JP4124204B2 - Content playback device - Google Patents

Description

  The present invention relates to a content playback apparatus that plays back content recorded on a recording medium.

  In recent years, content such as video has been recorded not only on a tape but also on a randomly accessible recording medium such as an optical disk, a hard disk, or a semiconductor memory. Their recording capacity tends to increase year by year, and a large amount of content can be recorded on one recording medium. Therefore, technology for managing and reproducing such a large amount of content is becoming important.

  A video data management apparatus for playing back content, which is a conventional technique, will be described below.

FIG. 9 is a block diagram of a conventional video data management apparatus. When the input / output timing control unit 902 receives a video data distribution request from the CPU 901 under the video data file name, the input / output timing control unit 902 receives the header size of the video data related to the file name from the header table management unit 903 and the accumulated data management unit 904. The size of the entire video data is taken out, collected in the buffering means 905 and distributed from the data distribution means 906 to calculate and control a series of distribution schedule times. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 9-247645

  However, when there is no header table management means like the conventional video data management apparatus, and information necessary for content reproduction is recorded as a separate file for each content, all content to be reproduced is recorded. Since the file must be read, it takes time to start reproduction when the number of contents is large.

  In view of such a problem, an object of the present invention is to immediately start reproduction and continuously reproduce information when information necessary for content reproduction is recorded as a separate file for each content. And

  In order to solve the above problems, the present invention starts content playback after the total time length of content for which information necessary for playback exceeds the length that guarantees continuous playback of a plurality of content, Acquiring information necessary for reproduction and reproducing content are performed in parallel.

  Since the content playback apparatus of the present invention can start playback without acquiring information necessary for playback of all content, the responsiveness of the device to the playback operation is accelerated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a block diagram of a content reproduction apparatus according to Embodiment 1 of the present invention. In the figure, reference numeral 100 denotes the entire content reproduction apparatus, 101 denotes a memory card as a recording medium, 102 denotes file reading means, 103 denotes reproduction control means, 104 denotes content management information interpretation means, 105 denotes a buffer, and 106 denotes a decoder.

  The content reproduction apparatus 100 is an apparatus that reproduces content recorded on the recording medium 101. In the drawing, one recording medium 101 can be connected, but any number is possible. The content playback apparatus 100 includes one or more slots into which the recording medium 101 can be inserted, and playback is performed by inserting the recording medium 101 into this slot.

  When reproducing the content, the reproduction control unit 103 first reads the content management information file from the recording medium 101 using the file reading unit 102. Next, the content management information interpretation unit 104 is used to interpret the file and acquire information necessary for reproducing the content. The information necessary for reproducing the content is the time length of the content, the number of video and audio channels.

  The reproduction control unit 103 reads the content file from the recording medium 101 using the file reading unit 102 based on information necessary for reproducing the content, and stores the content file in the buffer 105. Then, the content file is read from the buffer 105 and the content is reproduced using the decoder 106. The content file in the present embodiment is a file in which the file format is Material Exchange Format (MXF) and the video file and the audio file are recorded as separate files for each channel. However, the file format may be AVI or MPEG, Audio may be recorded together in one file.

  FIG. 2 shows a directory configuration example of the recording medium 101. There is a Contents directory under the root directory, and a Clip directory, a Video directory, and an Audio directory under the Contents directory. There is a content management information file under the Clip directory. There are video files under the Video directory. There are audio files under the Audio directory.

  There is one content management information file for each content, and the file name is “content name.xml”. The content name is composed of 6 characters, and the preceding 4 characters are numbers from 0001 to 9999. This number represents the order in which contents are recorded on the recording medium 101. The last two characters are alphabets and are generated from the ID added to the content.

  There are 0 or 1 video file for each content, and the file name is “content name.mxf”.

  There are 0 to 16 audio files for each content, and the file name is “content name + channel number.mxf”. The channel number is a two-digit number, and channel number 00 corresponds to the first channel.

  Accordingly, three contents are recorded on the recording medium of FIG. 2, and the contents names are 0001AB, 0002CD, and 0003EF. The content with the content name 0001AB has one video file and two audio files. The content with the content name 0002CD has one video file and four audio files. The content with content name 0003EF has one video file and two audio files.

  FIG. 3 shows a specific example of the content management information file of FIG. In the present embodiment, the content management information is recorded on the recording medium 101 in the XML file format, but the file format may be other formats such as binary.

  Management information relating to one content is described in the ClipContent tag. The content name is described in the ClipName tag. In the Duration tag, the time length of the content is described in units of frames. Information related to video and audio of content is described in the EssenceList tag. Information about the video is described in the Video tag, and the file format of the video is described in the VideoFormat tag. Audio information is described in the Audio tag, and an audio file format is described in the AudioFormat tag. If there are multiple channels of audio, only a few audio tags are described. The order in which they are described corresponds to the audio channel numbers 1, 2,.

