Abstract:
When a media player reproduces a content identical to a content being reproduced by a renderer, the media player obtains, from the media renderer, content information of the content being reproduced by the media renderer. The media player then obtains a content list from a server, and specifies a content having content information identical to content information received from the media renderer as well as its position in the content list. As a result, a user can specify the content being reproduced by the media renderer, and can start reproduction without operating the media player and searching for the content.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an audio output apparatus for reproducing a content in a home network. 
         [0003]    2. Description of the Related Art 
         [0004]    In recent years, the following forms are becoming widespread. One form is such that a home network is structured, and music, still images, and moving image contents (hereinafter, contents) saved in a digital media server (hereinafter, DMS) are reproduced by a digital media renderer (hereinafter, DMR) according to an instruction of a digital media controller (hereinafter, DMC). Another form is such that a digital media player (hereinafter, DMP) obtains contents from the DMS and reproduces the contents. In a DLNA (registered trademark: hereinafter, DLNA) standard, functions of the DMP, DMS, DMR and DMC are defined so that specifications of communication and operations therebetween are determined. In the following description, the contents are music contents. 
         [0005]    When the contents saved in the DMS are reproduced by an apparatus having the DMP function, a user views the contents of the DMS displayed on a display device connected to the DMP, and selects a content desired to be reproduced so as to instruct reproduction. The DMP requests the DMS for content data instructed to be reproduced by the user, and starts the reproduction. 
         [0006]    On the other hand, when the contents saved in the DMS are reproduced by the apparatus having the DMR function, the user selects one DMS from a plurality of DMSs displayed on the display device connected to the DMC. Further, the user specifies one DMR from a plurality of DMRs as a reproducing apparatus in the DMC. The user specifies a content to be reproduced from the contents of the DMS displayed in the DMC. As a result, the instruction for reproducing contents is transmitted from the DMC to the DMR, and the DMR connects to the DMS specified by the DMC, and obtains content data of the DMS so as to reproduce the content data. 
         [0007]    Further, some audio output apparatuses compatible with DLNA that can function as the DMP and also as the DMR are present. The audio output apparatus that can use the DMP function and the DMR function simultaneously has two or more audio output paths and audio amplifiers. A speaker for outputting contents reproduced by the DMR, and a speaker for outputting contents reproduced by the DMP are installed in separate rooms, and the reproduction by means of the DMR and the reproduction by means of the DMP can be simultaneously performed. At this time, a content that is identical to a content being reproduced by the DMR is desired to be easily reproducible by using the DMP. 
         [0008]    When the content being reproduced by the DMR is automatically specified by the DMP and is reproduced, the DMP has a problem that even when a content URL (location information about the content of DMS) utilized by the DMR is used, the content that is identical to the content being reproduced by the DMR cannot be reproduced. This is because the content URL of the DMS used for the reproduction by the DMR is specified by the DMC, and the DMP cannot use this directly. 
         [0009]    Further, the DMP cannot automatically specify a location including hierarchical information of the DMS in the content being reproduced by the DMR. Therefore, in the DMP, the user cannot automatically obtain a higher folder of the content being reproduced by the DMR. The higher folder is an album folder or an artist folder to which the content being reproduced by the DMR belongs. The URL of the content, which is received by the DMR when the DMC instructs the reproduction, does not include at all information or the like about a higher folder to which the content belongs. Therefore, the user operates the DMP with reference to the artist name or the album name of the content being reproduced by the DMR, and should search for the artist folder or the album folder including the content being reproduced by the DMR. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention is devised in order to solve the above problems, and an object thereof is that a DMP reliably specifies and reproduces a content, the content identical to a content being reproduced by a DMR, and the DMP specifies a folder of a DMS including the content identical to the content being reproduced by the DMR, and automatically moves to that folder so as to reproduce the content. 
         [0011]    An audio output apparatus of the present invention comprises: a media renderer for obtaining and reproducing a content of a server based on a control command transmitted from a controller according to a user&#39;s operation; and a media player for obtaining and reproducing the content of the server based on an instruction input by the user. The media renderer includes a unit for receiving location information of the content of the server from the controller and obtaining the content from the server based on the location information so as to reproduce the content. The media player includes a unit for obtaining a content list of the server selected by the user&#39;s operation, a reproducing unit for obtaining the content selected from the content list by the user&#39;s operation from the server so as to reproduce the content, a unit for accepting an identical content reproducing instruction that is an instruction for reproducing the content identical to the content being reproduced by the media renderer, a content information obtaining unit for obtaining, from the media renderer, content information of the content being reproduced by the media renderer when the identical content reproducing instruction is accepted, and an identical content specifying unit for searching the content list for a content identical to the content being reproducing by the media renderer based on the content information and specifying a position of the content in the content list, and the reproducing unit reproduces the content specified by the identical content specifying unit. 
         [0012]    When the media player accepts an instruction for reproducing a content that is identical to the content being reproduced by the media renderer, the media player obtains, from the media renderer, information about a content being reproduced by the media renderer. Further, the media player obtains a content list from the server and specifies from the content list a content having the content information identical to the content information received from the media renderer. As a result, the user can specify the content being reproduced by the media renderer from the content list, and can reproduce the content without the user&#39;s operation of the media player to search for the content from the server. 
         [0013]    Preferably the audio output apparatus further comprising: a first output section for outputting content data being reproduced by the media player to a first content receiving device installed in a first room; and a second output section for outputting the content data being reproduced by the media renderer to a second content receiving device installed in a second room. When the media player accepts the identical content reproducing instruction, the reproducing unit outputs the content specified by the identical content specifying unit to the first content receiving device. 
