the type field ‘EP_TY’. The representative audio location information (i.e., location information on a representative audio section) is written in this cell entry point information with a bit value, e.g., ‘0001XXXX’ (e.g., ‘X’ means ‘don&#39;t-care’) in the type field ‘EP_TY’. The cell entry point information with the bit value ‘0001XXXX’ in the type field contains start and end position information of representative audio section in the fields ‘EP_RA_S_PTM’ and ‘EP_RA_E_PTM’, respectively. The position information is expressed in the unit of presentation time (PTM).  
         [0038]     In this example, each of the start and end position information of the representative audio section is contained in 6 bits.  
         [0039]     If the type field (EP_TY) of the cell entry point information has a value of ‘0110XXXX’, it means that the cell entry point information has single position information only indicating a random accessible point and no representative audio section.  
         [0040]     In the case that numerous audio tracks have been recorded in the rewritable DVD  1 , if a user specifies some representative audio sections for all or some audio tracks in an edit mode, the controller  6  obtains location information for the specified representative audio sections, and writes the obtained representative audio location information in respective cell entry information fields of cell information corresponding to audio tracks whose representative audio sections are specified.  
         [0041]     A representative audio data may be newly generated from a user&#39;s voice, specific sound, and so on, and then recorded instead of being specified within a recorded audio track.  
         [0042]      FIG. 5  shows an example where representative audio sections are specified for recorded audio tracks according to an embodiment of the present invention. In the example of  FIG. 5 , the cell entry point defined in  FIG. 4  is used to specify start and end position of each representative audio section ‘RA_ENT #n’, and an audio track is marked as an audio object ‘AOB #n’ in the drawing.  
         [0043]     Explaining the example of  FIG. 5 , three audio tracks, that is, three audio objects (AOBs) have been recorded, and three CIs associated with three audio tracks have been written in and associated with an original program chain ‘ORG_PGC’ which has been created after the initial recording. The controller  6  has created CI ‘Cell  4 ’ referring to a partial track ‘UD_TRK’ specified within the third track ‘AOB # 3 ’ and has written the created CI ‘Cell  4 ’ in a user-defined program chain ‘UD_PGC’ since the partial track ‘UD_TRK’ is chosen in the edit mode by the user.  
         [0044]     The created CI ‘Cell  4 ’ also contains start and end position of a specified representative audio section ‘RA_ENT # 4 ’ for the user-defined partial track ‘UD_TRK’. In the example of  FIG. 4 , the third full track ‘AOB # 3 ’ and the user-defined partial track ‘UD_TRK’ have the same representative audio section marked as ‘RA_ENT # 3 ’, ‘RA_ENT # 4 ’, however, the representative audio section of the user-defined partial track may be specified differently from that of the full track the partial track belongs to.  
         [0045]     In accordance with another embodiment of the present invention, instead of using start and end position as location information of a representative audio section as depicted in  FIG. 4 , it is also possible to use start position and duration to specify a representative audio section.  FIG. 6  shows such an example of a structured program chain including a cell entry point having fields of entry type, start position, and duration according to another embodiment of the present invention. The number of audio frames included in a specified representative audio section may be written in the duration field instead of time length.  
         [0046]      FIG. 7  shows an example where representative audio sections are specified differently using the structure of  FIG. 6 , from the example of  FIG. 5  according to the present invention. The example of  FIG. 7  shows that CI indicates the length of a representative audio section with the duration information ‘RA_DUR’ shown in  FIG. 6  instead of using the end position information ‘EP_RA_E_PTM’ which is a field of a cell entry point given in  FIG. 4 .  
         [0047]     Hereinafter, described is a method of reproducing representative audio sections related with recorded audio tracks according to an embodiment of the present invention. This method is discussed as being implemented in the system of  FIG. 1 ; however, the present method can be implemented in other systems.  
         [0048]     Particularly, when a rewritable DVD  1  is inserted into the disk device of  FIG. 1 , the controller  6  reads out management information for all audio tracks recorded in the rewritable DVD  1  and stores them in the memory  7 . If a user requests reproduction of the inserted disk, the controller  6  constructs screen data for selecting a play list based on the real time recording audio manager information (RTR_AMGI) stored in the memory  7 , and outputs the constructed screen data to be displayed onto a connected displaying device such as a digital television or an equipped LCD as shown in  FIG. 8 . At the same time, the controller  6  builds a cursor data and overlaps it with the screen data.  
         [0049]     According to the interpreted movement data of the cursor received from an input device such as a remote controller, the controller  6  moves the cursor position until the selection of a play list is made. If a play list among presented play lists is chosen, the controller  6  accesses program chain information indicated by a PGC number written in the selected play list, and reads all CIs written in the accessed program chain information.  
