JP2009128464A - Portable media player, file server, media file transfer method, and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a portable media player reducing the time required for data acquisition at reproduction start. <P>SOLUTION: The portable media player 20 acquires a partial file of the media file from a server transferring the media file before receiving a media file, starts reproduction of the previously acquired partial file when receiving reproduction request of the media file, and reproduces the media file including the partial file acquired from the server. In addition, path information to the location of the partial file in its own player and path information to the location of the media file including the partial file in a network can be held in association with each other. A file server 10 generates the partial file by selecting a part of the media file, and transfers a generated partial file to the portable media player 20. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a portable media player (hereinafter referred to as a PMP (Portable Media Player)) having a streaming reproduction function in a network environment, a file server for transferring a media file to the PMP, a file transfer method using these, and a computer. Regarding the program.

  There is a PMP type client having a streaming reproduction function in a network environment (see, for example, Patent Document 1). This is a network (LAN: Local Area Network) connection between the file server and the PMP, and media files such as music files, moving image files or still image files stored on the file server side are streamed to the PMP side, Playback is performed on the PMP side.

  As an advantage, there is no need for a built-in medium for storing files on the PMP side. In general, there are media files of several MB to several GB units, and the built-in media for storing them must have a large capacity of several GB.

  FIG. 1 shows a conventional system configuration, and FIG. 2 shows a procedure from when a PMP acquires a file from a file server via a network to start playback. As shown in FIG. 1, for example, the file server 100 and the fixed player 300 are connected by a wired LAN, and the file server 100 and the PMP 200 are connected by a wireless LAN. In the case of a wireless LAN, it can be connected via a hot spot installed outdoors.

  As shown in FIG. 2, the PMP 200 accesses the file server 100 by specifying a shared folder (S1). As a result, a communication start request and response are made between the PMP 200 and the file server 100 (S2), and negotiations for exchanging parameters necessary for subsequent communication are performed (S3), and authentication is performed. A session is established (S4), and the PMP 200 acquires index information of files and folders from the file server 100 (S5).

  Subsequently, the PMP 200 displays the acquired media file in the shared folder on a UI (User Interface) such as a display unit (S6). The user refers to the displayed media file, selects a media file from the displayed media file, and requests playback (S7). When a reproduction request is made, the PMP 200 acquires a certain amount of file information from the file server 100 (S8).

  The PMP 200 that has acquired the file information analyzes the legitimacy of the acquired file (S9), and starts reproduction (S10). Thereafter, the file information is acquired sequentially (S11).

  Here, the analysis of the validity of the file is, for example, analyzing whether or not the file is a valid file format defined in the standard. For example, in the case of MP3 (MPEG Audio Layer-3), it is analyzed whether the frame header is valid. Alternatively, it is analyzed whether or not the music file has a sampling rate, bit rate, and number of channels within a range that the player can play.

JP 2007-66473 A

  On the PMP side, when streaming playback is started, it is necessary to acquire the presence of a file in the server, and thereafter, it is necessary to acquire a certain amount of file information.

  Therefore, it takes time to acquire the existence of a file and to acquire a certain amount of file information after instructing the file to be played, and to spend time to play the desired file in total. Become.

  For example, a wired LAN in a home is a closed environment, and a transfer rate for each environment is promised to some extent. However, particularly in a wireless LAN environment using an outdoor hot spot, the network transfer rate depends on the environment or the degree of congestion. Depending on the situation, the time required for network authentication and data acquisition may be longer. As a result, the playback start may be further delayed, which is disadvantageous to the user.

  The present invention has been made to solve such a problem, and is a PMP, a file server, a media file transfer method, and a computer program that can reduce the time required to acquire file information at the start of reproduction. The purpose is to provide.

  In order to achieve the above object, the present invention is a PMP that receives and plays back a media file to be streamed, and prior to receiving the media file, the partial file of the media file is transferred from the source of the media file. A partial file acquisition unit to acquire, and a media file playback unit to start playback of a partial file acquired in advance upon receiving a media file playback request, and to acquire and play a media file including the partial file from a transfer source; Is provided.

  Further, it is possible to provide partial file holding means for holding the path information to the storage location of the partial file in the player and the path information to the storage location of the media file including the partial file in the network in association with each other.

  Also, the media file playback means starts playback of the media file that follows the partial file after the playback of the partial file, for example. Alternatively, even when a partial file is being played, it is possible to switch from playing a partial file to playing a media file following the partial file when a certain amount of media files following the partial file are acquired.

