JP2006049988A - Digital data recording and reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital data recording and reproducing device capable of correctly reproducing a video image from a desired scene even when a random access is generated. <P>SOLUTION: The digital data recording and reproducing device is provided with: a recording and reproducing section 107 utilizing inter-frame or inter-field correlation so as to apply compression to data in the unit of a plurality of frames or fields for the compression, recording packet form data and reproducing the data; a decoder 103 for decoding data reproduced from the recording and reproducing section to reproduce video and audio; an operation section 106 for receiving user's operations; and a system control section 105 that controls the recording and reproducing section, the decoder and the operation section and records data representing at least the start point of a scene to be reproduced on the basis of an instruction from the operation section as contents management information, and the decoder 103 decodes the compression unit including the frame or the field being the start point of the reproduced scene from its head and display by the decoder 103 is performed from the frame or the field being the start point of the decoded frames or fields. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a digital data recording / reproducing technique, and more particularly to a recording / reproducing technique capable of displaying recorded digital data from a designated desired position.

  A technique for converting video and audio into digital data and reducing the data amount of the converted data by a digital data compression technique is widely used. As a representative one, a compression method called MPEG (Moving Picture Experts Group) method is known. By using such digital data compression technology, it is possible to broadcast or store high-quality video.

  Various recording / reproducing apparatuses such as a magnetic disk (HD), an optical disk, or a recording / reproducing apparatus using a semiconductor memory have appeared as recording / reproducing apparatuses for recording / reproducing such digital data. In particular, a recording / reproducing device (HDD) using a magnetic disk is suitable for recording video data because it has a large capacity and can randomly access media. In addition, it is easy to call a desired scene or perform a high-speed search, which is easy to use.

  By the way, in the MPEG system, data compression is performed using the correlation between the preceding and succeeding images (frames). In general, data compression is often performed for a group of about 15 images. This collection of data is called GOP (Group Of Pictures). Even in the case of performing random access, data can be restored from the beginning of the reproduced data by reproducing the data from the beginning of the GOP.

For example, in Patent Document 1, in order to realize such random access, when MPEG format data is recorded on a recording medium, positions where GOPs are recorded in advance are registered as a list, and random access is performed during reproduction. Is generated, control is performed so as to start playback from the GOP head position registered in the list of GOP positions, and further, an identifier for identifying video or audio data packets to be played back, It is shown that the time required for decoding after random access can be shortened by acquiring additional information from what is separately recorded as file information.
JP 2003-284002 A

  However, in the method disclosed in the above-mentioned patent document, there is a case where it cannot be reproduced from a video of a desired scene (one scene). This is because the images handled as a GOP as a group are selected and compressed regardless of the scene head. Therefore, even if playback is performed from the video of the desired scene, the video of the desired scene cannot be decoded unless the video is decoded from the head of the GOP including the scene. For this reason, the video is reproduced and displayed from a scene different from the desired scene.

  The present invention has been made in view of these problems, and a digital data recording / reproducing apparatus capable of correctly displaying images of a desired scene when random access such as scene skip or high-speed search occurs. It is to provide.

  In order to solve the above problems, the present invention employs the following means.

Data compression is performed using multiple frames or fields as a compression unit using the correlation between frames or fields, data in packet format is recorded and played back, and data played back from the recording and playback unit is decoded Content and data representing at least the start point of the scene to be played back based on an instruction from the operation unit, controlling the recording / playback unit, the decoder and the operation unit. A system control unit that records as management information, and the decoder decodes the compression unit including a frame or field that is a starting point of a scene to be reproduced from its head, and displays the decoded frame or field. The frame or field that is the starting point Do.

  Since the present invention has the above-described configuration, even when random access such as scene skip or high-speed search occurs, it is possible to correctly display from a video of a desired scene.