         [0050]     For example, the controller  6  reads three CIs associated with the three tracks ‘AOB # 1 ’, ‘AOB # 2 ’, and ‘AOB # 3 ’ if the selected play list is related with an original program chain shown in  FIG. 5  or  7 . After reading all CIs and if a command for a reproduction of representative audio sections is given (which will be discussed below) , the controller  6  checks whether or not each CI includes location information on a representative audio section, and reads the representative audio location information identifying the start and end position ( FIG. 4 ) or the start position and its length of the representative audio section. For the recording example of  FIG. 5  or  7 , the location information about the three representative audio sections ‘RA_ENT # 1 , # 2 , and # 3 ’ is read out.  
         [0051]     Referring to the read location information on the representative audio sections, the controller  6  moves the pickup  2  to the representative audio sections sequentially. At each representative audio section, audio data written within each section is detected by the pickup  2 , and is processed into audible sound through the decoder  9  and the reproduced signal processor  8  until the reproduction point arrives at the end position indicated by each cell entry point. This representative audio reproducing operation is conducted up to the audio section indicated by the last CI.  
         [0052]     If a user selects a play list related with a user-defined program chain in the above selecting step, the representative audio section ‘RA_ENT # 4 ’ indicated by the CI ‘Cell  4 ’ will be searched and reproduced in the recorded example of  FIG. 5  or  7 .  
         [0053]     In the above-explained reproduction operation, it is considered that there is no representative audio for an audio track if the type value of a cell entry point written in CI related with the track is not ‘0001XXXX’. In this case, that track is skipped without reproducing any representative audio data.  
         [0054]     In the recorded example of  FIG. 5  or  7 , a user-defined program chain has a single partial audio track. However, a user-defined program chain can refer to many partial audio tracks by including a plurality of CIs which have respective representative audio location information to access each partial track. For a user-defined program chain referring to a plurality of partial tracks, the controller  6  reproduces representative audio sections specified in CIs sequentially as explained above for the case of an original PGC.  
         [0055]     While a sequential reproduction of representative audio sections is conducted as discussed herein, the previous or the next representative audio section may be requested to be reproduced from a user through an input device such as a remote controller. If such a request is entered, the controller  6  checks the information written in the previous or the next CI, moves the pickup  2  to the start position pointed by a cell entry point of the previous or the next CI, and reproduces representative audio data within the track section defined by the cell entry point.  
         [0056]     In addition, if a track number is entered from a user, the controller  6  searches a program chain being reproduced for CI whose index number is equal to the entered track number, and reproduces a representative audio section indicated by a cell entry point of the discovered CI.  
         [0057]     The method of reproducing representative audio sections as discussed above is illustrated generally in  FIG. 9  according to an embodiment of the invention.  
         [0058]     It is also possible according to an embodiment of the present invention to replay from a head of a representative audio section being reproduced if ‘replay’ is commanded. This function is provided so that a representative audio section of a full or partial track is reproduced repeatedly as far as the user wants.  
         [0059]     According to the present invention, various aforementioned methods of representative audio reproduction may be commanded through a remote controller as explained above. In one embodiment, a remote controller is equipped with a hot button or switch for ‘Representative Audio’. When this hot button is pressed once, which means turn ‘ON’ the representative audio reproduction, the above-explained sequential representative audio reproduction of the present invention is conducted. If there is a specific program chain having been selected prior to the actuation of the hot button, the sequential representative audio reproduction is conducted for audio tracks belonging to the selected program chain. However, if there is no specific program chain having been selected prior to the actuation of the hot button, then the representative audio reproduction is conducted for an original program chain referring to a lately-recorded audio track.  
         [0060]     If the hot button for ‘Representative Audio’ is pressed again, which means turn ‘OFF’ the representative audio reproduction, the sequential representative audio reproduction being conducted is terminated, and then a normal audio track reproduction begins from a head of an audio track including the terminated representative audio section.  
         [0061]     In one embodiment, if the user notices that a representative audio being played back at present is related with an audio track that the user has been searching for, then he or she presses the hot button for ‘Representative Audio’ again, which in turn causes the entire audio track of the current representative audio section to be played back.  
         [0062]     The above-explained representative audio reproducing method for recorded audio tracks enables a user to find a desirable audio track easily and quickly among multiple audio tracks recorded in a high-capacity recording medium such as a rewritable DVD.  
         [0063]     The foregoing is provided only for the purpose of illustration and explanation of the preferred embodiments of the present invention, so changes, variations and modifications may be made without departing from the spirit and scope of the invention.