  The partial file holding means can create a tree-structured index including the acquired partial file in the lowest node according to a predetermined rule.

  Another aspect of the present invention is a file server, comprising: a partial file generation unit that selects a part of a media file and generates a partial file; and a partial file transfer unit that transfers the generated partial file to the PMP of the present invention. Prepare.

  Another aspect of the present invention is a media file transfer method for receiving a media file to be transferred by streaming and playing it by PMP. The PMP receives the media file from the transfer source of the media file prior to receiving the media file. When the partial file is acquired and a reproduction request for the media file is received, reproduction of the partial file acquired in advance is started, and a media file including the partial file is acquired from the transfer source and reproduced.

  Further, the PMP can hold the path information to the storage location of the partial file in the player and the path information to the storage location of the media file including the partial file in the network in association with each other.

  It is also possible to start playback of the media file that follows the partial file after the playback of the partial file, or to acquire a certain amount of media files that follow the partial file even during playback of the partial file. It is also possible to switch from playback of a partial file to playback of a media file that follows the partial file at that time.

  In addition, a tree-structured index including the acquired partial file at the lowest node can be created according to a predetermined rule.

  Further, the file server can select a part of the media file to generate a partial file, and transfer the generated partial file to the PMP.

  Another aspect of the present invention is a computer program that, when installed in a general-purpose computer apparatus, causes the general-purpose computer apparatus to realize functions corresponding to at least some of the functions of the PMP or file server of the present invention. It is a computer program.

  By recording the computer program of the present invention on a recording medium, a general-purpose computer apparatus can install the computer program of the present invention using this recording medium. Alternatively, the computer program of the present invention can be directly installed on a general-purpose computer device via a network from a server holding the computer program of the present invention.

  Thereby, a function corresponding to the function of the PMP or the file server of the present invention can be realized using a general-purpose computer device.

  The computer program of the present invention includes not only a program that can be directly executed by a general-purpose computer device but also a program that can be executed by being installed on a hard disk or the like. Also included are those that are compressed or encrypted.

  According to the present invention, the time required to acquire file information at the start of playback can be shortened.

  A configuration of a portable media player (hereinafter referred to as PMP) and a file server according to an embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a block diagram of the PMP of this embodiment, and FIG. 4 is a block diagram of the file server of this embodiment.

  As shown in FIG. 3, the PMP 20 of the present embodiment is a partial file acquisition unit that acquires a partial file of a media file from the file server 10 that is the transfer source of the media file before receiving the media file. When the file acquisition unit 21 receives a reproduction request for a media file, the reproduction of the partial file acquired in advance is started, and a media file including the partial file is acquired from the file server 10 and reproduced. And a media file playback unit 23.

  The acquired partial file is held in the partial file holding unit 22 and used by the media file playback unit 23.

  In addition, the media file playback unit 23 displays information stored in the partial file holding unit 22 on the display unit 24. The user refers to this display, selects a media file desired to be played, and inputs a playback request to the media file playback unit 23 through the operation unit 25.

  Further, as shown in FIG. 4, the file server 10 of the present embodiment selects a part of the media file and generates a partial file, and a partial file transfer that transfers the generated partial file to the PMP 20. And a partial file transfer unit 15 as means.

  The partial file generated by the partial file generation unit 13 is stored in the partial file holding unit 14 and delivered to the PMP 20 by the partial file transfer unit 15.

  A media file distributed by the media file transfer unit 11 serving as a media file transfer unit is held in the media file holding unit 12. A partial file generation unit 13 as a partial file generation unit generates a partial file from the media file held in the media file holding unit 12.

Next, a preparation stage until the PMP 20 of the present embodiment performs reproduction of a media file will be described with reference to FIGS. FIG. 5 shows a folder tree that the file server 10 has. FIG. 6 is a diagram showing a folder tree that the PMP 20 has. FIG. 7 is a diagram showing a virtual folder tree that the PMP 20 has. FIG. 8 is a flowchart showing a tree list transfer procedure from the file server 10 to the PMP 20.
(1) The PMP 20 and the file server 10 are connected by a wired cable (wired LAN, wired USB (Universal Serial Bus), etc.).
(2) Shared folder of the file server 10 The folder tree configuration information shown in FIG. 5 below and the partial file picked up from the top of the media file are transferred to the media (flash memory, HDD (Hard Disk Drive), etc.) built in the PMP 20 To do.
(3) Create a tree-structured index as shown in FIG. Further, as shown in FIG. 7, the path information of the partial file in the PMP and the path information of the network on the server side are associated with each media file node (the folder tree in FIG. 7 is called a virtual folder tree). ).
(4) Release the connection between the PMP 20 and the file server 10.

