JP2007295464A - Reproducing apparatus, reproducing method, and reproducing program of optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reproducing apparatus of optical recording medium that can reduce capacity of the buffer. <P>SOLUTION: The present invention relates to a reproducing apparatus for reproducing optical recording medium including AV stream and one or more caption data. This reproducing apparatus is provided with a local storage for storing one or more caption data recorded in the optical recording medium, a caption data buffer for storing one caption data among one or more caption data stored in the local storage, an AV data buffer for storing the AV stream recorded in the optical recording medium, and a reproducing unit for synchronously reproducing one caption data stored in the caption data buffer and the AV stream stored in the AV data buffer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a reproducing apparatus, a reproducing method, and a reproducing program for an optical recording medium for reproducing information recorded on the optical recording medium. In particular, the present invention relates to a playback device capable of displaying subtitles, a playback method, and a playback program.

  In the DVD (Digital Versatile Disc) standard, there is a DVD-Video format as a reproduction-only standard using an optical disk. In the DVD-Video format, video data and audio data, as well as subtitle data and the like are multiplexed and recorded on the disc. However, in the DVD-Video format, only video, audio, subtitle data, etc. recorded in advance on the disc can be reproduced.

  On the other hand, there is a playback device that has a network connection function or a local storage that enables data recording. According to this playback apparatus, additional data such as video, audio, subtitles, and fonts can be downloaded to a local storage via a network, and a video composed of the downloaded data can be viewed (for example, see Patent Document 1). .)

  In other words, in order to enable subtitle display in a language not recorded on the optical disc, the network connection function is used to download data related to subtitles in different languages from a resource on the network to the local storage. It can be reproduced in synchronization with a video / audio stream (hereinafter referred to as “AV stream”).

Japanese Patent Laying-Open No. 2005-269595 (pages 11 to 14, FIG. 1)

  In general, an optical disc has a slower access speed than a local storage. Therefore, it is difficult to read out the AV stream recorded on the optical disc and the data related to the caption while synchronizing them. Therefore, data relating to captions that are smaller in capacity than the AV stream is generally read (preloaded) into a buffer in advance before optical disc playback.

  However, when playing back an optical disc in which a plurality of languages are recorded, in order to switch between a plurality of subtitle display languages without interrupting the playback of the AV stream, the subtitle data for all the recorded languages is buffered. Need to hold on. Therefore, there is a problem that the required buffer capacity is increased.

  The present invention has been made in view of the above problems, and an object thereof is to provide an optical recording medium reproducing apparatus capable of reducing the buffer capacity.

An optical recording medium reproducing apparatus according to the present invention includes:
A playback device that plays back an optical recording medium in which an AV stream and one or more caption data are recorded,
A local storage for storing one or more caption data recorded on the optical recording medium;
Of the one or more subtitle data stored in the local storage, a subtitle data buffer that stores one subtitle data,
An AV data buffer for storing an AV stream recorded on the optical recording medium;
A playback section for synchronizing and playing back one caption data stored in the caption data buffer and an AV stream stored in the AV data buffer is provided.

  According to the optical recording medium reproducing apparatus of the present invention, it is sufficient if there is a buffer having a capacity capable of storing one caption data. Therefore, there is an effect that the subtitle display can be changed without interrupting video / audio reproduction while reducing the buffer capacity.

Embodiment 1 FIG.
The playback device of the optical recording medium (hereinafter referred to as “optical disk”) according to the present embodiment temporarily stores a plurality of types of caption data recorded on the optical disk in a local storage. Then, the data is read from the local storage to the buffer as appropriate.

  FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention. In the figure, 1 is a controller, 2 is a virtual file system, 3 is a cache controller, 4 is local storage, 5 is an optical disk drive, 6 is an AV buffer, 7 is an AV decoder, 8 is a caption buffer, 9 is a caption decoder, 10 Is a font buffer (“subtitle data buffer” is composed of “subtitle buffer” and “font buffer”), 11 is a video synthesizer, and (“playback unit” is composed of “AV decoder” and “subtitle decoder”. Note that “video synthesizer” may be added, or a concept including “controller” may be added.) 12 is an operation receiving unit. These will be described below.

