JP2008263502A - Recording and reproducing device and recording and reproduction system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital broadcast recording and reproducing device which meets a user's unexpected viewing desire recalled by a recommendation from a third person, retrieves a compressed video stream, without causing violation of rights of a right holder and without decoding the compressed video stream and quickly provides the user with only a corresponding scene of high quality, as it is. <P>SOLUTION: The digital broadcast recording and reproducing device is provided with a signature file generating means 210 for generating signature information from an I picture of received MPEG video stream data, by utilizing a hash function; a playlist generating means 212 for generating a playlist by using the signature information; a playlist inputting and outputting means 213 for outputting the generated playlist to another device and receiving a playlist generated by the other device; and a playlist reproducing means 214 for extracting reproduction object data from a recorded MPEG stream, on the basis of the received playlist to reproduce the reproduction object data. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a recording / reproducing apparatus and a recording / reproducing system capable of recording digital broadcast program data and reproducing the data based on a playlist.

  The capacity of storage media in recording and reproducing devices that have been widely used in the past has been increasing year by year, and in particular, the capacity of hard disk drives (HDD) has been increasing at a rate of about twice a year.

  Recording and playback devices similar to HDD recorders equipped with 250 to 1000 gigabyte hard disk drives are already on the market, which are SDTV (Standard Definition Television) quality content over 100 hours and HDTV quality content over 50 hours. Since it can be recorded as described above, it can be easily estimated that a recording / reproducing apparatus capable of recording HDTV quality content for several hundred hours after several years will be commercially available.

  However, even if it can be recorded for 1,000 hours, the amount that can be viewed naturally is limited unless the user's disposable time (time for viewing the recorded content) is increased. In applications where content recording is actively instructed (recording reservation for television program content), the storage capacity is considered sufficient.

  As a function for effectively utilizing such a recording / reproducing apparatus having a huge storage capacity, the recording / reproducing apparatus automatically acquires and records the content without waiting for the user's reservation recording instruction (in TV program content). If there is an automatic recording or an automatic recording to be performed, the user can search and view desired content as necessary after the automatic recording or the automatic recording.

  In such automatic recording / automatic recording, a content search method is important.

  To search for the content recorded on the current HDD recorder, list the title name and recording start date / time associated with the recorded content, and thumbnail images processed from the content, vertically or horizontally on the screen. A list display method that presents the information in a form and allows the user to select and input the data is the mainstream.

  However, such a content search method has the following problems.

(1) Complexity of browsing and searching If the above-described content searching method is applied to hundreds to thousands of automatically recorded television program contents, it takes a huge amount of time until the user finds the desired contents. It is not effective because it is clear that it will take and fail.

(2) The word-of-mouth effect is difficult to use In recent years, the introduction of digital broadcasting systems, the spread of information data compression technology, the spread of digital broadcast recording / playback devices for individual users, and the spread of the Internet, etc. The style has changed, and the recorded TV program content is less likely to be seen from the beginning to the end, and recommendations (recommended from communication with an unspecified number of third parties through telephone calls, e-mails, or Internet electronic bulletin boards from friends, etc. ) Zapping viewing one scene of the content that has been added.

  For example, a third party registered on an electronic bulletin board, “There was such a scene (B) in a variety program (A) of a broadcasting station (N) aired on December 20 (D), and I laughed so much” There is a scene that suddenly recalls the desire to read the registered text and see it.

  This is a word-of-mouth effect through the Internet, which can provide a new viewing style compared to the conventional viewing style of recording and viewing only the programs that you really want to watch, and use such an electronic bulletin board This makes it possible to communicate with other people in different places on a common topic of television programs.

  However, in current HDD recorders and VDRs (video disc recorders), using the above list display method, the broadcast station name (N), title name (A), and recording start date and time (D) from the automatically recorded content list. The video stream file of the variety program can be searched for, but the scene (B) in the program cannot be specified precisely, so the content is searched in response to the sudden desire as described above. It is difficult.

  For this reason, the user needs to view all contents from the beginning of the content, and is forced to perform long-time viewing and cumbersome operations such as heading operation.

(3) Copyright / Portrait Issues In order to supplement the word-of-mouth effect as described above, a certain user shoots all or part of the corresponding scene (B) with a camera-equipped mobile phone or television. It is captured by a personal computer with a capture card, converted into a compressed video stream, and registered (uploaded) with an explanation to an information center server on the Internet.

  By using the information center server in this way, an unspecified number of other users can directly browse the corresponding scene that has already been thoroughly examined and edited by someone without searching for the content on their own. Can do.

  Recently, the number of information center servers provided with an electronic bulletin board with an image upload function is increasing, and image files and text files can be registered in the information center server with a simpler user interface.

  However, in many cases, such registration of content to the information center server is done illegally without obtaining permission from the right holder. Infringes on the portrait rights.

  However, the information center server has many systems that can be easily registered without providing a desired authentication means that can identify the registrant, and not only corporations but also individuals with the reduction of communication network line fees. But it is now possible to operate.

  For this reason, there is a problem that it is practically impossible for the copyright holder of the content to monitor for a long period of time whether or not the rights infringement is being performed for a large number of information center servers on the Internet.

(4) Transmission bandwidth problem between the user and the information center server Even if it is possible to register and publish TV program content to the information center server by solving the copyright / portrait problem (3) And a problem of transmission bandwidth between information center servers.

  Many of the current Internet connection services for individuals use ADSL (Asymmetric Digital Subscriber Line), and the bandwidth of ASDL varies greatly depending on the line environment and location conditions. Often.

  For this reason, in order to provide services to a large number of users, the information center server performs processing so as to be within 100 Kbps to 1 Mbps by applying strong irreversible compression conversion to the original video stream.

  A video stream included in a typical MPEG-TS stream of HDTV quality in Japanese terrestrial / BS digital broadcasting has a resolution of 1920 × 1080, a field rate of 60 fields / second (30 frames / second in terms of frame), and an average bit rate of about 15 Mbps. In spite of the considerably high quality, the irreversible compression conversion significantly reduces the video quality, resulting in a low quality image or video that can barely be confirmed.

(5) The problem that there is no appropriate playlist format Corresponds to the sudden viewing desire of the user recalled by recommendation (recommendation) from a third party, does not infringe the rights holder's rights, and automatically Byte offset (or disk sector) is used as a content search method to provide only the relevant scene to the user with high image quality using a huge amount of recorded compressed video stream. It is conceivable to register a simple playlist as described above in the information center server.

  FIG. 8 shows (a) a state in which some scenes are selected from a plurality of MPEG (Moving Picture Experts Group) files recorded on a recording medium, and (b) a plurality of selected scenes arranged in a playback order. FIG. 10 is an explanatory diagram showing a state where a simple playlist using byte offset designation is generated.