         [0014]    The media renderer reproduces a content in the content receiving device arranged in a second room, and simultaneously, the media player can reproduce a content identical to the content being reproduced by the media renderer from the content receiving device arranged in a first room. 
         [0015]    Preferably the content information is meta-information of the content, the media player further includes a determining unit for comparing the meta-information of each of the contents in the content list with the meta-information obtained from the media renderer to determine whether the meta-information match with each other when the identical content reproducing instruction is accepted, and the identical content specifying unit specifies a position of the content whose meta-information is determined as matching in the content list. 
         [0016]    The media player searches for the content identical to the content being reproduced by the media renderer using meta-information about the content. As a result, the user can specify the content being reproduced by the media renderer from the content list and can start the reproduction without operating the media player to search for the content from the server. 
         [0017]    Preferably the content information includes folder meta-information as the meta-information about one or a plurality of content folders and content meta-information as the meta-information about the content included in a content folder in a lowest hierarchical level. The media player further includes a folder list obtaining unit for obtaining a content folder list from the server, a content folder determining unit for comparing the meta-information about the content folders in the content folder list with the folder meta-information obtained from the media renderer to determine whether the meta-information match with each other, an identical content folder specifying unit for specifying a position of the content folder whose meta-information is determined as matching in the folder list, and a content path storage unit for storing the position of the content folder specified by the identical content folder specifying unit into a content path, the determining unit compares the meta-information about the contents included in the lowest content folder with the content meta-information obtained from the media renderer to determine whether the meta-information match with each other, the identical content specifying unit specifies a position of the content whose meta-information is determined as matching in the content list, the content path storage unit stores the position of the content specified by the identical content specifying unit into the content path, the reproducing unit moves to the content folder of the server specified by the content path to reproduce the content. 
         [0018]    The media player specifies the content identical to the content being reproduced by the media renderer based on the meta-information about the folder and the meta-information about the content. Therefore, the media player can specify the content as well as path information of the folder on the server. As a result, in the media player, the user can easily obtain an album folder and an artist folder including the content being reproduced by the media renderer. 
         [0019]    Preferably the media player further includes a content meta-information missing determining unit for determining whether the content information includes the content meta-information, and a content data obtaining unit for, when the identical content reproducing instruction is accepted, obtaining from the media renderer at least part of the content data of the content being reproduced by the media renderer, when the determination is made that the content meta-information is missing, at least part of the content data of the respective contents included in the lowest content folder is obtained from the server, the determining unit compares a reproducing waveform of the content data of the content obtained from the server with a reproducing waveform of the content data obtained from the media renderer to determine whether the content data match with each other, and the identical content specifying unit specifies a position of the content whose content data is determined as matching in the content list. 
         [0020]    According to the present embodiment, even when the meta-information about the content cannot be obtained from the media renderer, the media player compares the content data of the content in the content folder and the content data of the content being reproduced by the media renderer, so that the media player can uniquely specify the content being reproduced by the media renderer. 
         [0021]    A media renderer program stored on a non-transitory computer readable medium causes the audio output apparatus to execute the respective units of the media renderer in the audio output apparatus. 
         [0022]    A media player program stored on a non-transitory computer readable medium causes the audio output apparatus to execute the respective units of the media player in the audio output apparatus. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a connection diagram of an audio output apparatus, a DMS, and a DMC according to a preferred embodiment of the present invention; 
           [0024]      FIG. 2  is a block diagram illustrating an apparatus according to the preferred embodiment of the present invention; 
           [0025]      FIG. 3  is a diagram illustrating a structure of contents to be managed by a DMS; 
           [0026]      FIG. 4  is a flowchart illustrating a process in a control section of a DMC; 
           [0027]      FIG. 5  is a flowchart illustrating a process in a control section of a DMR; 
           [0028]      FIG. 6  is a flowchart illustrating a process in a control section of a DMP; 
           [0029]      FIG. 7  is a flowchart illustrating a process in the control section of the DMR; 
           [0030]      FIG. 8  is a flowchart illustrating a process in the control section of the DMP; 
           [0031]      FIG. 9  is a diagram illustrating a structure of contents to be managed by the DMS; 
           [0032]      FIG. 10  is a flowchart illustrating a process in the control section of the DMR; 
           [0033]      FIG. 11  is a flowchart illustrating a process in the control section of the DMP; 
           [0034]      FIG. 12  is a diagram illustrating a structure of contents to be managed by the DMS; 
           [0035]      FIG. 13A  is a flowchart illustrating a process in the control section of the DMP; 
           [0036]      FIG. 13B  is a flowchart illustrating a process in the control section of the DMP; and 
           [0037]      FIG. 14  is a flowchart illustrating a process in the control section of the DMP. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0038]    A communication apparatus according to preferred embodiments of the present invention will be concretely described below with reference to the drawings, but the present invention is not limited to these preferred embodiments.  FIG. 1  is a connection diagram of an audio output apparatus, a DMS, and a DMC according to the preferred embodiment of the present invention. 