  The controller 1 has a role of controlling the entire playback apparatus, reads data from the optical disk drive 5 and the local storage 4 through the virtual file system 2, controls synchronous playback of the AV decoder 7 and the caption decoder 9, and a cache controller. 3, the user's operation input information from the operation receiving unit 12 is received and processing corresponding to input such as playback / stop / subtitle language switching is performed.

  The virtual file system 2 has a function of combining and managing file update data, which will be described later, stored in the local storage 4 through the cache controller 3 and information recorded in both devices of the optical disk drive 5 and managing them centrally. The controller 1, the AV buffer 6, the caption buffer 8, and the font buffer 10 that receive data from or write data to the virtual file system 2 are conscious of whether the data belongs to the local storage 4 or the optical disk drive 5. Can work without.

  The cache controller 3 can access the optical disk drive 5 and the local storage 4 to read and write streams and data. Here, the subtitle text substream and the font data are collectively referred to as subtitle data. The cache controller 3 stores subtitle data existing in the optical disk drive 5 in the local storage 4 in response to an instruction from the controller 1, and responds to a subsequent read request for subtitle data existing in the optical disk drive 5 on the optical disk drive 5. Instead of the caption data, the caption data stored in the local storage 4 is read and passed to the virtual file system 2. The subtitle data once stored is erased by an instruction from the cache controller 3.

  The local storage 4 holds file update data that is data for updating and adding a file in the optical disc set in the optical disc drive 5 by a network connection function (not shown), and subtitle data input by the cache controller 3. The local storage 4 is divided into a file update data area and a cache area. The file update data uses the file update data area, and the caption data uses the cache area. The file update data is centrally managed by the virtual file system 2 together with the files in the optical disc set in the optical disc drive 5.

  The optical disk drive 5 reads the video / audio stream, the subtitle text substream, and the like from the optical disk in which the content including the video / audio stream and the subtitle text substream is recorded.

  The AV buffer 6 is a temporary storage area that temporarily holds the video / audio stream read from the virtual file system 2 by the controller 1 until it is read from the AV decoder 7. Since the video / audio stream has a large capacity, it is difficult to store all the video / audio streams necessary for reproduction in the AV buffer 6. Therefore, the controller 1 subdivides the video / audio stream to some extent and periodically reads it out to the AV buffer 6. At this time, the controller 1 does not lose the video / audio stream in the AV buffer 6 and the decoding by the AV decoder 7 is interrupted, or the video / audio stream is excessively supplied to the AV buffer 6 and overflows. Control is performed as appropriate.

  The AV decoder 7 receives an instruction from the controller 1, reads out the video / audio stream held in the AV buffer 6, and performs decoding according to the timing described in the video / audio stream. Control such as the start, end, and pause of decoding is instructed by the controller 1.

  The caption buffer 8 is a temporary storage area that temporarily holds a caption text substream that is one of the constituent elements of caption data read from the virtual file system 2 by the controller 1. Since the subtitle text substream has a smaller capacity than the video / audio stream, the controller 1 reads only the subtitle text substream of the currently required language into the subtitle buffer 8 before starting the reproduction. When the subtitle language is changed by the user's operation, the subtitle text substream of the newly selected language is read from the virtual file system 2. The subtitle text substream read out at this time is not in the optical disc drive 5 but is a subtitle text substream held in the local storage 4 by the cache controller 3. The audio stream is not affected and the reproduction of the video / audio stream is not interrupted.

  The font buffer 10 is a temporary storage area that temporarily holds font data that is one of the constituent elements of caption data read from the virtual file system 2 by the controller 1. Similarly to the subtitle text substream, the font data has a smaller capacity than the video / audio stream, so the controller 1 reads out only the font data of the currently required language into the font buffer 10 before starting the reproduction. . When the subtitle language is changed by the user's operation, the font data of the newly selected language is read from the virtual file system 2. The font data read at this time is not in the optical disk drive 5 but is font data held in the local storage 4 by the cache controller 3, so that the video / audio stream read from the optical disk drive 5 is affected. The video / audio stream playback is not interrupted.