  In FIG. 8A, the first MPEG file 301, the second MPEG file 302, and the third MPEG file 303 are recorded on the recording medium 300, and the byte offset from the file head of the first MPEG file 301 is recorded by the user. a first scene 301-1 between b1 and b2, a second scene 302-2 between byte offsets b3 and b4 of the second MPEG file 302, and a third scene 303- between byte offsets b5 and b6 of the third MPEG file 303. Assume that 3 is selected.

  A simple playlist as shown in FIG. 8B is generated by these selected scenes. Here, the playlist is reproduced in the order of the first scene 301-1 → the second scene 302-2 → the third scene 303-3. Is generated as follows.

  As simple playlist information, a file name, a byte offset at the start position of the selected scene, and a byte offset at the end position of the selected scene are recorded.

  By registering such a simple playlist in the information center server, the same video can be quickly shared between users without transmitting video files over the Internet between devices that have exactly the same file. can do.

  However, since the naming method of the video stream file depends on the implementation of the recording / reproducing apparatus, and it does not always completely match between the plurality of recording / reproducing apparatuses, a simple playlist as shown in FIG. It cannot be directly applied to the digital broadcast recording / reproducing apparatus to be used.

  In particular, when a user actively schedules recording of a TV program, the two-hour TV program is recorded as one video stream file, or as one video stream file for one hour, or the latter one It is completely free to expand into one video stream file for the amount of time, and as long as the file organization differs depending on the device, even if a playlist is generated by specifying a byte offset, it can only be used on its own device. .

  In addition, recent HDD recorders and VDRs include a basic editing mechanism such as CM cut. However, if a part of the video stream file is deleted by the editing mechanism, the byte offset designation will be shifted. It can only be used on the device.

(6) Problem of calculation amount and memory bandwidth In order to realize a general-purpose playlist, a unique index can be assigned and searched at least for each scene unit which is a short time section of content instead of byte offset. A content search method can be considered.

  For example, Patent Document 1 describes a technique for dividing a frame image (= uncompressed image data) into blocks, calculating a color feature amount of each block, and further forming a code string.

  With this technology, for all streams in the file system, index information that can calculate the file name and byte offset from the color feature value of each frame is generated, and a playlist including the color feature value sequence can be generated. For example, it can be converted into an arbitrary playback section by performing an index search.

  However, in order to apply the extraction of the color feature amount of the frame image to a compressed stream such as MPEG, the MPEG compression is once decoded and converted into uncompressed image data, and then the uncompressed image data is processed. Therefore, it is necessary to extract the feature amount, and a huge amount of calculation processing is required.

  In addition, such feature amount extraction requires not only a processing amount but also a high-speed bus and a high memory bandwidth for handling uncompressed image data.

  For example, when an uncompressed HDTV (resolution 1920 × 1080 pixels) is processed with 8 bits for each of RGB, the transmission band corresponds to 1.5 Gbps, and the mounting cost increases significantly.

The content search method based on the recommendation (recommended) is not a special device used by a very small part of users, but is not effective unless it is installed in a commercially available HDD recorder or VDR. Since it becomes important, it is desired that the feature amount extraction is performed before the video decoding means.
Japanese Patent No. 3340532

  As described above, there are various techniques for sharing one recorded digital broadcast scene among a plurality of users. However, each technique has its own problems and is recalled by a recommendation from a third party. To search for the compressed video stream that does not infringe the rights holder's sudden viewing needs, does not infringe the right holder's rights, and is automatically recorded, and does not decode it. It was not possible to satisfy all the requirements for providing only the relevant scene.

  Therefore, the present invention searches in a state that corresponds to a user's sudden viewing desire conceived by a recommendation from a third party, does not infringe the right holder, and does not decode the compressed video stream. Another object of the present invention is to provide a recording / reproducing apparatus and a recording / reproducing system that quickly provide only a corresponding scene to a user with high image quality.

  In order to achieve the above object, a recording / reproducing apparatus (20) of the present invention is a stream data composed of a plurality of frame data groups composed of a predetermined number of frame data which are generated from digital broadcast program data in time series. The stream data to be recorded on the recording medium and the stream data recorded on the recording medium to be reproduced, the stream data input means (201) for inputting the stream data, Signature information, which is information representing the characteristics of the frame bit string, is generated from the frame bit string constituting the predetermined frame data in each of the frame data groups of the stream data input from the stream data input means (201). , Each generated signature information, and each of these signatures Signature file generating means (210) for generating a signature file including frame data group identification information for identifying each frame data group including the frame data from which the information is generated, and input from the stream data input means (201) Stream storage means (209) for storing the stream data and the signature file generated by the signature file generation means (210), and the signature file stored in the stream storage means (209) according to an external instruction A play for generating a playlist for specifying the frame data group corresponding to the registered predetermined signature information by selecting the predetermined signature information and registering the selected predetermined signature information. List generation means (212) A playlist input / output unit (213) for outputting the playlist generated by the playlist generation unit (212) to the outside and inputting the playlist generated externally; and the playlist input / output unit The signature information identical to the signature information registered in the playlist input from (213) is extracted from the signature file, and a frame data group including the frame data from which the extracted signature information is generated is defined as the signature data. And a reproduction unit (206, 207) for identifying the stream data based on the frame data group identification information associated with the information and reproducing the identified frame data group. .

  In the recording / reproducing apparatus (20), the stream data is generated by the MPEG method, and the signature file generating means (210) includes a frame bit string of an Intra picture among the frames constituting the GOP which is the frame data group. The signature information may be generated from.

  In the recording / reproducing apparatus (20), the signature information may be a hash value generated using a message digest function.

  Further, the recording / reproducing system (2) of the present invention inputs stream data composed of a plurality of frame data groups composed of a predetermined number of frame data that are generated from digital broadcast program data and that are continuous in time series. A plurality of recording / reproducing devices (20, 21) for recording the input stream data on a recording medium and reproducing the stream data recorded on the recording medium, and a server (60) via a network (200) The recording / reproducing apparatus (20) is connected to the stream data input means (201) for inputting the stream data, and each frame of the stream data input from the stream data input means (201). This frame bit is determined from the frame bit string constituting the predetermined frame data in the data group. Signature information, which is information representing the characteristics of the sequence, and each of the generated signature information and frame data group identification information for identifying each frame data group including the frame data from which the signature information is generated. A stream for storing a signature file generating means (210) for generating a signature file including the stream data input from the stream data input means (201) and a signature file generated by the signature file generating means (210) By selecting predetermined signature information from the signature file stored in the stream storage means (209) in accordance with an instruction from the storage means (209) and the outside, and registering the selected predetermined signature information , This registered predetermined sign Playlist generation means (212) for generating a playlist for specifying the frame data group corresponding to the player information, and the playlist generation means (212) via the network (200). The play list is transmitted to the server (60), and the play list transmitted from the server (60) is received, and the play list received by the network interface (50) is registered in the play list. The same signature information as the signature information is extracted from the signature file, and the frame data group including the frame data from which the extracted signature information is generated is included in the frame data group identification information associated with the signature information. Based on the stream data And reproducing means (206, 207) for reproducing the specified frame data group, and the server (60) is connected to the recording / reproducing apparatus (20) via the network (200). The playlist to be transmitted is received and stored, and when there is a transmission request for the playlist from another recording / playback device (21) connected to the network (200), the stored playlist is stored. It is characterized by comprising playlist storage means for transmitting the list to the other recording / reproducing apparatus.