         [0039]    An audio output apparatus  100  that has functions of a DMR  100 A 1  and a DMP  100 A 2 , a DMC  200 , and a DMS  300  are connected to a network. A DMP speaker  101  and a DMR speaker  102  are connected to the audio output apparatus  100 . In a home network in  FIG. 1 , the audio output apparatus  100  and the DMP speaker  101  are installed in a main room, and the DMC  200  and the DMR speaker  102  are installed in a zone  2  room. The DMS  300  is installed in any one of the main room and the zone  2  room, or any place other than the main room and the zone  2  room. Since the DMR  100 A 1  and the DMP  100 A 2  are incorporated into the one audio output apparatus  100 , they can communicate with each other without using the network, and data can be exchanged and referred to by interprocess communication and a shared memory. Further, the audio output apparatus  100  can output a sound to the DMP speaker  101  and the DMR speaker  102  simultaneously. The audio output apparatus is, for example, an AV amplifier. 
         [0040]    The DMR  100 A 1  receives a reproducing instruction from the DMC  200 , and connects to the DMS  300  according to the reproducing instruction. The DMR  100 A 1  obtains content data from the DMS  300  so as to reproduce the content data. When the DMR  100 A 1  receives the reproducing instruction from the DMC  200 , only the URL of the content of the DMS  300  is specified. That is, the DMR  100 A 1  does not have a folder structure and hierarchical information of the DMS  300  unlike the DMP  100 A 2 , described later. When the DMR  100 A 1  completes the reproduction of the content specified by the DMC  200 , the completion is notified to the DMC  200 . The DMC  200  transmits, to the DMR  100 A 1 , a URL of a content to be reproduced next. The DMR  100 A 1  accesses the URL of the content to be transmitted from the DMC  200 , and reproduces the content. 
         [0041]    The DMP  100 A 2  browses a folder list stored in the DMS  300 . The folder is a storage place including reproducible contents, and the folder list is a row of folders. The folder includes a plurality of types of folders such as an artist folder, an album folder, a genre folder, and an all track folder. The artist folder includes an album folder list, and the album folder includes reproducing contents. For example, the user selects a specific artist from an artist folder list, and obtains the album list included in the artist folder. The user selects a specific album from the album list, and obtains a content list in the album. The user specifies a content from the content list. The DMP  100 A 2  reproduces the specified content. After the reproduction of the content is completed, the DMP reproduces next content included in the album folder or the artist folder including the reproduced content. 
         [0042]      FIG. 2  is a block diagram illustrating respective devices connected to the network. The audio output apparatus  100  has a control section  100 A, a storage section  100 B, a communication section  100 C, a DMR audio output section  100 D, a DMP audio output section  100 E, an operating section  100 F, and a display section  100 G. 
         [0043]    The control section  100 A controls the audio output apparatus  100  and is, for example, a microcomputer or a CPU. The control section  100 A further has a DMR program  100 A 1  and a DMP program  100 A 2 . The DMR program  100 A 1  is a program executed by the control section  100 A when the audio output apparatus  100  operates as the DMR. The DMP program  100 A 2  is a program executed by the control section  100 A when the audio output apparatus  100  operates as the DMP. The control section  100 A can execute the DMR program  100 A 1  and the DMP program  100 A 2  simultaneously. Hereinafter, when they do not have to be particularly clarified as a program and only a function thereof is indicated, the DMR program  100 A 1  is called the DMR  100 A 1 , and the DMP program  100 A 2  is called the DMP  100 A 2 . 
         [0044]    The storage section  100 B is, for example, a ROM or a RAM. The storage section  100 B has a content data buffer  100 B 1 . The content data buffer  100 B 1  is a buffer for storing all or part of content data obtained from the DMS  300  for reproduction by the DMR  100 A 1 . 
         [0045]    The communication section  100 C has a function for transmitting/receiving data with the DMC  200  and the DMS  300  via the network. 
         [0046]    When the audio output apparatus  100  function as the DMR, the DMR audio output section  100 D outputs a sound to the DMR speaker  102  of  FIG. 1 . The DMR audio output section  100 D is configured by a decoder, a DAC, and an audio signal amplifying section. When the audio output apparatus  100  functions as the DMP, the DMP audio output section  100 E outputs a sound to the DMP speaker  101  of  FIG. 1 . The DMP audio output section  100 E is configured by a decoder, a DAC, and an audio signal amplifying section. As described above, since the audio output apparatus  100  can simultaneously execute the DMR program  100 A 1  and the DMP program  100 A 2 , a sound can be simultaneously output from the DMR audio output section  100 D and the DMP audio output section  100 E. The sounds that are output from both the output sections may be the same as or different from each other. 
         [0047]    The operating section  100 F is a section for receiving an input from an input button provided to a main body of the audio output apparatus  100  and a remote control code transmitted from a remote controller attached to the audio output apparatus  100 . A command received from the user by the operating section  100 F is analyzed and executed in the control section  100 A. 
         [0048]    The display section  100 G displays information about a content being reproduced by the audio output apparatus  100 . The display section  100 G is, for example, an FL tube or an OSD (onscreen display). 
         [0049]    The DMC  200  includes a control section  200 A, a storage section  200 B, a communication section  200 C, an operating section  200 D and a display section  200 E. 
         [0050]    The control section  200 A controls the DMC  200 , and is, for example, a microcomputer or a CPU. The storage section  200 B is, for example, a ROM or a RAM. The communication section  200 C communicates with the AV amplifier  100  and the DMS  300  via the network. The operating section  200 D is a part that accepts an operation for the DMC  200  and receives an input from a button arranged on the DMC  200  and a remote control code transmitted from a remote controller attached to the DMC  200 . The display section  200 E displays a content list obtained from the DMS  300  by the DMC  200 , a reproducing state of a content received from the DMR  100 A 1 , and a list of reproducing devices having the DMR function on the network. 