  Hereinafter, the best embodiment will be described with reference to the accompanying drawings. FIG. 1 is a diagram for explaining a digital data recording / reproducing apparatus according to an embodiment of the present invention. In the figure, reference numeral 101 denotes an input terminal to which digital data compressed and multiplexed in a packet format is input. A demultiplexing unit 102 demultiplexes video data, audio data, or control data packets from the multiplexed digital data. Reference numeral 103 denotes a decoder which decodes the video and audio data separated by the demultiplexing unit 102 and decodes the original video and audio signals. Reference numeral 104 denotes a decoding buffer and a display buffer, which are used by the decoder 103 for decoding processing and video display, respectively. A system control unit 105 controls the digital data recording / reproducing apparatus. Reference numeral 106 denotes an operation unit, and the user operates the operation unit to operate the digital data recording / reproducing apparatus. Reference numeral 107 denotes an HDD forming a recording / reproducing unit, which records / reproduces digital data compressed and multiplexed in a packet format. Reference numeral 108 denotes reproduction frame management means for managing video frames to be decoded and reproduced.

  FIG. 2 is a diagram for explaining data compression and decoding processing according to the MPEG method. FIG. 2 shows an example of data compression of a video signal. An I (Intra) picture that is compressed in a frame and a P (Predictive) picture that is compressed using a correlation with a previous video frame. There is a B (Bidirectionally-predictive) picture that is data-compressed using the correlation with the previous and next video frames.

  In the example shown in the figure, 11 video frames including an I picture 201 to a B picture 211 before the next I picture 212 are set as one compression unit. That is, data compression is repeated using the data composed of the 11 video frames as a compression unit. When transmitting the compression-encoded picture data as described above, the transmission order of the frame data is rearranged as shown in FIG. Thereby, the memory capacity required for the decoding process in the decoder can be reduced.

  FIG. 3 is a diagram for explaining rearrangement of the transmission order of the frame data. In the figure, 301 indicates frame data before rearrangement (frame data in time series order), and 302 indicates frame data after rearrangement.

  For example, when attention is focused on the B1 frame of the digital data 301, the data of the I1 frame and the P1 frame are necessary to decode the B1 frame. Therefore, the data of the P1 frame that is originally temporally later than the B1 frame is used. Rearranged before the B1 frame. In the digital data 302 rearranged in this way, the video frame data from I1 to B5 is defined as a collective compression unit and defined as GOP.

  Since such data compression is performed mechanically, there is no relationship between the compression unit of the video data from the I frame and the video scene. Therefore, the head of the video scene is not always the I frame. Also, the head of the scene that the user wants to watch is not necessarily the beginning of the scene created by the video producer.

  For example, when the video frame to be decoded and reproduced is a B3 picture of the digital data 302, it cannot be correctly decoded and reproduced from the data of the B3 picture. That is, the B3 picture is compressed using the correlation with the P1 and P2 pictures, the P2 picture is compressed with the correlation with the P1 picture, and the P1 picture uses the correlation with the I1 picture. The data is compressed. Therefore, in order to correctly decode the B3 picture, it is necessary to decode from the I1 picture.

  However, the video that the user desires to view is from the B3 picture, and when decoding and playback from the I1 picture are performed, the user must view from an undesired video.

  Therefore, in the present embodiment, a desired video frame is specified as follows, and playback is performed from the specified video frame.

The user operates the operation unit 106 while the video is being fast-forwarded or reproduced at a normal speed, and instructs the start point of the scene desired to be reproduced, for example. The system control unit 105 acquires information specifying the instructed video frame from the playback frame management unit 108 and records the information on the HDD 107 as one piece of video management file information. The same applies to the end point of the scene.
After reproducing the desired scene of the video after setting the desired scene in this way, the user operates the operation unit 106 to instruct the reproduction. Upon receiving the scene playback instruction, the system control unit 105 acquires information for specifying the start and end frames of the scene from the video management file recorded in the HDD 107, and plays back the digital data including the acquired start frame from the top of the GOP. Then, control is performed so that the reproduced data is output from the HDD 107 to the demultiplexing unit 102.

  The video packet separated by the demultiplexing unit 102 is decoded by the decoder 103. At this time, the decoder 103 performs decoding using the buffer 104. Decoding is performed from the I picture at the head of the GOP. The system control unit 105 instructs the playback frame management unit 108 about the start frame, and the playback frame management unit 108 controls the decoder 103 to give a playback display instruction when the video of the start frame is decoded. Receiving this reproduction display instruction, the decoder 103 moves the decoded video to the display buffer and displays the video. Further, when decoding and playback display up to the end frame, the system control unit 105 issues an instruction to stop reading data from the HDD 107 and stops decoding and playback display.