  According to the recording / reproducing apparatus and the recording / reproducing system of the present invention, it is possible to cope with a sudden viewing desire of a user conceived by a recommendation from a third party, without causing infringement of the right holder, and for compression. The video stream can be searched without being decoded, and only the corresponding scene can be quickly provided to the user with high image quality.

<< First Embodiment >>
The digital broadcast recording / playback system according to the first embodiment of the present invention is a playlist generated based on signature information between a plurality of digital broadcast recording / playback apparatuses that record a broadcast signal received from a broadcast station and generate signature information. By sharing the same video, the same video is shared.

<Configuration of Digital Broadcast Recording / Reproducing System According to First Embodiment>
The configuration of the digital broadcast recording / playback system according to the present embodiment will be described with reference to FIGS.

  FIG. 1 is a block diagram showing a configuration of a digital broadcast recording / reproducing system 1 according to the present embodiment.

  The digital broadcast recording / reproducing system 1 according to the present embodiment includes a plurality of digital broadcast recording / reproducing apparatuses 20 and 21 that receive a broadcast signal transmitted from a broadcast station 10 via a digital broadcast network 100. A display device 30 and a speaker 40 are connected to the digital broadcast recording / reproducing devices 20 and 21, respectively.

  The digital broadcast recording / reproducing apparatuses 20 and 21 include a receiving unit 201, a channel selecting unit 202, an input unit 203, a stream control unit 204, a demultiplexing unit 205, a video decoding unit 206, an audio decoding unit 207, A file I / O unit 208, a stream storage unit 209, a signature file generation unit 210, a temporary storage unit 211, a playlist generation unit 212, a playlist input / output unit 213, and a playlist reproduction unit 214. .

  The receiving unit 201 is similar to a television broadcast receiving antenna, and generates a modulated signal of MPEG-TS stream data composed of time-series continuous frame data generated from digital broadcast program data transmitted from the broadcast station 10. Receive. Here, the MPEG-TS stream is a multiplexed stream obtained by multiplexing an MPEG video stream, an MPEG audio stream, and the like in a PES (packetized elementary stream) packet unit to be described later in the MPEG system.

  The channel selection unit 202 demodulates the modulation signal received by the reception unit 201, performs predetermined signal processing such as descrambling and error correction, and outputs an MPEG-TS stream corresponding to the designated broadcast program.

  The input unit 203 obtains information transmitted from a remote control device operated by a user who uses the digital broadcast recording / reproducing device 20, or obtains information instructed by a user operation such as a button, Operation control signals are generated in various blocks within the system.

  The stream control means 204 is composed of a microcomputer programmed in advance, acquires an operation control signal from the input means 203, and selectively switches the following main operation modes.

(A) Viewing mode: The MPEG-TS stream obtained from the channel selection means 202 is output to the demultiplexing means 205.

(B) Recording mode: The MPEG-TS stream obtained from the channel selection means 202 is branched into two, one being output to the file I / O means 208 and the other being output to the demultiplexing means 205.

(C) Playback mode: An MPEG-TS stream obtained from the file I / O unit 208 described later is output to the demultiplexing unit 205.

(D) Playlist creation mode: The file I / O unit 208 is controlled to acquire a signature file (to be described later) from the stream storage unit 209 and send it to the playlist generation unit 212.

  Further, when the main operation mode of the stream control unit 204 is (c) the reproduction mode, the operation control signal from the input unit 203 has the following reproduction operation mode.

(Ii) Reproduction operation mode: A part of the MPEG-TS stream recorded in the stream storage unit 209 described later is output to the demultiplexing unit 205 via the file I / O unit 208.

(B) Stop operation mode: No output.

(Ha) Playlist playback mode: Accepts the sequential input of the MPEG-TS stream file name and seek playback time information PTS from the playlist playback means 214 described later, and the corresponding MPEG-TS via the file I / O means 208. The PES packet having the reproduction time information PTS closest to the seek reproduction time information PTS in the stream is sought, and the MPEG-TS stream from that position is sequentially output to the demultiplexing means 205.

  Further, (b) when shifting to the recording mode, a file name as a key when the MPEG-TS stream is saved is generated as identification information using the date information when recording is started, and the file I / Output to the O unit 208.

  For example, when the date information “September 24, 2004, 22:23:55” shifts to the recording mode, the file name “200409242223355.mpg” is generated and output to the file I / O unit 208.

  The demultiplexing means 205 analyzes multiplexing of the acquired MPEG-TS stream and separates it into an MPEG video stream and an MPEG audio stream.

  The video decoding means 206 decodes the MPEG stream and generates a video signal.

  The audio decoding means 207 decodes the MPEG audio stream and generates an audio signal.

  The file I / O unit 208 is similar to a file system implemented in an OS (operation system) or the like, and classifies each piece of information to be read and written in file units. In addition, a part of one file is designated and read / written.

  The stream storage means 209 is a disk device that can record or read the MPEG-TS stream in real time following the bit rate of the MPEG-TS stream.

  This can be applied to a D-VHS drive, a hard disk drive, a DVD drive, or a Blu-ray drive.

  The stream storage unit 209 is a stream storage unit that stores a stream generated from content accompanied by time series. Specifically, an MPEG-TS stream and a signature file associated with the MPEG-TS stream are stored.

  When the main operation mode is the (B) recording mode, the signature file generation unit 210 generates a signature file simultaneously with the recording and stores it in the stream storage unit 209.

  The signature file here is a file in which a set of signature information and reproduction time information PTS is arranged in time series of the original MPEG-TS stream.

  An example of the data structure of the signature file is shown in FIG.

  In the signature file of FIG. 2, n pieces of signature information (1) to (n) and reproduction time information PTS (1) to (n) are arranged in accordance with the reproduction order.

  An MPEG video stream multiplexed with an MPEG-TS stream has a PES (packetized elementary stream) packet structure.

  The PES packet includes reproduction time information PTS in order to realize reproduction time synchronization between a plurality of streams multiplexed in the MPEG-TS stream, for example, MPEG streams such as video and audio.

  The signature file generation unit 210 receives the MPEG video stream from the demultiplexing unit 205, analyzes the frame structure of the MPEG video stream, expresses the characteristics of the frame bit sequence in a frame unit from a part of the frame bit sequence and shorter than the frame bit sequence. Generating signature information.