  The subtitle decoder 9 receives an instruction from the controller 1, reads the subtitle text substream held in the subtitle buffer 8, and performs decoding according to the timing described in the subtitle text substream. In the subtitle text sub-stream, character information is described as a symbol instead of a video, so that the video information corresponding to the symbol is read out from the font data held in the font buffer 10 to be visualized.

  The video synthesizer 11 superimposes the video output from the caption decoder 9 on the video output from the AV decoder 7 and synthesizes it into one video.

  The operation receiving unit 12 informs the controller 1 of user operation information such as playback / stop / subtitle language switching using a remote controller or a main body key. The controller 1 receives information from the operation receiving unit 12 and controls each block to perform operations such as playback / stop / subtitle language switching based on the operation information.

  In the first embodiment, the local storage 4 is described assuming that it is built in the apparatus, but it may be removable. In that case, in the virtual file system 2 and the cache controller 3, if the local storage 4 exists, the local storage 4 is used, and if not, the local storage 4 is not used and only the optical disk drive 5 is used.

  Next, the mechanism until content reproduction, particularly caption reproduction, is mainly described. Content reproduction is performed by designating a playlist and reproducing the playlist.

  First, FIG. 2 shows the structure of a playlist. The playlist is composed of a main item describing information related to reproduction of video / audio, which is a main element of content, and a subtrack describing information related to reproduction of subtitles. There may be a plurality of main items and sub-tracks. When there are a plurality of main items, it indicates that they are played in order. When there are a plurality of sub-tracks, it indicates that there are several selectable tracks, and any one of these can be selected and reproduced. In the playlist of FIG. 2, there are Nm main items and Nt sub-tracks.

  The main item is a clip information in which video / audio stream information to be reproduced is described, a start time in which a reproduction start time is described, an end time in which a reproduction end time is described, and a stream that collects stream information related to the main item It consists of a table. The stream table stores video stream information describing information related to the video stream, audio stream information describing information related to the audio stream, and subtitle text stream information describing information related to the subtitle text stream. In the subtitle text stream information, a subtrack number and subtitle language information in the subtrack are written as a set. By referring to the subtitle text stream information, the subtitle language that can be selected in the main item to be played back can be obtained. By presenting the subtitle language that can be selected to the user, the user's current subtitle language can be obtained. You can know the desired subtitle language.

  In the subtrack, subitems in which information related to reproduction of individual captions is described are described. There may be multiple sub-items. There are Ns sub-items in sub-track # 1 in FIG. The sub-item stores clip information describing information related to subtitle text, a start time describing a playback start time, and an end time describing a playback end time. The clip information includes a subtitle text stream in which information about a stream in which subtitle text is stored is described, and font data information in which information on fonts used in the subtitle text stream is described. In order to obtain a file to be preloaded when the sub-item is reproduced, the subtitle text stream file name may be referred to from the subtitle text stream information, and the font data file name may be referred to from the font data information. The configuration of the playlist, particularly the configuration related to the subtitles, has been described above.

  Next, a procedure until subtitle reproduction is performed will be described. FIG. 3 shows a subtitle reproduction start procedure in the controller 1. In FIG. 4, in step S11, subtitle data to be described later is copied (FIG. 4). Subsequently, in step S12, a subtitle display instruction from the user is awaited. When there is a caption display instruction from the user, a caption language acquisition process described later is performed in step S13 (FIG. 5).

  In step S14, the user is prompted to select a caption language, and the caption language selected by the user is determined. In this case, the subtitle language is always selected by the user. However, if the subtitle language that the user wants to use is determined in advance and the subtitle language can be displayed, the subtitle language is automatically selected. The subtitle language may be determined.

  In step S15, reproduction start processing of a subtitle text stream corresponding to the subtitle language selected by the user in step S14 is performed (FIG. 6). The above is the description of FIG.

  Next, a procedure for obtaining information related to subtitles from the playlist and preparing for subtitle reproduction, that is, a procedure for acquiring subtitle data information from the playlist and copying the subtitle data to the local storage 4 will be described. FIG. 4 illustrates a processing procedure for performing subtitle data copying in the controller 1.

  In step S21, the play list to be reproduced is opened. In step S22, the presence / absence of a subtrack in the playlist is checked. If there is a subtrack, the process proceeds to step S23. If there is no subtrack, the process proceeds to step S29.