  FIG. 3- (1) is a content management information file whose content name is 0001AB. From the content management information file, it can be seen that the time length of the content is 10,000 frames, the video channel is 1 channel, the audio channel is 2 channels, and the video and audio file formats are both MXF. The number of video and audio files corresponds to the number of video and audio channels described in the content management information file. FIG. 3B is a content management information file whose content name is 0002CD. FIG. 3- (3) shows a content management information file whose content name is 0003CD.

  When all the contents recorded on the recording medium 101 are continuously reproduced in the recording order, the following operation is performed. This will be described with reference to the examples of FIGS.

  In order to reproduce the contents in the recorded order, the contents are reproduced in the order of the contents 0001AB, 0002CD, and 0003EF. Accordingly, the reproduction control unit 103 first reads out the content information management file having the file name “0001AB.xml” from the recording medium 101 using the file reading unit 102. Next, the content management information interpretation unit 104 interprets the file, and acquires the time length of the content and the number of video and audio channels.

  The playback control means 103 reads the video and audio files using the file reading means 102 because the file name and the time length of the video and audio files to be played back are known from the content time length and the number of video and audio channels. And stored in the buffer 105. Then, the video and audio files are read from the buffer 105 and the video and audio are reproduced using the decoder 106.

  At the same time, the content management information file of the content to be reproduced next is read out. That is, the content information management file with the file name “0002CD.xml” is read using the file reading means 102. Then, the content management information interpretation unit 104 interprets the file, and acquires the time length of the content and the number of video and audio channels. After that processing, the same processing is performed on the content 0003EF.

  When the reproduction of the content 0001AB is completed, the reproduction control unit 103 reads the video and audio files of the content 0002CD using the file reading unit 102 and stores them in the buffer 105. Then, the video and audio files are read from the buffer 105 and the video and audio are reproduced using the decoder 106. Similarly, when the reproduction of the content 0002CD is completed, the content 0003EF is reproduced.

  By performing the above processing, all the contents recorded on the recording medium 101 can be continuously reproduced in the order of recording. Further, since the reproduction can be started at the time when the content management information file of the content 0001AB is processed, the reproduction can be started earlier than the reproduction is started after the content management information files of all the contents are processed.

  However, if the data stored in the buffer 105 is lost during reproduction, the supply of data to the decoder 106 is interrupted, and the reproduction of video and audio is interrupted.

  The conditions for guaranteeing continuous reproduction will be described with reference to FIG. It is assumed that there are N contents to be reproduced, the minimum value of the time length of the content is M [sec], the time taken to read and interpret the content management information file is T [sec], and the time length of the content to be reproduced first Is D [sec]. Further, a process of reading the content management information file from the recording medium 101 is S1, a process of interpreting the content management information file is S2, and a process of reading the content file from the recording medium 101 and storing it in the buffer 105 is S3. Since the processes of S1 and S3 access the same recording medium, they cannot be performed simultaneously. Further, the process of S3 cannot be performed unless the processes of S1 and S2 are completed. Therefore, processing is performed in the order of S1, S2, and S3.

  First, the processing of S1, S2, and S3 is performed on the content to be reproduced first. Data supply from the buffer 105 to the decoder 106 is started when the processing of S3 is performed for one frame, and thereafter data is supplied at a reproduction data rate until the reproduction is completed. The decoder 106 is assumed to have a capability of decoding data supplied at a reproduction data rate in real time, and immediately outputs the decoded video and audio. The reproduction control means 103 reads the content data from the recording medium 101 and stores it in the buffer 105 in terms of frame conversion / time, V1 [frame / sec], and the speed at which data is supplied from the buffer 105 to the decoder 106. A value expressed in frame conversion / time is defined as V2 [frame / sec].

  When the processing of S3 for the content to be reproduced first is completed, the processing of S1, S2 and S3 is performed for the content to be reproduced second, and thereafter the same processing is performed up to the content to be reproduced Nth.

Since the time length of the second and subsequent contents is not known unless the processing of S1 and S2 is performed, it is assumed that the shortest content time length M [sec], which is the most severe condition for continuous reproduction, is used. Then, as can be seen from the data amount of the buffer 105 in FIG. 4, if the remaining capacity of the buffer 105 is 1 frame or more immediately after the processing of S1 and S2 is performed on the Nth content, continuous playback of all the contents is guaranteed. Will be. Therefore, continuous reproduction is guaranteed if D [sec] satisfies the following expression.
V1 (D + M (N−2)) − V2 (D−1 / V1 + T (N−1) + M (N−2)) ≧ 1 [frame]
The first term on the left side is the total amount of data stored in the buffer 105 at the stage when the processing of S1 and S2 is performed on the Nth content, and the second term on the left side is supplied from the buffer 105 to the decoder 106 at the stage. The total amount of data collected. If the difference between the first term and the second term is 1 frame or more, continuous reproduction is guaranteed. In the 0 frame, the supply of data to the decoder 106 is interrupted, so one or more frames are required.