  The MPEG video stream has a hierarchical structure according to the MPEG grammar, and is divided into a sequence layer, a GOP (group of pictures) layer, a picture layer, a slice layer, an MB (macroblock) layer, and a block layer. The file generation unit 210 converts at least the picture layer and below of the MPEG video stream into signature information by a predetermined analysis algorithm.

  The signature information is generally called a hash value or fingerprint information (fingerprint), and is characterized in that the same signature information is generated from the same input bit string.

  Since the signature information is an output bit string that is sufficiently shorter than the input bit string, it is suitable as an index for quickly collating two or more data.

  However, due to the asymmetry of the input bit string length and the output bit string length (which is obvious because the input bit string length is larger than the output bit string length), it is not guaranteed that the original input bit strings are completely the same even if the signature information matches. .

  A conversion function that generates signature information having the above characteristics is generally called a message digest function (or hash function). An example of such a conversion function is the MD5 function disclosed in RFC (Request for Comment) 1321 “MD5 Message Digest Algorithm”. The MD5 function can take an input bit string having an arbitrary length and obtain an output bit string having a fixed length.

  The output bit string length R of the message digest function is generally R = 128 to 160 bits. Here, the MD5 function that is most widely used among the message digest functions is listed, but other message digest functions may be used as long as they have similar characteristics.

  Further, the signature file generation unit 210 includes information for identifying the MPEG-TS stream data of the signature information generation source using the date information on which the recording is started when the main operation mode shifts to the (b) recording mode. A signature file name is generated and output to the file I / O unit 208. For example, when the recording mode is changed to date information “September 24, 2004, 22:23:55”, the signature file name “200409242222355.mpg.sig” is generated. Using this file name as a key, the signature file is saved.

  Further, the signature file generating unit 210 acquires the reproduction time information PTS of the PES packet of the MPEG video stream currently demultiplexed from the demultiplexing unit 205 when the main operation mode shifts to the (b) recording mode, The file I / O unit 208 is controlled so that the signature information and the reproduction time information PTS are written to the signature file in a time-series order as a set at the timing when the signature information is generated.

  The temporary storage unit 211 is a cache memory used by the signature file generation unit 210 for temporarily storing an input bit string.

  When the main operation mode is (d) playlist creation mode, the playlist generation unit 212 extracts a signature information sequence corresponding to the playback section designated by the user using the input unit 203 from the signature file, and obtains playback target data. A playlist for identification is generated and written to a storage medium 213-1 of a playlist input / output means 213 described later.

  At this time, a plurality of playback sections may be designated by a GUI (graphical user interface) based on the thumbnail display of each video chapter as described in the example of Patent Document 2 described above. .

  The playlist input / output means 213 is loaded with a small-capacity removable storage medium 213-1 similar to a memory card.

  The user removes the storage medium 213-1 from the playlist input / output means 213, attaches it to another digital broadcast recording / reproduction device, or attaches it to a communication device (to be described later) such as a cellular phone, etc. To a digital broadcast recording / reproducing apparatus.

  In this embodiment, the playlist input / output means 213 is implemented by using the recording medium 213-1 such as a replaceable memory card, which is the simplest explanation, but without using the recording medium 213-1. The playlist may be transmitted / received to / from another digital broadcast recording / reproducing apparatus via the Internet or a mobile phone network. Further, a GUI (graphical user interface) similar to electronic mail software or Web browser software for that purpose may be provided in the playlist input / output means 213, or an infrared communication function with a mobile phone.

  When the main operation mode is the (C) playback mode and the playback operation mode is the (HA) playlist playback mode, the playlist playback means 214 reads the signature information from the storage medium 213-1 of the playlist input / output means 213. A column is acquired and sequentially sent to the stream control unit 204.

  The display device 30 may be a CRT display, a liquid crystal display, or the like that presents a video signal to the user.

  The speaker 40 is a device similar to a speaker or the like that presents an audio signal to the user.

  The digital broadcast network 100 is a network that connects a broadcast station 10 and a broadcast receivable area covered by the broadcast station 10.

<Operation of Digital Broadcast Recording / Reproducing System According to First Embodiment>
Next, operations of the recording process, the playlist generation process, and the playlist reproduction process in the digital broadcast recording / reproduction system 1 according to the present embodiment will be described.

[Recording process]
First, when a recording instruction is input from the input unit 203 by the user operating the remote control device, the main operation mode is switched to the recording mode by the stream control unit 204.

  When the stream control unit 204 switches to the recording mode, the MPEG-TS stream of the broadcast program of the channel selected based on the recording instruction input by the user from among the demodulated signals received by the receiving unit 201 is demodulated. Is extracted by the channel selection means 202.

  The MPEG-TS stream extracted by the channel selection unit 202 is acquired by the stream control unit 204 and branched into two. One is output to the file I / O unit 208 and the other is output to the demultiplexing unit 205.

  The MPEG-TS stream output from the stream control unit 204 to the file I / O unit 208 is stored in the stream storage unit 209 by the file I / O unit 208 following the bit rate of the MPEG-TS stream in units of files. Thus, the recording process is performed.

  The MPEG-TS stream output from the stream control unit 204 to the demultiplexing unit 205 is analyzed by the demultiplexing unit 205 to be separated into an MPEG video stream and an MPEG audio stream. 40.

  The MPEG video stream separated by the demultiplexing unit 205 is also sent to the signature file generation unit 210, and the signature file generation unit 210 performs a signature file generation process based on the MPEG video stream.

  The operation of the signature file generation process in the signature file generation unit 210 will be described with reference to the flowchart of FIG.

  When the MPEG video stream is acquired by the signature file generation unit 210, the frame structure of the MPEG video stream is analyzed, and it is monitored whether various stream headers are detected (picture header detection step S1). This algorithm is generally called an MPEG video header analyzer (MPEG video parser). Although the function is included in the MPEG video decoder, it does not handle uncompressed video data, so the amount of calculation is much smaller than the whole decoder.

  In the picture header detection step S1, No is determined until a picture header associated with each picture that is an MPEG image unit is detected, and when it is detected, Yes, the process proceeds to step S2.

  When the picture header is detected in step S1, the picture type is acquired from the picture header, and it is determined whether or not it is an Intra frame (reference frame) (picture type branching step S2).

  In step S2, if it is not determined from the picture header that the picture type is an intra picture (“NO” in S2), the process returns to step S1, and if it is determined that the picture type is an intra picture (“YES” in S2), this stream Intra picture data after the header is sequentially stored in the temporary storage unit 211 in the temporary storage step S3 until any of the next stream header, sequence header, picture header, or GOP header is detected (S3).