         [0051]    The DMS  300  includes a control section  300 A, a storage section  300 B, a communication section  300 C, and an HDD  300 D. 
         [0052]    The control section  300 A controls the DMS  300 , and is, for example, a microcomputer or a CPU. The control section  300 A executes a process for transmitting a content list and content data in response to a content list obtaining request from the DMC  200  or the DMP  100 A 2 , and a content data obtaining request from the DMR  100 A 1  or the DMP  100 A 2 . The storage section  300 B is, for example, a ROM or a RAM. The communication section  300 C communicates with the audio output apparatus  100  and the DMC  200  via the network. The HDD  300 D is a storage medium for storing music contents or the like. 
         [0053]      FIG. 3  illustrates one example of the content list stored in the HDD  300 D of the DMS  300 . In the DMS  300 , contents are hierarchically managed, and a folder “All Tracks” including all content data stored in the HDD  300 D exists below the highest hierarchical level “musicRoot”. An identification number (hereinafter, content ID) is set for the folder “All Tracks”. Contents are arranged in a lower hierarchical level below the folder “All Tracks” (Track A 11 , Track A 12 , and the like). Content IDs are also given to the respective contents. The DMP  100 A 2  can specify contents using the contents IDs. 
         [0054]    The control section  100 A of the audio output apparatus  100  in the present invention first starts to execute the DMR program  100 A 1 . The DMR  100 A 1  obtains from the DMS  300  a content instructed to be reproduced by the DMC  200 , and starts the reproduction. The content is reproduced from the DMR speaker  102  installed in the zone  2  room. The control section  100 A of the audio output apparatus  100  then executes the DMP program  100 A 2  according to a user&#39;s operation or the like. The user instructs the DMP  100 A 2  to reproduce the content identical to the content being reproduced by the DMR  100 A 1 . The control section  100 A specifies the content identical to the content being reproduced by the DMR  100 A 1 , and starts the reproduction in the DMP  100 A 2 . Content data reproduced by the DMP  100 A 2  is output from the DMP speaker  101  of the main room. The DMP  100 A 2  continues the reproduction according to the content list shown in  FIG. 3 . 
         [0000]    [First Embodiment in which DMP Starts Reproduction of Content Identical to that of DMR] 
         [0055]      FIG. 4  is a flowchart illustrating a process executed by the DMC  200  in the first embodiment when the DMP  100 A 2  is instructed to reproduce the content identical to that of the DMR  100 A 1 .  FIG. 5  is a flowchart illustrating the DMR  100 A 1  in the first embodiment.  FIG. 6  is a flowchart illustrating the DMP  100 A 2  according to the first embodiment. 
         [0056]    According to the present embodiment, when the DMP  100 A 2  receives an instruction for reproducing the content identical to that of the DMR  100 A 1 , the DMP  100 A 2  specifies a content having content information identical to the content information of the content being reproduced by the DMR  100 A 1  from the contents stored in the DMS  300 . 
         [0057]    The DMC  200  in the flowchart of  FIG. 4  searches for the DMS  300  on the network and displays the searched DMS  300  on the display section  200 E. When a plurality of devices having the DMS function is present on the network, all the DMSs  300  are displayed on the display section  200 E. Then, one DMS  300  is selected in the DMC  200  by the user&#39;s operation (S 101 ). 
         [0058]    The DMC  200  connects to the DMS  300  selected in S 101 , and obtains and displays a list of the contents stored and managed in the DMS  300  (S 102 ). The contents are displayed on the display section  200 E as the content list positioned in the “All Tracks” folder or in a lower hierarchical level below the “All Tracks” folder in  FIG. 3 . 
         [0059]    The DMC  200  searches for the DMR  100 A 1  on the network, and displays the searched DMRs  100 A 1  on the display section  200 E. The user specifies one DMR  100 A 1  from the DMR list in the DMC  200  (S 103 ). 
         [0060]    The DMC  200  specifies a content to be reproduced from the content list displayed by the user&#39;s operation in S 102  (S 104 ). 
         [0061]    The DMC  200  sets URL of the content specified in S 104  to the DMR  100 A 1  (S 105 ). The URL of the content is location information about the content selected by the user on the DMS  300 . The DMR  100 A 1  accesses to the content URL transmitted from the DMC  200  by the process in S 105 , and obtains the content data from the DMS  300  so as to reproduce the content data. 
         [0062]    The DMC  200  determines whether the DMR  100 A 1  completed the reproduction of an on-reproducing track (S 106 ). When the reproduction of the currently on-reproducing content is ended, the DMR  100 A 1  notifies the end of the reproduction to the DMC  200 . Therefore, the DMC  200  can obtain the reproducing state of the content in the DMR  100 A 1 . When the DMC  200  determines that the DMR  100 A 1  completes the reproduction (YES in S 106 ), the DMC  200  obtains an URL of the next content in the content list of the DMS  300  held by the DMC  200  (S 108 ), and executes the process in S 105 . When the DMC  200  determines that the DMR  100 A 1  is reproducing the content (NO in S 106 ), the reproducing state in the DMR  100 A 1  is displayed on the display section  200 E of the DMC  200  (S 107 ). The reproducing state in the DMR  100 A 1  includes a status such as reproducing, pause, or stop, the number of progress seconds of the on-reproducing content, and meta-information about the on-reproducing content. The status and the number of progress seconds are displayed on the display section  200 E based on information to be transmitted to the DMC  200  by the DMR  100 A 1 . After the DMC  200  executes the process in S 107 , the DMC  200  again executes the process in S 106 . 