  In step S23, a sub item in the sub track is acquired, and the process proceeds to step S24. In step S24, the subtitle text stream file name is acquired from the subtitle text stream information described in the clip information in the subitem. In step S25, the font data file name is acquired from the font data information described in the clip information in the sub item.

  Next, in step S26, the subtitle text stream file name and the font data file name are passed from the controller 1 to the cache controller 3, and the cache controller 3 accesses the same name file existing in the optical disc drive 5 to each file. Get the size and add these file sizes. Further, the cache controller 3 accesses the local storage 4 to acquire the free capacity, compares the total file size previously with the free capacity of the local storage 4, and if the free capacity of the local storage 4 is large, the controller 1 Returns copyable, otherwise returns copy impossible. If the response of the cache controller 3 can be copied, the controller 1 proceeds to step S27. If the response cannot be copied, the controller 1 proceeds to step S28.

  In step S27, a copy command is issued from the controller 1 to the cache controller 3, and the cache controller 3 performs file copy from the optical disk drive 5 to the cache area of the local storage 4 according to the file name transmitted in step S26. Is done. In step S28, the sub-track to be processed is advanced by one, the next sub-track is set as the processing target, and the process returns to step S22 again.

  In step S22, the presence / absence of the sub-track currently being processed is evaluated again. The above process is repeated until there are finally no subtracks. In step S22, when there are no more subtracks, the process proceeds to step S29, the playlist is closed, and the subtitle data copy process ends.

  FIG. 5 illustrates a subtitle language acquisition procedure in the controller 1. In the figure, in step S31, the playlist being reproduced is opened. In step S32, the main item currently reproduced is acquired from the playlist. Subsequently, in step S33, all sub-track numbers and language information are acquired as a set from the subtitle text stream information described in the stream table in the main item. In step S34, the playlist opened in step S31 is closed.

  FIG. 6 shows the subtitle text stream playback start procedure in the controller 1. In the figure, in step S41, the playlist being reproduced is opened. Subsequently, in step S42, the subtrack corresponding to the caption language selected by the user in step S14 in FIG. 3 is determined from the subtrack number and language information acquired in step 33 in FIG.

  In step S43, based on the time information of the currently reproduced video / audio stream, a sub-item corresponding to the time is acquired. In step S44, the subtitle text stream file name and font data file name are acquired from the clip information in the subitem. In step S45, the subtitle text stream file and font data file are read from the virtual file system 2 based on the file name acquired in step S44, the subtitle text stream file is transferred to the subtitle buffer 8, and the font data file is transferred to the font buffer 10. Forward to.

  In step 46, the controller 1 instructs the subtitle decoder 9 to start decoding, and subtitle playback is started. Finally, in step S47, the playlist is closed.

  Up to this point, the procedure in the controller 1 has been mainly shown, but the cache controller 3 plays a major role in reading and writing subtitle data. Therefore, a management method of the cache area in the local storage 4 managed by the cache controller 3 and its management procedure will be described.

  FIG. 7 shows a cache cache management table in the local storage 4 managed by the cache controller 3. In the figure, the cache management table is divided into two ID units: area information recording the usage status of the cache area, an organization ID assigned to each content provider, and a disk ID assigned to each content. Information of files sharing the same organization ID and disk ID is listed following the organization ID and disk ID.

  The area information includes a free area size in which the free area of the cache area is recorded and an area map indicating which part of the area is used and where it is free. In order to add a new file, the free area size must be larger than the file size to be added, and the actual area to be used must be allocated by searching for unused areas using the area map. is there.

  The file information includes a file name to be stored, a size indicating the size of the file, and a start area position indicating from which part of the cache area the data is stored.

  Next, a procedure for writing and deleting a file in the cache area is shown. First, FIG. 8 shows a processing procedure of the cache controller 3 when adding a file to the cache area. In the figure, in step S51, the size of the file to be added is compared with the free area size described in the area information. If the free area size is not smaller, the process proceeds to step S52. Otherwise, the process ends. In step S52, the organization ID and disk ID of the file to be added are compared with the organization ID and disk ID described in the cache management table. If the same is found, the process proceeds to step S53, otherwise. Proceed to step S54.