  When any of the next stream header, sequence header, picture header, or GOP header is detected in the temporary storage end detection step S4 (“YES” in S4), the intra picture data stored in the temporary storage means 211 is used. A hash value is generated as signature information using the message digest function (signature information generation step S5).

  Here, since an MPEG video stream obtained from MPEG-TS delivered by a broadcast wave is generated by encoding (encoding) a video material by a video encoder in a broadcast station, the same broadcast program can be converted into a different digital Since the same MPEG video stream can be obtained even when received by the broadcast recording / reproducing apparatus, the Intra picture is the same, and the signature information has the same value.

  An Intra picture is a reference frame in the MPEG compression system, and is suitable for generating signature information that can express the characteristics of video data.

  The generated signature information is combined with the playback time information PTS of the Intra picture acquired from the demultiplexing unit 205 to generate a signature file, and the file I / O with the MPEG-TS file name acquired from the stream control unit 204 It is output to the means 208 (signature file writing step S6).

  The processes in steps S1 to S6 are repeated until the end of the MPEG video stream (“NO” in input data end detection step S7). When the end of the MPEG video stream is reached (“YES” in S7), the signature file generation process is performed. Is terminated.

  As a result, in the above signature file generation algorithm, each time an Intra (reference frame) of an MPEG video stream included in an MPEG-TS stream is found, signature information is generated from an input bit string after the picture header. The

  The frame set structure of an MPEG video stream is a group of approximately 15 frames called GOP (Group of Pictures), and each GOP includes at least one Intra (reference frame). That is, when the frame rate is 30 frames / second, one signature information is a hash value indicating one GOP corresponding to a reproduction time of 0.5 seconds. This can be a suitable index for scene search of huge continuous stream data. Regardless of how the stream file organization changes, it is possible to start at least 0.5 seconds.

  The signature file acquired by the file I / O unit 208 is stored in the stream storage unit 209 together with the MPEG-TS stream.

  The MPEG-TS stream and the signature file stored in the stream storage unit 209 are associated with each other by a simple file name naming rule.

  According to the naming convention already described, for example, the stream control unit 204 gives the MPEG-TS stream a file name “200409242222355.mpg”, and the signature file generation unit 210 gives the signature file name “200409242223355.mpg.sig”. Therefore, they are different only in the extension “.sig” at the end, and can be easily associated by simple character string processing.

[Playlist creation process]
Next, the operation of playlist generation processing for generating a playlist of a recorded broadcast program will be described.

  First, when a playlist creation instruction is input from the input unit 203 by operating the remote control device by the user, the playlist creation unit 212 obtains the playlist creation instruction and the stream control unit 204 The operation mode is switched to the playlist creation mode.

  The operation of the playlist generation process in the playlist generation unit 212 will be described with reference to the flowchart of FIG.

  When a playlist creation instruction is acquired by the playlist generation means 212, the storage medium 213-1 of the playlist input / output means 213 is initialized, and a row variable Bs for substituting the playback scene start position for setting as a playlist. The value of the row variable Be for substituting the playback scene end position is initialized (playlist initialization step S11).

  When the stream control unit 204 switches to the playlist generation mode, the signature file of the broadcast program to be created as a playlist is generated based on the playlist generation instruction input by the user in the file I / O unit 208. 209 and sent to the playlist generating means 212.

  When a signature file of a broadcast program for which a playlist is to be created is selected in the playlist generation means 212 (signature file selection step S12), IN is the start position of the scene set in the playlist by the operation of the input means 203 by the user. A point is searched in units of lines of the signature file, and a variable indicating a line selected as a result of the search is substituted into a line variable Bs (IN point selection step S13).

  Next, the OUT point that is the end position of the scene set in the playlist by the operation of the input unit 203 by the user is searched for each line of the signature file, and the variable indicating the line selected as a result of the search is stored in the line variable Be. Substituted (OUT point selection step S14).

  The IN point and OUT point of the scene set in this playlist are searched by an interactive operation using the operation of the input means 203 by the user.

  Next, it is determined whether or not the substituted row variable Bs ≦ row variable Be is satisfied (registration determination step S15). When the determination result is satisfied (“YES” in S15), the process proceeds to step S16. ("NO" in S15) The process returns to step S13 without being set as a playlist.

  When it is determined in the registration determination step S15 that the row variable Bs ≦ the row variable Be is satisfied, the signature information is extracted from each row from the row variable Bs to the row variable Be, set as a playlist, and playlist input / output means It is registered by being stored in 213 (registration step S16).

  In other words, the video from the row variable Bs to the row variable Be is designated as one scene, and the signature information is extracted.

  The processes in steps S13 to S16 are repeated until the user inputs an instruction to end the playlist generation process from the input unit 203 ("NO" in end determination step S17). When it is input (“YES” in S17), the process is terminated.

  The structure of the playlist generated by this playlist generation process will be described in detail with reference to FIG.

  In FIG. 5A, signature files A, B, and C are stored in the stream storage unit 209 in advance, and the signature file A includes six pieces of signature information (11) to (16) and reproduction time information PTS ( 11) to (16) correspond to each other in line L (11) to (16) in the file according to the reproduction order, and signature file B reproduces with six pieces of signature information (21) to (26). The time information PTS (21) to (26) correspond to each other and are arranged in line L (21) to (26) in the file according to the reproduction order, and the signature file A has six pieces of signature information (31) to (31) ( 36) and reproduction time information PTS (31) to (36) correspond to each other and are arranged in line L (31) to (36) in the file according to the reproduction order.

  From these signature files, the signature file B is first selected by the user's operation, and the line (25) is substituted into the line variable Bs as the IN point for setting the playlist, and the line (26) as the OUT point. Is substituted into the row variable Be, and at this time, the row variable Bs ≦ row variable Be is satisfied, so the signature information (25) and (26), which is the signature information of the scene indicated by this row variable, is the first scene of the playlist. be registered.

  Next, the signature file A is selected by the user's operation, and the line (11) is substituted into the row variable Bs as the IN point, and the line (12) is substituted into the row variable Be as the OUT point. At this time, the row variable Bs Since the row variable Be is satisfied, the signature information (11) and (12), which is the signature information of the scene indicated by the row variable, is registered as the second scene of the playlist.

  Further, the signature file C is selected by the user's operation, and the line (31) is assigned to the line variable Bs as the IN point, and the line (32) is assigned to the line variable Be as the OUT point. At this time, the line variable Bs ≦ Since the row variable Be is established, the signature information (31) and (32), which is the signature information of the scene indicated by the row variable, is registered as the third scene of the playlist.

  The play list registered by these processes is shown in FIG. The playlist is configured in accordance with the playback order specified by the user. Here, the playlist is configured to be played in the order of the first scene of the signature file B → the second scene of the signature file A → the third scene of the signature file C. Yes.