         [0063]    The DMR  100 A 1  in the flowchart of  FIG. 5  receives the URL transmitted in S 105  in  FIG. 4  (S 201 ). The DMR  100 A 1  stores the URL received in S 201  (S 202 ). The URL received in S 201  is a URL of a content of the DMS  300  as destination to which the DMR  100 A 1  requests to distribute the content. 
         [0064]    The DMR  100 A 1  requests the DMS  300  to distribute the content using the URL received in S 201  (S 203 ). The DMR  100 A 1  reproduces the content data distributed from the DMS  300  (S 204 ). 
         [0065]    The DMR  100 A 1  determines whether the request for transmitting the content information of the content being reproduced by the DMR  100 A 1  is received from the DMP  100 A 2  (S 205 ). The content information includes a track name of the content or the like. When the DMR  100 A 1  determines that the request for the content information is not received from the DMP  100 A 2  (NO in S 205 ), the DMR  100 A 1  determines whether the reproduction of the on-reproducing content is completed (S 207 ). When the DMR  100 A 1  determines that the request for the content information is received from the DMP  100 A 2  (YES in S 205 ), the information about the on-reproducing content is transmitted to the DMP  100 A 2  (S 206 ). 
         [0066]    When the DMR  100 A 1  determines that the reproduction of the on-reproducing content is completed (YES in S 207 ), the DMR  100 A 1  notifies the completion of the content reproduction to the DMC  200  (S 208 ). When the DMR  100 A 1  determines that the reproduction of the on-reproducing content is not completed (NO in S 207 ), the DMR  100 A 1  transmits a reproduction status and progress information about the reproduction to the DMC  200  (S 209 ). 
         [0067]    The DMP  100 A 2  in the flowchart of  FIG. 6  receives an instruction for starting the reproduction of the content identical to the content being reproduced by the DMR  100 A 1  according to the user&#39;s operation (S 301 ). This instruction is carried out by the user operating the operating section  100 F of the DMP  100 A 2 . 
         [0068]    The DMP  100 A 2  requests the DMR  100 A 1  for information about the DMS  300  as destination to which the DMR  100 A 1  accepts the distribution of the content (S 302 ). Since the URL obtained by the process in S 302  is a URL for reproducing the content, it also includes information other than an IP Address of the DMS  300 . Therefore, the DMP  100 A 2  fetches the IP Address of the DMS  300  from the URL received from the DMR  100 A 1  (S 303 ). 
         [0069]    The DMP  100 A 2  requests the DMR  100 A 1  for information about the content being reproduced by the DMR  100 A 1  (S 304 ). 
         [0070]    The DMP  100 A 2  connects to the DMS  300  specified in S 303 , and requests for the “All Tracks” list (S 305 ). The “All Tracks” list is a list of tracks such as Track A 11  and Track A 12  in  FIG. 3 . In general, since the DMS  300  stores a plurality of contents, the list of the plurality of contents can be obtained in S 305 . 
         [0071]    The DMP  100 A 2  determines whether the content information obtained in S 304  matches with the content information about each of the contents in the content list obtained in S 305 . When the DMP  100 A 2  determines that they match (YES in S 306 ), the DMP  100 A 2  requests the DMS  300  for the content data of the content determined as matching, and starts the reproduction (S 307 ). When the DMP  100 A 2  determines that a content having the content information matching with the content information obtained in S 304  is not present in the content list obtained in S 305  (NO in S 306 ), the DMP  100 A 2  cannot specify the content that is identical to the content being reproduced by the DMR  100 A 1 , and thus ends the process. After the reproduction of the content that is started in S 307  is completed, the DMP  100 A 2  reproduces the next content according to the content list in  FIG. 3 . On the other hand, the DMR  100 A 1  reproduces the content according to the content list of the DMC  200 . That is, the DMR  100 A 1  and the DMP  100 A 2  continue the reproduction according to the different content lists. The DMR  100 A 1  and the DMP  100 A 2  reproduce the content from speakers (the DMP speaker  101  and the DMR speaker  102 ) arranged in different rooms. 
         [0072]    According to the first embodiment, when the DMP  100 A 2  receives the instruction for reproducing the content identical to that of the DMR  100 A 1 , the DMP  100 A 2  automatically searches the DMS  300  for the content having the content information matching with the content information about the content being reproduced by the DMR  100 A 1 , and starts the reproduction. 
         [0000]    [Second Embodiment in which the DMP Starts the Reproduction of the Content Identical to that of DMR] 
         [0073]      FIG. 7  is a flowchart illustrating the DMR  100 A 1 .  FIG. 8  is a flowchart illustrating the DMP  100 A 2 . The DMP  100 A 2  in the second embodiment uses content data instead of content information for determining whether a content is identical to the content being reproduced by the DMR  100 A 1 . In  FIG. 7 , the same processes as in  FIG. 5  are denoted by the same reference symbols, and descriptions thereof will be omitted. In  FIG. 8 , the same processes as in  FIG. 6  are denoted by the same reference symbols, and descriptions thereof will be omitted. 