  In step S53, the file name belonging to the organization ID and disk ID found in step S52 is compared with the file name to be added, and if there is an identical file, the process ends. Otherwise, the process proceeds to step S55. In step S54, the organization ID and disk ID of the file to be added are newly added, and the process proceeds to step S55.

  In step S55, an empty area is found from the area map in the area information, an area for the file size to be added is secured, the area is set as a use area, and the data in the file is copied to the corresponding area. Also, a value corresponding to the file size to be added is subtracted from the free area size. Further, the secured start area position is temporarily stored as information for adding file information to be described later until the file information is added.

  In step S57, file information belonging to the organization ID and disk ID newly found in step S52 or newly added in step S54 is newly added, and the file name, size, and start area position stored in step S55 are stored. Set.

  Next, FIG. 9 shows a processing procedure of the cache controller 3 when deleting a file from the cache area. In the figure, in step S61, it is checked whether there is the same file as the organization ID and disk ID of the file to be deleted. If it exists, the process proceeds to step S62, and if not, the process ends. In step S62, it is checked whether or not the file information belonging to the weave ID and disk ID found in step S61 has the same file name as the file name to be deleted. If the same file name exists, the process proceeds to step S63, and if not, the process ends.

  In step S63, the area occupied by the file to be deleted on the area map is cleared and made unused. In step S64, the file size of the file to be deleted is added to the free area size. In step S65, the file information of the file to be deleted is deleted.

  In step S66, it is checked whether the file information belonging to the organization ID and disk ID found in step S61 has disappeared because the file information has been deleted in S65. If there is no file information, the process proceeds to S67 to indicate that there is no more file related to the organization ID and disk ID. If not, exit. In step S67, the organization ID and disk ID found in step S61 are deleted and the process ends. The above is the description of FIG.

  In addition, FIG. 10 shows a procedure in which the cache controller 3 refers to the file. In step S71, it is checked whether the local storage 4 exists. If the local storage 4 exists, the process proceeds to step S72, and if not, the process proceeds to step S75. In step S72, it is checked whether or not there is the same file as the organization ID and disk ID of the file to be referred to. If it exists, the process proceeds to step S73, and if not, the process proceeds to step S75. In step S73, it is checked whether the file information belonging to the organization ID and disk ID found in step S72 has the same name as the file name to be referred to. If the same file name exists, the process proceeds to step S74, and if not, the process proceeds to step S75. In step S74, the file data found in step S73 is read and the process ends. Step S75 is a process performed when the local storage 4 does not exist or when the corresponding file does not exist in the cache area in the local storage 4, and the process ends after reading the corresponding file in the optical disc.

  Note that the lifetime of data in the cache area may be until the optical disk is ejected, or may be stored after the optical disk is ejected as long as the area permits. As the former advantage, only the caption data recorded on one optical disk needs to be held, so that the cache area can be made relatively small and at the same time the management by the organization ID and the disk ID can be omitted. It becomes easy. As an advantage of the latter, since the already stored subtitle data can be reused, it is not necessary to read the subtitle data in the optical disc, and the time until the start of reproduction after the second and subsequent disc insertion is shortened.

  As an effect of the first embodiment, the subtitle data for subtitle display is not read into the preload buffer before starting the reproduction of the video / audio, but is temporarily cached in the cache area in the local storage, When new subtitle data is read due to changes, cached data is provided in the local storage, so if there is a preload buffer that can read only the subtitle data that should be displayed, video and audio can be played back. Subtitles can be changed without interrupting and the buffer can be reduced. For a single subtitle language, a subtitle text stream requires a buffer of up to 512 kB and font data of up to 4 MB. Therefore, the more subtitle languages that can be selected, the greater the buffer reduction effect in the first embodiment. Will grow.

  Furthermore, as an effect of this embodiment, the subtitle data for subtitle display is not read into the preload buffer before starting the playback of video / audio, but is cached in the local storage, and the new subtitle data is changed by changing the subtitle language, etc. When subtitle data is read, if there is a preload buffer that can read only subtitle data, subtitles can be changed without interrupting video / audio playback, so the preload buffer can be reduced. .