  If the above equation cannot be satisfied and continuous playback cannot be guaranteed, the processing of S1 and S2 is performed on the content to be played back first, and then the processing of S3 is not performed. The processes of S1 and S2 are performed on the contents after the th. If the condition for continuous reproduction is satisfied, the process of S3 is performed on the content that has not been subjected to the process of S3, and decoding and reproduction are started. The conditions for continuous reproduction in this case will be described with reference to FIG. It is assumed that the number of contents subjected to the processing of S1 and S2 is n, and the total time length of the contents is d [sec].

Since the time length of the (n + 1) th and subsequent contents is not known unless the processes of S1 and S2 are performed, the shortest content time length M [sec], which is the most severe condition for continuous playback, is assumed. Then, as can be seen from the data amount of the buffer 105 in FIG. 5, if the remaining capacity of the buffer 105 is one frame or more immediately after the processing of S1 and S2 is performed on the Nth content, continuous playback of all the contents is guaranteed. Will be. Therefore, continuous reproduction is guaranteed if n and d [sec] satisfy the following expression.
V1 (d + M (N−n−1)) − V2 (d−1 / V1 + T (N−n) + M (N−n−1)) ≧ 1 [frame]
The first term on the left side is the total amount of data stored in the buffer 105 at the stage when the processing of S1 and S2 is performed on the Nth content, and the second term on the left side is supplied from the buffer 105 to the decoder 106 at the stage. The total amount of data collected. If the difference between the first term and the second term is 1 frame or more, continuous reproduction is guaranteed.

  If the capacity of the buffer 105 is not sufficient, the overflow of the buffer 105 is performed by performing the processing of S1 and S2 of the n + 1th and subsequent contents while the processing of S3 is performed on the first to nth contents. May be prevented.

  Processing until playback is started will be described with reference to FIG. FIG. 6 is a flowchart showing the above process. First, the total number of contents recorded on the recording medium 101 is acquired and set to N, and d (sec) is set to 0 (zero) (step S11). The total number of contents is obtained by obtaining a file list recorded in the Clip directory of the recording medium 101 using the file reading unit 102 and obtaining the number of content management files from the file list. If N is 0 (zero), there is no content to be played back, and the process is terminated (step S12).

Next, one content management information file is processed. The time length of the acquired content is added to d [sec], and n is incremented by 1 (step S13). The conditional expression V1 (d + M (Nn-1))-V2 (d-1 / V1 + T (Nn) + M (Nn-1)) ≥1 [frame]
If true, the process is terminated because continuous playback is guaranteed, and if false, the process of the content management information file is repeated (step S14).

  In the present embodiment, the contents are reproduced in the order in which the contents are recorded on the recording medium 101. However, the contents may be reproduced in any order, for example, in the order of reproduction specified by the user like a playlist. good.

(Embodiment 2)
The configuration of content reproduction apparatus 100 in the second embodiment of the present invention is the same as that in the first embodiment. This embodiment is different from the previous embodiments in that content is recorded across a plurality of recording media, and the relationship between the contents is described in the content management information file.

  An example of the directory structure of the recording medium 101 in the present embodiment is shown in FIG. A recording medium ID is attached to the recording medium, A is attached to the recording medium 201, and B is attached to the recording medium 202. Three contents are recorded on the recording medium 201, and the contents names are 0001AB, 0002CD, and 0003EF. One content is recorded on the recording medium 202, and the content name is 0001GH. It is assumed that the content 0002CD of the recording medium 201 and the content 0001GH of the recording medium 202 are recorded across the recording medium, and the content 0002CD and the content 0001GH are recorded in this order.

  FIG. 7 shows a content management information file description example of the contents 0002CD and 0001GH.

  FIG. 8- (1) is a content management information file of the content 0002CD. Information of content recorded on another recording medium is described in the Relation tag. Information on the content recorded next to this content is described in the Next tag. The clip name is described in the ClipName tag. P2 Serial No. A recording medium ID is described in the tag. FIG. 8- (2) is a content management information file of the content 0001GH. Information of the content recorded before this content is described in the Previous tag.