  As described above, regardless of whether the scene desired by the user is an I, P, or B picture, it can be correctly reproduced and displayed from the designated picture image. Here, when the video frame that is the head of the desired scene is a B picture following the I picture (B-2, B-1, B0, B6, B7, B8 in the example of the digital data 302 in FIG. 3), In order to correctly decode a B picture, it is necessary to decode from the GOP immediately preceding the GOP including the B picture. In such a case, as the information for reading the digital data from the HDD 107, the GOP immediately before the GOP is used as the information. To reproduce the desired scene up to the final video frame, the GOP including the end frame may be read out, decoded, and reproduced.

  FIG. 4 is a diagram illustrating an example of digital data file management. In FIG. 4, 401 is digital data that is video content recorded in the HDD 107. Reference numeral 402 denotes a configuration example of the digital data 401, which indicates digital data of a unit for managing the position (for example, address, track number / sector number, etc.) on the HDD 107 to be recorded. Reference numeral 403 denotes content management information for managing the digital data 401. The digital data 401 is managed by the content management information 403 together with the recording position for each unit for managing the recording position, and the recording unit is one or more GOP units as shown in the configuration example 402.

  By managing in this way, a video frame of a desired scene, a GOP necessary for decoding and reproducing the video frame, and a recording position for reading the GOP from the HDD 107 are managed as file information. Playback display is possible.

  Next, a video frame specifying method will be described. In the case of digital data consisting of MPEG I, P, and B pictures, PTS (Presentation Time Stamp) and DTS (Decoding Time Stamp) are added to the I and P pictures, and DTS is added to the B picture. Further, an STC (System Time Clock) serving as a system reference is reproduced by using a PCR (Program Clock Reference) separately multiplexed as reference time information.

  With this STC as a reference, the decoding time can be managed by DTS. In addition, it is possible to manage the time for reproduction and display by PTS. These are managed separately because the order of decoding processing and the display order are different as indicated by 302 in FIG. Thus, since each piece of time information is added to each picture data, this time information can be used for specifying a video frame. As another method, a number can be assigned to a GOP or a video frame in the GOP, and the video frame can be specified by the assigned number.

  FIG. 5 is a diagram for explaining processing in a case where two desired scenes are designated from video content and are reproduced continuously. The method for designating the start frame and end frame of each scene is the same as described above.

  As shown in FIG. 5, when scene 1 and scene 2 are played back / displayed continuously, playback up to the end frame of scene 1 is the same as the playback / display processing described above. After displaying the scene 1 end frame, the system control unit 105 finishes reading the GOP of the scene 1 from the HDD 107 and starts reading the GOP including the start frame of the scene 2. The read GOP data is decoded by the decoder 103 via the demultiplexing unit 102. Decoding is performed using the decoding area of the buffer 104, and the display frame area holds the video of the end frame of the scene 1 until the start frame video of the scene 2 is decoded. When the decoding of the start frame image of scene 2 is completed, the start image is moved to the display buffer and displayed. In this way, it is possible to display an undesired video from the end frame video of the scene 1 without interposing it with the start frame video of the scene 2.

  FIG. 6 is a diagram for explaining another example of file management of digital data. In FIG. 6, the same components as those in FIG. In FIG. 6, reference numeral 603 denotes content management information for managing the digital data 401. The digital data 401 is managed by the content management information 603 together with the recording position for each unit for managing the recording position, and the recording unit is one or more GOP units as shown in the configuration example 402. This content management information is different from that of FIG. 4 in that it is not managed at the start point and end point of a scene but all scenes are managed as a start point.

  FIG. 7 is a diagram illustrating an example of scene setting for video content. Scenes desired by the user are scenes 1 and 3 as in the example of FIG. 5, and scene 2 is an undesired scene. In this example, one scene is managed from the start frame of the scene to one frame before the start frame of the next scene. The scene playback operation is the same as the management method shown in FIG. 4 except that the frame immediately before the start frame of the next scene is handled as an end frame.

  As described above, according to the present embodiment, a scene desired by the user can be designated and managed in units of video frames. In reproduction, the picture data of the designated video frame can be decoded from the head of the GOP that can be correctly decoded, and the display can be performed from the designated video frame. Therefore, it is possible to display only from a desired video frame regardless of the compression format of the designated video frame. Further, even when a plurality of scenes are designated and reproduced continuously, display can be performed without displaying an undesired video.