  As a configuration of the present embodiment, the presence or absence of a local storage or the presence or absence of a file in the local storage may be detected, or the local storage may be detachable. As a result, there is no cost for local storage when manufacturing the playback device, so there is an effect that the cost can be reduced, and for the user, playback is interrupted by adding local storage. There is an effect that it is possible to add a function that can change the subtitle language without any change.

  Moreover, although the case where subtitle data is in different languages has been described in the present embodiment, for example, subtitle data of main audio and sub audio in the same language may be used. That is, different types of caption data may be used.

It is a block diagram which shows Embodiment 1 of this invention. 6 is an explanatory diagram illustrating a configuration of a playlist according to Embodiment 1. FIG. 3 is a flowchart showing a subtitle reproduction start procedure in the first embodiment. 4 is a flowchart illustrating a subtitle data copy procedure according to the first embodiment. 6 is a flowchart illustrating a subtitle language acquisition procedure according to the first embodiment. 6 is a flowchart showing a subtitle text stream reproduction start procedure in the first embodiment. 4 is an explanatory diagram illustrating a configuration of a cache management table according to the first embodiment. FIG. 4 is a flowchart showing a file addition procedure in the first embodiment. 5 is a flowchart showing a file deletion procedure in the first embodiment. 5 is a flowchart showing a file reference procedure in the first embodiment.

Explanation of symbols

1 controller, 2 virtual file system, 3 cache controller, 4 local storage, 5 optical disk drive, 6 AV buffer, 7 AV decoder, 8 subtitle buffer, 9 subtitle decoder, 10 font buffer, 11 video synthesizer, 12 operation receiver.

Claims (8)

A playback device that plays back an optical recording medium in which an AV stream and one or more caption data are recorded,
A local storage for storing one or more caption data recorded on the optical recording medium;
Of the one or more subtitle data stored in the local storage, a subtitle data buffer for storing one subtitle data;
An AV data buffer for storing an AV stream recorded on the optical recording medium;
A playback device for an optical recording medium, comprising: a playback unit that plays back one caption data stored in the caption data buffer and an AV stream stored in the AV data buffer in synchronization. The subtitle data includes a subtitle text substream and font data.
2. The reproducing apparatus for an optical recording medium according to claim 1, wherein the subtitle data buffer includes a subtitle buffer for storing the subtitle text substream and a font buffer for storing the font data. 3. The optical recording medium reproducing apparatus according to claim 1, wherein the one or more subtitle data is subtitle data having different languages. 4. The optical recording medium reproducing apparatus according to claim 1, wherein the local storage is detachable from the optical recording medium reproducing apparatus. 5. A reproduction method for reproducing an optical recording medium in which an AV stream and one or more subtitle data are recorded,
A first storage step of storing in the local storage one or more subtitle data recorded on the optical recording medium;
A second storage step of storing one subtitle data among the one or more subtitle data stored in the local storage in a subtitle data buffer;
A third storage step of storing an AV stream recorded in the optical recording medium in an AV data buffer;
A reproduction method of an optical recording medium, comprising: a reproduction step of reproducing one subtitle data stored in the subtitle data buffer and an AV stream stored in the AV data buffer in synchronization. The subtitle data includes a subtitle text substream and font data.
6. The method of reproducing an optical recording medium according to claim 5, wherein the subtitle data buffer includes a subtitle buffer for storing the subtitle text substream and a font buffer for storing the font data. The method for reproducing an optical recording medium according to claim 5, wherein the one or more subtitle data is subtitle data having different languages. A reproduction program for reproducing an optical recording medium in which an AV stream and one or more caption data are recorded,
A first storage step of storing, in a local storage, one or more subtitle data recorded on the optical recording medium;
A second storage step of storing one subtitle data among the one or more subtitle data stored in the local storage in a subtitle data buffer;
A third storage step of storing an AV stream recorded in the optical recording medium in an AV data buffer;
A reproduction program for an optical recording medium, comprising: a reproduction step for reproducing one piece of subtitle data stored in the subtitle data buffer and an AV stream stored in the AV data buffer in synchronization.

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