  In the present embodiment, the procedure for interactively editing the signature file directly has been described. However, as described above, the MPEG-TS stream file and the signature file are associated with each other according to the file naming rule, and each line of the signature file. Since the corresponding scene can be easily sought by the reproduction time information PTS included in the video, the user can select the actual video while confirming the reproduction in step S13 where the IN point is selected and step S14 where the OUT point is selected. You may do it.

  Moreover, you may use the interactive play list preparation function using GUI as described in the Example of patent document 2 mentioned above.

[Playlist playback process]
Next, an operation of playlist reproduction processing when reproduction is performed using a playlist generated by another digital broadcast recording / reproducing apparatus 21 will be described.

  First, when a playlist playback instruction is input from the input unit 203 by operating the remote control device by the user, the playlist playback unit 214 acquires the playlist playback instruction and the stream control unit 204 The operation mode is switched to the playlist playback mode.

  The operation of the playlist reproduction process in the playlist reproduction unit 214 will be described with reference to the flowchart of FIG.

  When the playlist playback instruction is acquired by the playlist playback means 214, the playlist generated and recorded by the other digital broadcast recording / playback apparatus 21 is read from the storage medium 213-1 attached to the playlist input / output means 213. The total row number constant N indicating the total number of signature information in the playlist is acquired, and the row variable Bp, which is a row variable indicating the signature information column in the playlist, is set to “1”. The playlist reproduction means 214 is initialized (reproduction initialization step S21).

  Next, it is determined whether or not the acquired row variable Bp is smaller than the total number of rows N (signature information acquisition determination step S22).

  When it is determined that the row variable Bp is smaller than the total number of rows N (“YES” in S22), one piece of signature information indicated by the row variable Bp is extracted and the signature information indicating the signature information to be searched. The variable Sig is set to 1 and the row variable Bp is incremented by 1, and the searched signature file name list variable FLIST indicating the signature file already searched from the stream storage unit 209 and the signature file indicating the signature file to be searched are included. Both the name variable FN and the seek reproduction time information variable Pts indicating the reproduction time information PTS corresponding to the signature information selected by the search are set to a null value (φ) (search start step S23).

  When it is determined that the row variable Bp is larger than the total number of rows N (“NO” in S22), the process is terminated.

  Next, one signature file that is not registered in the searched signature file name list variable FLIST is selected from the signature files stored in the stream storage unit 209, and this signature file name is set in the signature file name variable FN. Further, the signature file name is added to the searched signature file name list variable FLIST (signature file finding step S24).

  Next, it is determined whether or not the signature file name variable FN is a null value (φ). If the signature file name variable FN is a null value (φ), the process returns to step S22. The process moves to step S26 (file determination step S25).

  Next, the signature file indicated by the signature file name variable FN is searched using the signature information variable Sig as a key, and the playback time information PTS paired with the matched signature information is set in the seek playback time information variable Pts. (Signature search step S26).

  If it is not found even after searching to the end of the signature file, a null value (φ) is set in the seek reproduction time information variable Pts.

  Next, it is determined whether or not the seek reproduction time information variable Pts is a null value (φ). If the seek reproduction time information variable Pts is a null value (φ) (“NO” in S27), the process returns to step S24, and seek is performed. If the reproduction time information variable Pts is not a null value (φ) (“YES” in S27), the process moves to step S28 (reproduction determination step S27).

  Next, the MPEG-TS stream file name associated with the signature file name variable FN and the seek reproduction time information variable Pts are written to the stream control means 204, and the corresponding reproduction in the corresponding MPEG-TS stream file is performed. A reproduction instruction from the time is sent to the stream control means 204 (reproduction step S28).

  Based on the playback instruction sent to the stream control means 204, the file I / O means 208 reads the MPEG-TG stream from the corresponding location from the stream storage means 209, and from the demultiplexing means 205 to the video decoding means 206 and It is reproduced by being output to the display device 30 and the speaker 40 via the audio decoding means 207.

  The operation flow of the playlist reproduction unit 214 has been described above. In this operation flow, the MPEG-TS stream file in the stream storage unit 209 is searched for in GOP units from the signature information sequence included in the playlist, and is sequentially played back.

  Since the reproduction time information PTS is a 33-bit time stamp that increases linearly along the time series, it is equivalent to the reproduction start / end position by searching the MPEG-TS stream file with the designated reproduction time information PTS. The byte offset to be performed can be easily obtained.

  For this reason, even if a part of the MPEG-TS stream file is truncated by editing, a correct byte offset can be obtained each time, which is preferable as a method for starting a scene.

  By the way, in the data structure of the playlist in the present embodiment, there is a possibility that a scene different from the intention of the playlist creator is reproduced by the playlist reproducing means 214.

  The first cause arises from the asymmetry of the input bit string length and the output bit string length of the message digest function, and the same signature information may be generated from different scenes.

  However, the name space of the 160-bit signature information is 2 to the 160th power, while the signature information managed by one HDD recorder and VDR is at most 2 to the 23rd power (MPEG-TS stream was recorded for 1000 hours) Therefore, unless the message digest function has a significant collision vulnerability, it may be regarded as not colliding.

  The second cause is that, due to the algorithm of the playlist generating means 212, only the Intra (reference frame) has the same code between the two GOPs, and the pictures in the subsequent 14 frames may be different. However, in this case as well, the probability of a collision is extremely low, considering the implementation of equipment on the broadcast transmission side.

  This is an MPEG video stream obtained from an MPEG-TS stream delivered by a broadcast wave, which is generated by encoding (encoding) video material with an MPEG video encoder (not shown) in the broadcast station. At this time, depending on the internal state of the MPEG video encoder (for example, the strength setting of the pre-noise filter, the fluctuation constraint in the transmission bit rate control, the performance of the scene change algorithm for determining which image is Intra, etc.) This is because it is generated.

  In other words, if the broadcasting station, broadcasting area, and broadcasting time zone are different, it can be expected that different signature information is generated even if only Intra (reference frame) is the same.

  Theoretically, when the original image of Intra (reference frame) included in each GOP is a special uniform image that does not contain any noise component called digital white (or digital black), collision occurs with a relatively high probability.

  However, in actual broadcast materials, the original image often includes noise components and watermarks for each broadcasting station (semi-transparent image logo for preventing illegal copying). Even if Intra is digital white, there is no problem if that part happens to be selected as one scene in the playlist.

  Furthermore, a method of reducing the probability that a different scene is selected by narrowing down the search target signature file in advance using the characteristics of the playlist can be considered.

  Since the playlist in the present embodiment is created for the user to show to a third party, the playlist is composed of a series of scenes that the user wants to show (meaning) for several seconds to several minutes or more. .

  In other words, the playlist is not a set of signature information at all, but a series of several to hundreds of signature information with a high correlation, so the signature files required for playback are extremely biased. .