  By describing in this way, if FIG. 8- (1) is interpreted, the content 0002CD is a content recorded across a plurality of recording media, and the content recorded next to the content 0002CD has a recording medium ID. It can be seen that the content name 0001GH is recorded on the recording medium B. Further, when interpreting FIG. 8- (2), the content 0001GH is the content recorded across a plurality of recording media, and the content recorded before the content 0001GH is recorded on the recording medium whose recording medium ID is A. It can be seen that the content name is 0002CD.

  When all the contents recorded on the recording medium 201 are continuously reproduced in the order of recording, the following operation is performed. This will be described with reference to the examples of FIGS.

  The reproduction process of the content 0001AB is the same as that in the first embodiment. In the reproduction process of the content 0002CD, when the content management information file is interpreted using the content management information interpretation unit 104, the content 0002CD is a content recorded across a plurality of recording media, and the content recorded next to the content 0002CD Is recorded on the recording medium whose recording medium ID is B with the content name 0001GH. Therefore, in the first embodiment, the content management information file of the content 0003EF is processed next, but in this embodiment, the content management information file of the content 0001GH recorded on the recording medium 202 is processed. Next, the content management information file of the content 0003EF is processed. The order in which the contents are reproduced is contents 0001AB, 0002CD, 0001GH, and 0003EF.

  By performing the above processing, all the contents recorded on the recording medium 201 can be continuously reproduced in the order of recording, including the contents recorded across a plurality of media.

  Since the content reproduction apparatus according to the present invention can start reproduction without acquiring information necessary for reproduction of all content, a recording medium on which information necessary for content reproduction is recorded as a separate file for each content This is useful for a content playback apparatus that plays

Block diagram of Embodiments 1 and 2 of the present invention The figure which showed the example of a directory structure of Embodiment 1 of this invention The figure which showed the example of the content management information file of Embodiment 1 of this invention The figure which showed the change of the data amount of the buffer 105 of Embodiment 1 of this invention. The figure which showed the change of the data amount of the buffer 105 at the time of processing a content management information file until the conditions of continuous reproduction are satisfy | filled in Embodiment 1 of this invention. The figure which showed the process until it starts the reproduction | regeneration of Embodiment 1 of this invention with the flowchart. The figure which showed the example of a directory structure of Embodiment 2 of this invention The figure which showed the example of the content management information file of Embodiment 2 of this invention Block diagram of a conventional video data management device

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Content reproduction apparatus 101 Recording medium 102 File reading means 103 Playback control means 104 Content management information interpretation means 105 Buffer 106 Decoder 201 Recording medium 202 Recording medium 901 CPU
902 Input / output timing control means 903 Header table management means 904 Accumulated data management means 905 Buffering means 906 Data distribution means

Claims (6)

File reading means for reading a file from a recording medium;
Content management information interpretation means for interpreting content management information recorded for each content in the recording medium;
A buffer for storing data of the content read from the recording medium;
A decoder for decoding the content data;
Content for which the information necessary for reproducing the content is obtained from the content management information using the content management information interpreting means, the content management information is read from the recording medium and interpreted, in the order of reproduction of the plurality of contents The number n, the total content time length corresponding to the content number n is d [sec], the number of content to be reproduced is N, the minimum content time length is M [sec], and the reproduction control means is the content The time taken to read the management information from the recording medium and interpret it using the content management information interpreting means is T [sec], and the speed at which the reproduction control means reads the content from the recording medium and stores it in the buffer is V1 [ Frame / sec], and the rate at which data is supplied from the buffer to the decoder is V2 D = M (N−n−1)) − V2 (d−1 / V1 + T (N−n) + M (N−n−1)) ≧ 1 [frame] The information necessary for reproduction of the content is obtained using the content management information interpretation means from the content management information of the content for which the information necessary for reproduction is not obtained and the information necessary for reproduction is obtained. And playing control means for playing back the plurality of contents without interruption,
A content playback apparatus comprising: The content reproduction apparatus according to claim 1, wherein the content management information is recorded in a file different from the content file. The content playback apparatus according to claim 2, wherein a content name is assigned to the content, and the content name is included in a file name of the content file and a file name of the content management information file. The content playback apparatus according to claim 1, wherein the content includes one video file and one or more audio files. The content management information is recorded in each of the contents that are divided and recorded, and the content management information is also recorded with information about the other divided contents. Information about the other divided content can be interpreted, and the reproduction control means acquires information on the other divided content using the content management information interpreting means, and the division information is obtained from the information about the other divided content. 2. The content reproducing apparatus according to claim 1, wherein the information necessary for reproducing the other content is acquired, and the content divided and recorded is reproduced without interruption. The content reproduction apparatus according to claim 5, wherein the content divided and recorded is recorded on the plurality of recording media.

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