         [0074]    The DMR  100 A 1  in the flowchart of  FIG. 7  receives a content instructed by the DMC  200  from the DMS  300 , and starts the reproduction (S 204 ). After the start of the reproduction, the DMR  100 A 1  stores the content data received from the DMS  300  for reproduction into the content data buffer  100 B 1  that is a temporary buffer (S 401 ). The content data stored in the content data buffer  100 B 1  may have a size for enabling the determination that the two contents are identical. An example of such data is data for first 10 seconds of contents. 
         [0075]    The DMR  100 A 1  determines whether the DMP  100 A 2  requests for obtaining content data (S 402 ). When the determination is made that content data is not requested (NO in S 402 ), the DMR  100 A 1  executes the process in S 207 . When the DMR  100 A 1  determines that the request for obtaining the content data is received (YES in S 402 ), the DMR  100 A 1  transmits the content data in the content data buffer  100 B 1  to the DMP  100 A 2  (S 403 ). 
         [0076]    When the reproduction of the on-reproducing content is completed, the DMR  100 A 1  clears the content data buffer  100 B 1  (S 404 ). 
         [0077]    The DMP  100 A 2  in the flowchart of  FIG. 8  obtains an IP Address of the DMS  300  according to the process in S 303 , and requests the DMR  100 A 1  to transmit the content data in the content data buffer  100 B 1  (S 501 ). 
         [0078]    The DMP  100 A 2  obtains the “All Tracks” list from the DMS  300  (S 305 ), and requests the DMS  300  for content data of first 10 seconds of the respective contents included in the “All Tracks” list to obtain the content data (S 502 ). The DMP  100 A 2  determines whether the content data obtained in S 501  matches with the content data obtained in S 502  (S 503 ). 
         [0079]    When the DMP  100 A 2  determines that the content data obtained in S 501  matches with the content data obtained in S 502  (YES in S 503 ), the DMP  100 A 2  requests the DMS  300  for the matched content data of the content, and starts the reproduction (S 307 ). When the DMP  100 A 2  determines that the content data obtained in S 501  does not match with the content data obtained in S 502  (NO in S 503 ), the DMP  100 A 2  determines whether the processes in S 502  and S 503  are executed on all the contents in the content list obtained in S 305  (S 504 ). When the determination is made that not all the contents are checked (NO in S 504 ), the next content in the “All Track” list is subject to the check (S 505 ). When the DMP  100 A 2  determines that all the contents are checked (YES in S 504 ), the DMP  100 A 2  determines that the content identical to the content being reproduced by the DMR  100 A 1  cannot be obtained, and ends the process (YES in S 504 ). 
         [0080]    According to the second embodiment, when the DMP  100 A 2  searches for the content identical to the content being reproduced by the DMR  100 A 1 , the DMP  100 A 2  utilizes the content data so as to be capable of reliably determining whether the contents are identical to each other. 
         [0000]    [Third Embodiment in which DMP Starts Reproduction of Content Identical to that of DMR] 
         [0081]      FIG. 9  illustrates a state where a plurality of contents whose content information is identical to each other is registered in “All Tracks” managed by the DMS  300 . That is, Track All and Track A 15  are different contents, but have identical content information (meta-information). In this case, the DMP  100 A 2  cannot specify only one content that is identical to the content being reproduced by the DMR  100 A 1  based on the content information. According to the second embodiment, content being reproduced by the DMR  100 A 1  can be specified uniquely, but since the DMP  100 A 2  obtains content data from the DMS  300  and compare the content data one by one (S 502  and S 503 ), the process takes a long time. 
         [0082]      FIG. 10  is a flowchart illustrating the DMR  100 A 1  according to the third embodiment.  FIG. 11  is a flowchart illustrating the DMP  100 A 2  according to the third embodiment. The DMP  100 A 2  in the third embodiment first uses content information for determining whether a content is identical to the content being reproduced by the DMR  100 A 1 . The DMP  100 A 2  then determines, as to the contents whose content information is determined as matching with each other, whether their content data match with each other. In  FIG. 10 , the same processes as in  FIG. 7  are denoted by the same reference symbols and descriptions thereof will be omitted. In  FIG. 11 , the same processes as in  FIG. 8  are denoted by the same reference symbols and descriptions thereof will be omitted. 
         [0083]    In the flowchart of  FIG. 10 , the DMR  100 A 1  starts the reproduction (S 204 ), and stores data about the content started to be reproduced into the content data buffer  100 B 1  (S 401 ). When the DMR  100 A 1  determines that a request for receiving the content information being reproduced by the DMR  100 A 1  is received from the DMP  100 A 2  (YES in S 601 ), the on-reproducing content information is transmitted to the DMP  100 A 2  (S 602 ), and when the determination is made that the request is not received (NO in S 601 ), the process goes to S 603 . 
         [0084]    When DMR  100 A 1  determines that the request for transmitting the content data is received from the DMP  100 A 2  (YES in S 603 ), the content data of the content data buffer  100 B 1  is transmitted to the DMP  100 A 2  (S 604 ), and when the determination is made that the request is not received (NO in S 603 ), the process goes to S 207 . 
         [0085]    In the flowchart of  FIG. 11 , the DMP  100 A 2  requests the DMR  100 A 1  for the content information about the content being reproduced by the DMR  100 A 1  and obtains the content information (S 304 ). Further, the DMP  100 A 2  obtains the content data from the DMR  100 A 1  (S 501 ). The DMP  100 A 2  then obtains the “All Tracks” list from the DMS  300  (S 305 ). 