  Here, the procedure for transferring a partial file from the file server 10 to the PMP 20 will be described in detail with reference to the flowchart of FIG.

  When the transfer of the shared folder is instructed on the PC application in the file server 10 (S10), “Transferring” is displayed on the PC application (S11), and the folder structure and file structure below the PC shared folder are displayed in a tree. The list is stored (S12), and the tree list is transferred to the PMP side (S13).

  When the tree list is transferred to the PMP side, a file not transferred to the PMP is searched under the shared folder (S14). If there is an untransferred file, the file to be transferred is opened (S15). ). At this time, the meta information is acquired from the header information of the file and stored in the memory (S16).

  Up to N seconds at the beginning of the file are decoded into PCM data and temporarily saved (S17). The PCM data is converted into a predetermined file format (S18). The meta information stored in advance is written in the header of the converted file (S19). The converted file is transferred to the PMP side (S20). The converted file is associated with the tree list transferred to the PMP side (S21).

  When there is no untransferred file in this way (S14), the transfer end display is performed (S22).

  Next, the playback procedure in the PMP 20 will be described with reference to FIG. FIG. 9 is a flowchart showing a playback procedure in the PMP 20. When the PMP 20 is taken outdoors and played under a wireless network connection environment, the procedure is as shown in FIG.

  That is, the media file in the shared folder of the file server 10 is displayed on the display unit 24 using the virtual folder information transferred in advance (S30). The user selects a desired media file from the media files displayed on the display unit 24 and makes a playback request through the operation unit 25 (S31).

  The file information is acquired with the partial file transferred in advance and the validity of the file is analyzed (S32). Further, the partial file transferred in advance is reproduced (S33).

  Subsequently, the file server 10, the shared folder, and the media file are designated and accessed (S34). Thereby, between the PMP 20 and the file server 10, a request to start communication and a response are made (S35), and negotiations for exchanging parameters necessary for subsequent communication are performed (S36), and authentication is performed. A session is established (S37), and the PMP 20 acquires file and folder index information from the file server 10 (S38).

  Further, when a certain amount of file information is acquired (S39). The legitimacy of the acquired file is analyzed (S40), and reproduction is continued (S41). Thereafter, the file information is acquired sequentially (S42).

  If the validity of the file is not recognized in step S40, it is found that the partial file acquired in the past is different from the file information acquired this time. In such a case, the PMP 20 asks the file server 10 to It is possible to take measures such as notifying that the file information transferred in error is in error and prompting retransmission of the correct file information.

  Compared with FIG. 2, since there is a file as a playback candidate and a certain amount of file information of the file to be played back is already stored in the built-in medium of the PMP 20, a network connection is not necessary in the procedure up to the start of playback. Yes, file playback can be started immediately.

  Next, a method for generating a partial file will be described with reference to FIGS. FIG. 10 is a diagram for explaining a partial file generation method in a WAV (RIFF Waveform Audio Format) file, and FIG. 11 is a diagram for explaining a partial file generation method in an MP3 file.

  For example, a WAV file can be created by cutting the file at an arbitrary data frame in the data chunk and changing the data size, as shown in FIG. Alternatively, an MP3 file can be created by cutting the file at the start position of arbitrary sync data, as shown in FIG. Partial file # 1 is for one data frame, and partial file # 2 is for two data frames. In addition, file conversion is performed during transfer as necessary.

  Next, a procedure for switching between the partial data reproduction based on the file information acquired from the partial file and the data reproduction based on the file information acquired from the network is necessary. The switching procedure will be described with reference to FIGS.

  When playing back, the file information actually used is either the saved partial file information or the file information acquired from the network, and the file information acquired from the network from the partial file playback by the partial file as playback progresses It is necessary to switch to all file playback.

  In the example of FIG. 12, partial file reproduction is first performed (S50), and when partial file reproduction is completed (S51), switching to full file reproduction based on file information acquired from the network is performed (S52).

  In the example of FIG. 13, when a partial file is first played back (S60) and a certain amount of file information is obtained from the network (amount of file information is not exhausted during playback processing) (S61), all the file information obtained from the network is obtained. Switching to file playback (S62).

  In both examples of FIGS. 12 and 13, when switching from partial file playback to full file playback, it is possible to seamlessly switch to playback of all files from a portion subsequent to a portion already played back in the partial file.