  FIG. 8 is a diagram for explaining another embodiment of the present invention. Components identical to those in FIG. A difference from the example of FIG. 1 is that a file division management unit 809 is provided. Hereinafter, file division management by the file division management unit 809 will be described.

  The process up to the point where the user designates a desired scene (in this example, a scene desired to be divided) is the same as in the embodiment of FIG. When file division is performed, as shown in the explanation of the operation in the example of FIG. 1, in order to reproduce a video from a picture frame in the middle of a GOP, it is necessary to decode from the first picture of the GOP. Therefore, when dividing between the picture frames in the GOP, for example, the B5 picture and the P2 picture shown in 301 of FIG. 3, in both of the divided files (the front side file and the back side file after division), respectively. Up to B5 pictures and P2 pictures must be divided so that they can be correctly decoded and reproduced. For this purpose, the GOP data I1 to B5 indicated by 302 do not exist in the front file up to B5 picture (front file after division) and the back file from P2 picture (back file after division). It will not be.

  Therefore, when dividing the file, the file division management unit 809 operates the management file information so that the GOP data including the division point is included in both the front file and the rear file of the division point. Further, when any of the above files is deleted as unnecessary, the GOP data including the division point is not deleted as information included in the remaining files.

  As described above, according to the present embodiment, the scene desired by the viewer can be designated and managed in units of video frames, as in the example shown in FIG. In reproduction, picture data of a designated video frame is decoded from the GOP head that can be correctly decoded, and display can be performed from the designated video frame. Therefore, it is possible to display from a desired video frame regardless of the compression format of the designated video frame. Further, even when a plurality of scenes are designated and continuously reproduced, the reproduction can be performed without displaying an undesired video. Furthermore, in this embodiment, when the file is divided, the GOP including the division point is managed so as to be included in both files after the division (the front file and the rear file after the division). Even if the file is reproduced alone, it can be reproduced and displayed correctly as desired by the user.

  FIG. 9 is a diagram illustrating still another embodiment of the present invention. Components identical to those in the example of FIG. A difference from the example of FIG. 8 is that a file division processing unit 909 is provided instead of the file division management unit 809. Hereinafter, the file division process will be described.

  The process up to the point where the user designates a desired scene (scene for which division is desired) is the same as the example of FIG. As shown in the example of FIG. 8, in order to display from a picture frame in the middle of a GOP, it is necessary to decode from the first picture of the GOP. Therefore, when an attempt is made to divide a picture frame in the middle of a GOP, for example, a B5 picture and a P2 picture shown in 301 of FIG. 3, both of the divided files (the divided front file and rear file) In FIG. 4, the picture must be divided so that it can be correctly decoded and reproduced from the B5 picture and the P2 picture, respectively. For this purpose, the GOP data I1 to B5 indicated by 302 do not exist in the front file up to B5 picture (front file after division) and the back file from P2 picture (back file after division). It will not be.

  When dividing the file, the file division processing unit 909 performs data replication so that the GOP data including the division point is included in both the front file and the rear file of the division point, and operates the management file information. In this case, two identical data exist by duplication. Note that from the viewpoint of protecting the copyright of the content, the duplication may exist at the same time, for example, within one minute. For this reason, for example, when the length of 1 GOP is 0.5 seconds and the number of GOP copies at one division point is one, the number of divisions possible for one video content is up to 120 points.

  In addition, since the overlap length of the content that is overlapped by the division is managed even after the division, it is inherited and managed by the file management information of the divided file. This means that when the content A is divided into A1 and A2, and A1 is further divided into A11 and A12, it is inherited not only to the management files of A11 and A12 but also to the management file of A2.

  As described above, according to the present embodiment, the scene desired by the viewer can be designated and managed in units of video frames, as in the above example. In reproduction, picture data of a designated video frame can be decoded from the head of a GOP that can be correctly decoded, and reproduction / display can be displayed from the designated video frame. Therefore, only the desired video frame can be displayed regardless of the compression format of the designated video frame. Further, even when a plurality of scenes are designated and continuously reproduced, the video can be reproduced without displaying an undesired video. Furthermore, in this embodiment, when a file is divided, the GOP including the division point is managed so as to be included in both files after division (the front file and the rear file after division). Even if the file is reproduced alone, it can be reproduced and displayed correctly as desired by the user. Further, in the present embodiment, the file is divided and the GOP including the division point is duplicated and managed so as to be included in both of the divided files. Therefore, even if each is reproduced alone, the user desires It is possible to correctly reproduce and display as shown.