         [0086]    The DMP  100 A 2  determines whether the content information about the content obtained in S 305  matches with the content information obtained in S 304  (S 701 ). When they match with each other (YES in S 701 ), the DMP  100 A 2  registers a matched content ID into an arrangement trackList [ ]. For example, the content ID of Track A 13  is “1.3”. The first part “1” is a number indicating an “AllTracks” folder, and “.” indicates the hierarchical level. The last part “3” indicates a serial number of Track A 13  in the “All Tracks” folder. 
         [0087]    The DMP  100 A 2  determines whether the process in S 701  is executed on all the contents obtained in S 305  (S 504 ), and when the determination is made that all the contents are checked (YES in S 504 ), the DMP  100 A 2  requests the DMS  300  for the content data of the contents registered in the arrangement trackList [ ] (S 703 ). The DMP  100 A 2  determines whether the respective contents registered in the arrangement trackList [ ] have content data matching with the content data obtained in the process in S 501  (S 704 ). When determined as not matching (NO in S 704 ), the DMP  100 A 2  executes the process after S 703  on the next content registered in the arrangement trackList [ ], and when determined as matching (YES in S 704 ), the DMP  100 A 2  starts to reproduce the matched content (S 307 ). The processes in S 703  and in S 704  may be executed only when two or more contents are registered in the arrangement trackList [ ]. 
         [0088]    According to the third embodiment, when the DMP  100 A 2  searches for a content identical to the content being reproduced by the DMR  100 A 1 , the DMP  100 A 2  first specifies a content whose content information matches, and further specifies a content whose content data match. For this reason, even when a plurality of contents whose content information match are present, the DMP  100 A 2  can uniquely specify the content being reproduced by the DMR  100 A 1 . 
         [0089]      FIG. 12  illustrates another embodiment in which the DMS  300  manages contents.  FIG. 12  illustrates a form where contents are managed for respective artists. An All Artists folder exists below the highest hierarchical level “musicRoot”. A list of artist folders for storing contents to be stored in the DMS  300  for respective artists exists on a lower hierarchical level below All Artists. An artist name is generally added to the artist folder. Further, a plurality of album folders exist in a lower hierarchical level below the artist folders, respectively. Further, contents (tracks) exist in a lower hierarchical level below the album folder. 
         [0000]    [Fourth Embodiment in which DMP Starts Reproduction of Content Identical to that of DMR] 
         [0090]      FIG. 13  ( FIG. 13A  and  FIG. 13B ) is a flowchart illustrating the DMP  100 A 2  according to the fourth embodiment. When a content identical to the content being reproduced by the DMR  100 A 1  is instructed to be reproduced, the DMP  100 A 2  in the fourth embodiment specifies an artist hierarchy and an album hierarchy to which the specified content belongs, and automatically moves between the hierarchical levels so as to reproduce the content. For this reason, the user can easily obtain the album and the artist of the content in the DMP  100 A 2 . 
         [0091]    The DMP  100 A 2  executes the processes in S 301  to S 303  described in  FIG. 6 . The DMP  100 A 2  requests the DMR  100 A 1  for information about the content being reproduced by the DMR  100 A 1  (S 801 ). The DMP  100 A 2  requests for artist information, album information, and track information about the content being reproduced by the DMR  100 A 1 . 
         [0092]    The DMP  100 A 2  determines whether the artist information is included in information obtained from the DMR  100 A 1  in S 801  (S 802 ). When the determination is made that the artist information is not included (NO in S 802 ), the process is ended, and when the determination is made that the artist information is included (YES in S 802 ), the DMP  100 A 2  requests the DMS  300  for the artist list (S 803 ). That is, the DMP  100 A 2  obtains the artist list below All Artists in  FIG. 12 . 
         [0093]    The DMP  100 A 2  compares the artist information obtained in S 801  with each artist name in the artist list obtained in S 803  (S 804 ). When the determination is made that the artist names match (YES in S 804 ), the DMP  100 A 2  stores a content ID in a variable “path”. When the determination is made that the artist names do not match (NO in S 804 ), the DMP  100 A 2  determines whether the process in S 804  is executed on all the artists obtained in S 803  (S 805 ). When the determination is made that all the artists are checked (YES in S 805 ), the process is ended, and when the determination is made that not all the artists are checked (NO in S 805 ), the DMP  100 A 2  executes the process after S 804  on the next artist in the artist list. The value set to “path” by the process in S 807  is “1.2”, for example, when the matched artist is Artist B in  FIG. 12 . 
         [0094]    The DMP  100 A 2  determines whether the content information obtained by the process in S 801  includes album information (S 808 ). When the determination is made that the album information is not included (NO in S 808 ), the DMP  100 A 2  ends the process, and when the determination is made that the album information is included (YES in S 808 ), the DMP  100 A 2  obtains from the DMS  300  an album list in a lower hierarchical level below the artist specified by the process in S 804  (S 809 ). For example, when Artist B is specified by the process in S 804 , the DMP  100 A 2  obtains an album list below Artist B. 
         [0095]    Similarly to the process on the artist name, the DMP  100 A 2  determines whether a folder having the album name identical to the album name obtained in S 801  is present in the album list obtained in S 809  (S 810 ), and when the determination is made that the album name is identical (YES in S 810 ), the DMP  100 A 2  adds a content ID of the matched album folder to the variable “path” (S 813 ). When the determination is made that the album name is not identical (NO in S 810 ), the DMP  100 A 2  determines whether the process in S 810  is executed on all the album folders obtained in S 809  (S 811 ). When the determination is made that all the album folders are checked (YES in S 811 ), the DMP  100 A 2  ends the process, and when the determination is made that not all the album folders are checked (NO in S 811 ), the DMP  100 A 2  targets for the next album folder (S 812 ). For example, when Album B 1  is specified in S 810  in  FIG. 12 , “path” is set to “1.2.1” by the process in S 813 . 