  For this reason, the signature file finding step S24 is configured so that the correlation degree between the automatically recorded signature file group and the playlist is calculated in advance, and the signature file having a higher correlation degree is preferentially searched. Can reduce the error rate.

Here, an evaluation function that returns FN for the signature file name, Si for 1 to n pieces of signature information in the playlist, 1 if the signature file includes the signature information, and 0 if it is not included is f. Then, the correlation degree R can be expressed by the following formula 1.

  Equation (1) is the simplest equation for calculating the degree of correlation. The higher this value, the higher the probability that the image file is likely to contain a signature file.

  When it is desired to improve the accuracy, the adjacent probability between signatures included in all signature files may be obtained, and the degree of correlation may be calculated using dynamic programming such as Bayesian estimation.

  By the way, in order to simplify the description, the playlist reproducing means 214 sequentially searches for signature files. However, it is possible to increase the speed by applying various known search algorithms.

  For example, by using binary tree search method or Bloom filter (BloomFilter = feature bit judgment method Perl Module Bloom Filter http://www.perl.com/pub/a/2004/04/08/bloom_filters.html) A possible method is to narrow down signature files that are likely to contain information.

  In addition, due to the characteristics of the playlist, the signature file in which certain signature information can be found has a high probability of including subsequent signature information, so that the acquisition of Pts can be speeded up. More specifically, only the signature file discovery step S24 is configured so that the signature file in which the signature information Si is found is remembered and the same signature file is examined first when the search for the next signature information Si + 1 is started. But we can expect faster speeds.

  The above is the details of the digital broadcast recording / reproducing apparatus in the present embodiment. In the present embodiment, the digital broadcast program has been described as the only acquisition source of the MPEG-TS stream. Of course, the MPEG stream is acquired from a video-on-demand service, DVD media, or Blu-ray media within a range that does not deviate from the MPEG standard. Thus, a signature file may be generated and automatically stored in the stream storage unit 209.

  Further, in the present embodiment, the playlist input / output means is configured to share the playlist with other digital broadcast recording / reproducing devices by using a recording medium such as an exchangeable memory card. The playlists may be shared by a plurality of digital broadcast recording / reproducing devices by performing infrared communication between the broadcast recording / reproducing devices or by transmitting / receiving playlists by e-mail or the like via a mobile phone network.

  According to the first embodiment described above, the playlist generated by the other party is searched without infringing the rights of the right holder and without decoding the compressed video stream, and only the corresponding scene is displayed to the user with high image quality. Can be provided quickly.

<< Second Embodiment >>
A digital broadcast recording / playback system according to a second embodiment of the present invention is a playlist generated based on signature information between a plurality of digital broadcast recording / playback apparatuses that record broadcast signals received from a broadcast station and generate signature information. Are shared via the information center server, thereby sharing the same video.

<Configuration of Digital Broadcast Recording / Reproducing System According to Second Embodiment>
The configuration of the digital broadcast recording / playback system according to the present embodiment will be described with reference to FIG.

  A digital broadcast recording / reproducing system 2 according to the present embodiment includes a plurality of digital broadcast recording / reproducing devices 20 and 21 that receive a broadcast signal transmitted from a broadcasting station 10 via a digital broadcasting network 100, and these digital broadcast recording / reproducing devices. The mobile terminals 50 and 51 are respectively owned by the same users A and B as those 20 and 21, and the information center server 60 is connected to the mobile terminals 50 and 51 via the mobile phone network 200.

  A display device 30 and a speaker 40 are connected to the digital broadcast recording / reproducing devices 20 and 21, respectively.

  In the present embodiment, the mobile terminals 50 and 51 function as a network interface for connecting the digital broadcast recording / reproducing apparatuses 20 and 21 to the mobile phone network 200.

  Since the configuration of the digital broadcast recording / reproducing apparatuses 20 and 21 according to the present embodiment is the same as that of the first embodiment, detailed description thereof is omitted.

  In this embodiment, the storage medium 213-1 owned by the user A used by the playlist input / output means 213 is a removable memory card 213-1A.

  The mobile terminals 50 and 51 have a memory slot for inserting a memory card and a Web browser function. By accessing the electronic bulletin board Web service via the mobile phone 200, the mobile terminals 50 and 51 play attached to the posted text. The list binary file can be acquired from the information center server 60 and written to the memory card.

  The information center server 60 provides an electronic bulletin board Web service that can be accessed through the mobile phone network 200, and registers a file posted by attaching a playlist to a text entered by a user from the keyboard of the mobile phone. Is provided.

  Today's electronic bulletin board Web service has a function of registering and distributing binary files such as photos and videos as well as text, so there is no problem in posting with a playlist attached.

<Operation of Digital Broadcast Recording / Reproducing System According to Second Embodiment>
Since the recording process and the playlist generation process in the digital broadcast recording / reproducing system 2 according to the present embodiment are the same as those in the first embodiment, detailed description thereof is omitted.

  In the present embodiment, the memory card 213-1A storing the playlist generated by the digital broadcast recording / reproducing device 20 is removed from the digital broadcast recording / reproducing device 20 by the user A and attached to the portable terminal 50. The playlist stored in the memory card 213-1A is transmitted and registered to the information center server 60 from the portable terminal 50 through the portable telephone network 200 using the electronic bulletin board Web service.

  Thereafter, the mobile terminal 51 is operated by the user B to use the electronic bulletin board Web service via the mobile telephone network 200, and the playlist registered in the information center server is downloaded to the mobile terminal 51 and owned by the user B. Stored in the memory card 213-1B.

  When the playlist is stored in the memory card 213-1B by the user B, the memory card 213-1B is inserted into the digital broadcast recording / reproducing apparatus 21 operated by the user B.

  Since the playlist reproduction process in the digital broadcast recording / reproducing apparatus 21 is the same as the playlist reproduction process in the first embodiment, detailed description thereof is omitted.

  The above is the digital broadcast recording / reproducing system 2 in the second embodiment.

  In such a digital broadcast recording / playback system, a user who accesses the information center server 60 acquires a playlist attached to a third party post, writes the playlist to a memory card, and digitally stores the memory card. By inserting it into a broadcast recording / reproducing apparatus, it is possible to quickly reproduce a scene that is being talked about from among a large number of television programs.

  For this reason, in the digital broadcast recording / playback system according to the second embodiment, it is possible to cope with the sudden viewing desire of the user conceived by a recommendation from a third party, without infringing the rights of the right holder, and to be compressed. The video stream can be searched without being decoded, and only the corresponding scene can be quickly provided to the user with high image quality.

  In the digital broadcast recording / playback system according to the present embodiment, a memory card is used as a playlist delivery means between the mobile phone and the digital broadcast recording / playback device, but both the mobile phone and the digital broadcast recording / playback device are compatible. For example, playlists may be exchanged by wireless communication means such as millimeter wave band communication or infrared communication.