  The switching process will be described in more detail. For example, music data of an audio file is composed of a set of frames (packets) that are cut into pieces. Here, taking MP3 as an example, it is composed of a set of frames (packets) that are cut into pieces every 1152 samples (about 26 ms if the sample rate is 44.1 kHz).

  Therefore, when the partial file is created, if it is divided at this frame break, if the partial file is decoded N frames from the beginning at the time of playback, it will be decoded from the (N + 1) th frame when switching to playback of the subsequent file. By switching, it is possible to seamlessly switch to all file playback.

  For example, in the process of FIG. 12, the partial file is determined in advance to the Nth frame, and when the partial file is decoded by N frames, the reproduction of the subsequent file is started from the (N + 1) th frame. In the example of FIG. 13, when acquiring a certain amount of file information that does not run out of file information during the playback process, it acquires up to any frame break, and the subsequent file is played back by the frame following that break. Start decoding.

  In addition, since the acquisition of the file information from the network is not stopped even when the reproduction is paused, if a certain amount of file information can be acquired when the reproduction is resumed, the file information acquired from the network is switched to the reproduction.

  Further, when the partial file has been played back quickly, such as by fast-forwarding, playback is not resumed until the acquisition of file information from a certain amount of network is finished.

  Also, when playback from a time zone outside the partial file is prompted, such as during resume playback, playback is resumed after file information is acquired from the network.

  Needless to say, if there is no free space in the PMP built-in media, the partial file will not be transferred. In this case, however, after a certain amount of file information has been acquired from the network when a playback instruction for the file is given, Let's play it.

  The network path information storage destination may be stored in association with the file in the database, or may be embedded in a URL (Universal Resource Locator) information frame or a private frame in the metadata of the media file. As an example, a user-defined URL link frame (WXXX) can be added to the ID3v2.3 tag specification of MP3.

  Next, the consistency check procedure of the shared folder will be described with reference to FIG. FIG. 14 is a flowchart showing the procedure of shared folder consistency check in the PMP 20. After the data on the file server 10 side is transferred to the PMP 20 and the file transfer to the PMP 20 is performed again after the file on the file server 10 side is deleted, the partial file corresponding to the file that no longer exists is deleted. It is also deleted from the virtual file tree.

  That is, when the shared folder consistency check is instructed on the PC application of the file server 10 (S70), the PMP 20 opens the stored virtual folder tree (S71), and the file on the file server 10 side corresponding to the virtual file is opened. Is searched (S73). At this time, if the file on the file server 10 side corresponding to the virtual file does not exist, the partial file on the PMP 20 side corresponding to the virtual file is deleted (S74). Further, the virtual file corresponding to the file is deleted from the virtual folder tree (S75). This procedure is repeated until there are no unchecked virtual files in the virtual folder tree (S72).

  In addition, when the data on the file server 10 side is transferred to the PMP 20, the file on the file server 10 side is modified, and then the file transfer to the PMP 20 is performed again, the file corresponding to the modified file Will be modified.

  In addition, after the start of reproduction, if the file does not exist when connected to the network, it is possible to reproduce until the end of the partial file. As a method for detecting whether or not the file is concerned, a method such as setting the sum value of a certain amount of data of the original file can be considered.

  Next, another embodiment of a method for creating a virtual folder tree will be described with reference to FIGS. At the time of file transfer from the file server 10 to the PMP 20, in addition to creating the virtual folder tree described above, a user interface composed of an artist hierarchy and an album hierarchy as shown in FIG. 16 from the metadata of the file shown in FIG. It can also be provided.

  In this case as well, by relating the path information of the partial file in the PMP and the network path information of the file on the server side to the file node in the virtual folder tree, it is possible to reproduce without waiting time similarly.

  The PMP 20 may be a car audio with built-in media or the like other than a format that the user can wear and carry. In that case, a method of connecting to a home server PC in a stable wireless LAN environment can be considered in the garage.

(Explanation of effect)
When starting playback on the PMP side, there is no user interface waiting time for list display at the time of file selection, and there is no waiting time for file information acquisition at the start of playback. Can start.

  In addition, the size of the built-in media can be reduced compared to a non-network compatible PMP, leading to cost reduction.

  In addition, since the amount of transferred file data is smaller than that of a PMP that does not support the network, the time for transferring data from the file server to the PMP can be shortened.

  In addition, even when played off-line, it can be played once. For example, the present invention can be applied to a business model in which a part of a file is stored as a preset and access to the file server is permitted under a membership system so that all files can be reproduced.