         [0096]    The DMP  100 A 2  determines whether the content information obtained by the process in S 801  includes track information (S 814 ). When the determination is made that the track information is not included (NO in S 814 ), the process is ended, and when the determination is made that the track information is included (YES in S 814 ), the DMP  100 A 2  obtains from the DMS  300  a track list in a lower hierarchical level below the album specified by the process in S 810  (S 815 ). 
         [0097]    The DMP  100 A 2  determines whether a content having the track name identical to the track name obtained in S 801  is present in the track list obtained in S 815  (S 816 ), and when the determination is made that the track names match, (YES in S 816 ), the DMP  100 A 2  adds a content ID to the variable “path” (S 819 ). When the determination is made that the track names do not match (NO in S 816 ), the DMP  100 A 2  determines whether the process in S 816  is executed on all the tracks obtained in S 815  (S 817 ). When the determination is made that all the tracks are checked (YES in S 817 ), the process is ended, and when the determination is made that not all the tracks are checked (NO in S 817 ), the DMP  100 A 2  targets for the next track (S 818 ). For example, when Track B 11  in  FIG. 12  is specified in S 816 , the “path” is set to “1.2.1.1” by the process in S 819 . 
         [0098]    The DMP  100 A 2  automatically moves between the hierarchical levels ( FIG. 12 ) of the content folder in the DMS  300  based on the ID set to the “path”, and starts to reproduce the content (S 820 ). When the value of the “path” is “1.2.1.1”, the DMP  100 A 2  accesses to All Artists, Artist B, Album A 1 , and Track B 11  in  FIG. 12  in this order. 
         [0099]    According to the fourth embodiment, when the DMR  100 A 1  is instructed to reproduce a content identical to the on-reproducing content, the DMP  100 A 2  automatically specifies the artist hierarchy and the album hierarchy to which the instructed content belongs, and automatically moves between the hierarchical levels of the DMS  300  so as to reproduce the content. Therefore, the user can easily obtain another album or the like of the artist to which the content being reproduced by the DMR  100 A 1  belongs. The fourth embodiment illustrates an example using an artist name and an album name, but another tag information such as a genre name and a date on which a content is released may also be used. For example, when a genre name is used, the DMP  100 A 2  automatically moves to a folder of a genre identical to the genre to which the content being reproduced by the DMR  100 A 1  belongs so as to reproduce the content. 
         [0000]    [Fifth Embodiment in which DMP Starts to Reproduce Content Identical to that of DMR] 
         [0100]      FIG. 14  is a flowchart illustrating the DMP  100 A 2  according to the fifth embodiment. Even when the DMP  100 A 2  in the fifth embodiment cannot obtain track information from the DMR  100 A 1 , the DMP  100 A 2  specifies a content being reproduced by the DMR  100 A 1  as well as information about a folder including the content. In  FIG. 14 , the same processes as in  FIG. 13  are denoted by the same reference symbols, and descriptions thereof will be omitted. 
         [0101]    The DMP  100 A 2  executes the process in S 301  to S 303 , and further executes the process in S 801  to S 813 . The DMP  100 A 2  determines whether track information in content information obtained by the process in S 801  is normally set (S 814 ). 
         [0102]    When the determination is made that the track information is not obtained (NO in S 814 ), the DMP  100 A 2  requests the DMR  100 A 1  for content data about the on-reproducing content (S 901 ). The DMP  100 A 2  then requests the DMS  300  for a content list below the folder specified by the value currently set to the variable “path” (S 902 ). Since the value that can specify an album is set to the “path” by the processes in S 807  and S 813 , the DMP  100 A 2  can specify the album folder based on the “path”. For example, when the “path” is set to “1.2.1”, the DMP  100 A 2  obtains a track list in a lower hierarchical level below Album B 1  in  FIG. 12 . 
         [0103]    The DMP  100 A 2  obtains content data of contents in the track list obtained in S 902  from the DMS  300  (S 903 ), and determines whether a content having content data matching with the content data obtained in S 901  is present (S 904 ). When the determination is made that the matched content is present (YES in S 904 ), the process in S 820  is executed, and when the determination is made that the matched content is not present (NO in S 904 ), the process is ended. 
         [0104]    According to the fifth embodiment, even when a part of information obtained from the DMR 100 A 2  in S 801  is missing, the DMP  100 A 2  can specify a content being reproduced by the DMR  100 A 1 . Even when not only track information but also album information is missing in S 801 , the DMP  100 A 2  executes the process in S 902  to S 904  on all tracks below the artist folder, so as to be capable of specifying a content as well as hierarchical information. 
         [0105]    The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. The content data may be video data or still image data. Further, after the DMP  100 A 2  specifies a content identical to that of the DMR  100 A 1 , the DMR  100 A 1  and the DMP  100 A 2  reproduce the contents according to the different content lists. However, the DMP  100 A 2  may reproduce the content identical to the content being reproduced by the DMR  100 A 1 . In this case, every time when the DMP  100 A 2  completes reproduction of one content, the process in  FIG. 6  or  FIG. 8  is executed.