  Further, a remote control means built in the mobile phone may send a control signal to the input means 203 of the digital broadcast recording / reproducing apparatus to change the main operation mode related to reproduction.

  In the present embodiment, the mobile phone and the digital broadcast recording / reproducing apparatus are illustrated as separate apparatuses, but of course, both may be housed in the same casing. For example, today's mobile phones include a built-in digital broadcast receiving function called one-segment broadcasting (registered trademark) and a small hard disk device for recording the same. Both functions with the playback apparatus can be easily realized.

  Of the blocks constituting the digital broadcast recording / reproducing apparatus 20, the receiving means 201 and the channel selecting means 202 may be replaced with input means for receiving MPEG-TS input from the outside.

  Also, a video content recording / playback that causes a computer to function as a digital broadcast recording / playback device by incorporating all or a part of the blocks constituting the digital broadcast recording / playback device 20 into a computer that can be realized by a computer and incorporating it into the computer. It is also possible to build a program.

1 is a block diagram showing a configuration of a digital broadcast recording / reproducing system according to a first embodiment of the present invention. It is explanatory drawing which shows an example of the signature file produced | generated with the digital broadcast recording / reproducing system by 1st Embodiment and 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the signature file production | generation means of the digital broadcast recording / reproducing system by 1st Embodiment and 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the play list production | generation means of the digital broadcast recording / reproducing system by 1st Embodiment and 2nd Embodiment of this invention. It is a flowchart which shows a state when a playlist is produced | generated in the digital broadcast recording / reproducing system by 1st Embodiment and 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the playlist reproduction | regeneration means of the digital broadcast recording / reproducing system by 1st Embodiment and 2nd Embodiment of this invention. It is a general view which shows the structure of the digital broadcast recording / reproducing system by 2nd Embodiment of this invention. (A) It is explanatory drawing which shows the structure of the file system in which the conventional MPEG stream was stored, and (b) the structure of the conventional playlist.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Digital broadcast recording / reproducing system 2 ... Digital broadcast recording / reproducing system 10 ... Broadcasting station 20, 21 ... Digital broadcast recording / reproducing apparatus 30 ... Display apparatus 40 ... Speaker 50, 51 ... Portable terminal 60 ... Information center server 100 ... Digital broadcasting network DESCRIPTION OF SYMBOLS 200 ... Mobile telephone network 201 ... Reception means 202 ... Channel selection means 203 ... Input means 204 ... Stream control means 205 ... Demultiplexing means 206 ... Video decoding means 207 ... Audio decoding means 208 ... File I / O means 209 ... Stream storage means 210 ... Signature file generation means 211 ... Temporary storage means 212 ... Playlist generation means 213 ... Playlist input / output means 213-1 ... Storage medium 213-1A ... Memory card 214 ... Playlist reproduction means S1 ... Picture header detection step S2 ... Picture Ip branching step S3 ... Temporary storage step S4 ... Temporary storage end detection step S5 ... Signature information generation step S6 ... Signature file writing step S7 ... Input data end detection step S11 ... Playlist initialization step S12 ... Signature file selection step S13 ... IN Point selection step S14 ... OUT point selection step S15 ... Registration determination step S16 ... Registration step S17 ... End determination step S21 ... Playback initialization step S22 ... Signature information acquisition determination step S23 ... Search start step S24 ... Signature file discovery step S25 ... File Determination step S26 ... Signature search step S27 ... Reproduction determination step S28 ... Reproduction step

Claims (4)

Input stream data composed of a plurality of frame data groups composed of a predetermined number of frame data continuous in time series generated from digital broadcast program data, and record the input stream data on a recording medium, In a recording / reproducing apparatus for reproducing stream data recorded on the recording medium,
Stream data input means for inputting the stream data;
Signature information, which is information expressing the characteristics of the frame bit string, is generated from the frame bit string that constitutes predetermined frame data in each of the frame data groups of the stream data input from the stream data input means, and this Signature file generation means for generating a signature file including each generated signature information and frame data group identification information for identifying each frame data group including the frame data from which each of the signature information is generated;
Stream storage means for storing the stream data input from the stream data input means and the signature file generated by the signature file generation means;
In accordance with an instruction from the outside, by selecting predetermined signature information from the signature file stored in the stream storage means, and registering the selected predetermined signature information, the registered predetermined signature information is registered. Playlist generating means for generating a playlist for specifying the corresponding frame data group;
While outputting the playlist generated by the playlist generation means to the outside, playlist input / output means for inputting the playlist generated externally,
The signature information identical to the signature information registered in the playlist input from the playlist input / output means is extracted from the signature file, and a frame data group including the frame data from which the extracted signature information is generated is extracted. Reproduction means for identifying the stream data based on the frame data group identification information associated with the signature information and reproducing the identified frame data group;
A recording / reproducing apparatus comprising: The stream data is generated by the MPEG method,
2. The recording / reproducing apparatus according to claim 1, wherein the signature file generating unit generates signature information from a frame bit string of an Intra picture among frames constituting a GOP that is the frame data group. The recording / reproducing apparatus according to claim 1, wherein the signature information is a hash value generated using a message digest function. Input stream data composed of a plurality of frame data groups composed of a predetermined number of frame data continuous in time series generated from digital broadcast program data, and record the input stream data on a recording medium, In a recording / reproducing system in which a plurality of recording / reproducing apparatuses that reproduce stream data recorded on the recording medium and a server are connected via a network,
The recording / reproducing apparatus comprises:
Stream data input means for inputting the stream data;
Signature information, which is information expressing the characteristics of the frame bit string, is generated from the frame bit string that constitutes predetermined frame data in each of the frame data groups of the stream data input from the stream data input means, and this Signature file generation means for generating a signature file including each generated signature information and frame data group identification information for identifying each frame data group including the frame data from which each of the signature information is generated;
Stream storage means for storing the stream data input from the stream data input means and the signature file generated by the signature file generation means;
In accordance with an instruction from the outside, by selecting predetermined signature information from the signature file stored in the stream storage means, and registering the selected predetermined signature information, the registered predetermined signature information is registered. Playlist generating means for generating a playlist for specifying the corresponding frame data group;
A network interface for transmitting the playlist generated by the playlist generation means to the server via the network and receiving the playlist transmitted from the server;
Signature information identical to the signature information registered in the playlist received by the network interface is extracted from the signature file, and a frame data group including the frame data from which the extracted signature information is generated is defined as the signature information. Based on the frame data group identification information associated with the stream data, identifying from among the stream data, and reproducing means for reproducing the identified frame data group,
With
The server
Receiving and storing the playlist transmitted from the recording / reproducing device via the network, and storing when there is a transmission request for the playlist from another recording / reproducing device connected to the network A recording / reproducing system comprising: playlist storage means for transmitting the play list being transmitted to the other recording / reproducing apparatus.

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