(Example of computer program)
An embodiment of a computer program for realizing functions corresponding to at least a part of the functions of the file server 10 or the PMP 20 of the present embodiment by installing in a general-purpose computer apparatus will be described.

  For example, the media file transfer unit 11, the media file holding unit 12, the partial file generation unit 13, the partial file holding unit 14, the partial file transfer unit 15 in the file server 10, the partial file acquisition unit 21 in the PMP 20, the partial file holding unit 22, Functions corresponding to the functions of the media file playback unit 23 can be realized by installing the computer program of this embodiment in a general-purpose computer device (including an MPU (Micro Processor Unit) and the like).

  By recording the computer program of this embodiment on a recording medium, a general-purpose computer apparatus can install the computer program of this embodiment using this recording medium. Alternatively, the computer program of this embodiment can also be installed directly from a server that holds the computer program of this embodiment to a general-purpose computer device via a network.

  Thereby, the function corresponding to the function of at least one part of the file server 10 or PMP20 of a present Example is realizable using a general purpose computer apparatus.

  Note that the computer program of this embodiment includes not only a computer program that can be directly executed by a general-purpose computer device but also a computer program that can be executed by being installed on a hard disk or the like. Also included are those that are compressed or encrypted.

It is a conventional system configuration diagram. It is a flowchart which shows the procedure until the conventional PMP acquires a file from a file server via a network, and reproduction | regeneration starts. It is a block block diagram of PMP of this embodiment. It is a block block diagram of the file server of this embodiment. It is a figure which shows the folder tree which a file server has. It is a figure which shows the folder tree which PMP has. It is a figure which shows the virtual folder tree which PMP has. It is a flowchart which shows the tree list transfer procedure from a file server to PMP. It is a flowchart which shows the reproduction | regeneration procedure in PMP. It is a figure for demonstrating the partial file production | generation method in a WAV file. It is a figure for demonstrating the partial file production | generation method in MP3 file. It is a flowchart (switching after completion | finish of partial file reproduction | regeneration) which shows a data switching procedure. It is a flowchart (switching after acquisition of a fixed amount) which shows a data switching procedure. It is a flowchart which shows the procedure of the consistency check of the shared folder in PMP. It is a figure which shows the metadata of a partial file. It is a figure which shows the virtual folder tree comprised by the artist hierarchy and the album hierarchy.

Explanation of symbols

10, 100 File server 11 Media file transfer unit (media file transfer means)
12 Media file holding unit 13 Partial file generation unit (partial file generation means)
14 Partial file holding unit 15 Partial file transfer unit (partial file transfer means)
20, 200 PMP
21 Partial file acquisition unit (partial file acquisition means)
22 Partial file holding unit 23 Media file playback unit (media file playback means)
24 display unit 25 operation unit 300 fixed player

Claims (8)

In a portable media player that receives and plays streaming media files,
Prior to receiving the media file, a partial file acquisition means for acquiring a partial file of the media file from the transfer source of the media file;
Media file playback means for starting playback of the partial file acquired in advance upon receipt of a media file playback request, and acquiring and playing back the media file including the partial file from the transfer source;
A portable media player comprising:   2. A partial file holding means for holding the path information to the storage location of the partial file in the player and the path information to the storage location of the media file including the partial file in the network in association with each other. The portable media player as described.   The portable media player according to claim 1, wherein the media file playback means starts playback of a media file following the partial file after the playback of the partial file.   The media file playback means switches from playback of the partial file to playback of the media file following the partial file when a certain amount of media files following the partial file are acquired even during playback of the partial file. The portable media player according to claim 1.   3. The portable media player according to claim 2, wherein the partial file holding unit creates a tree-structured index including the acquired partial file in the lowest node according to a predetermined rule. Partial file generation means for selecting a part of a media file and generating a partial file;
A partial file transfer means for transferring the generated partial file to the portable media player according to claim 1;
A file server with In a media file transfer method for receiving a media file to be streamed and playing it on a portable media player,
Prior to receiving the media file, the portable media player acquires a partial file of the media file from the transfer source of the media file, and upon receiving a playback request for the media file, starts playing the previously acquired partial file. A media file transfer method characterized in that a media file including the partial file is acquired from the transfer source and played back.   A computer program that, when installed on a general-purpose computer device, causes the general-purpose computer device to realize functions corresponding to at least some of the functions of the portable media player according to any one of claims 1 to 5.

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