It is a figure explaining the digital recording / reproducing apparatus which concerns on embodiment of this invention. It is a figure explaining the data compression and decoding by MPEG system. It is a figure explaining rearrangement of the transmission order of frame data. It is a figure explaining the example of the file management of digital data. It is a figure explaining the process at the time of designating two desired scenes from video content, and reproducing it continuously. It is a figure explaining the other example of file management of digital data. It is a figure explaining the example of the scene setting of a video content. It is a figure explaining other embodiment of this invention. It is a figure explaining other embodiment of this invention.

Explanation of symbols

101 packet format digital data input terminal 102 demultiplexing unit 103 decoder 104 buffer 105 system control unit 106 operation unit 107 HDD
108 Playback frame management unit 201, 212 I picture 204, 208 P picture 202, 203, 205, 206, 207, 209, 210, 211 B picture 301 Encoded digital data 302 Digital data in which picture order is changed for transmission 809 File division management part 909 File part activity processing part

Claims (10)

A recording / playback unit for performing data compression using a plurality of frames or fields as a compression unit using the correlation of frames or fields, recording and reproducing data in a packet format, and
A decoder that decodes data played back from the recording / playback unit to play back video and audio, an operation unit that accepts user operations,
A system control unit that controls the recording / playback unit, the decoder, and the operation unit, and records data representing at least the start point of the scene to be played back based on an instruction from the operation unit as content management information,
The decoder decodes the compression unit including the frame or field that is the starting point of the scene to be reproduced from the head thereof, and displays it from the frame or field that is the starting point of the decoded frame or field. A digital data recording / reproducing apparatus. The digital data recording / reproducing apparatus according to claim 1, wherein
A digital data recording / reproducing apparatus for recording data representing an end point of a scene as content management information. The digital data recording / reproducing apparatus according to claim 1, wherein
A digital data recording / reproducing apparatus, wherein the decoder comprises a buffer memory for decoding and a buffer memory for display. The digital data recording / reproducing apparatus according to claim 3,
A digital data recording / reproducing apparatus, wherein among decoded frames or fields stored in a decoding buffer memory, decoded data after a frame or field that is a starting point is transferred to a display buffer memory. The digital data recording / reproducing apparatus according to claim 1, wherein
A digital data recording / reproducing apparatus characterized in that identification of a video frame or field is based on time information added to the video frame or field. The digital data recording / reproducing apparatus according to claim 1, wherein
A digital data recording / reproducing apparatus characterized by identifying a video frame or field by adding a number to the video frame or field and using the added number information. The digital data recording / reproducing apparatus according to claim 1, wherein
The recording / playback unit includes a file division management unit that divides the recorded data. The file division management unit divides the file based on the data representing the division point from the operation unit, and the compression unit including the division point is divided. A digital data recording / reproducing apparatus for operating management file information so as to be included in both a front file and a rear file. The digital data recording / reproducing apparatus according to claim 1, wherein
The recording / playback unit includes a file division processing unit that divides the recorded data, and the file division processing unit divides the file based on the data representing the division point from the operation unit, and the compression unit including the division point is divided. A digital data recording / reproducing apparatus for creating a file in which the compression unit data is copied so as to be included in both the front file and the rear file. The digital data recording / reproducing apparatus according to claim 8,
A digital data recording / reproducing apparatus for limiting the number of file divisions so that the product of the reproduction time and the number of file divisions of the copied compressed unit data does not exceed a predetermined value. A recording / reproducing method for recording and reproducing data in a packet format by performing data compression using a plurality of frames or fields as a compression unit using correlation between frames or fields,
Decoding the data reproduced from the recording / reproducing unit to reproduce video and audio, accepting a user operation,
Recording data representing at least a starting point of a scene to be reproduced based on an instruction from the operation unit as content management information;
The compression unit including the frame or field that is the starting point of the scene to be played back is decoded from the beginning, and the display is performed from the frame or field that is the starting point of the decoded frame or field. And a digital data recording / reproducing method.

Images