JP2011024048A - Video recording and playback apparatus, and video recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video recording and playback apparatus and video recording method, capable of retroactively broadcasting video images in which an event to be broadcasted has occurred. <P>SOLUTION: This invention relates to a video recording method for recording video data, recording latest data for a fixed time in the recorded video data and continuously recording data. Inputted video data are coded and data of volume for a time shorter than a time length of the fixed time are filed as one file 141n. This file is recorded in a recorded video recording section 141 having a recording region of capacity for recording at least three or more of the files 141n. If the recording region is filled with files, the oldest created file is deleted and the next old file is recorded in the recording area. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a continuous recording process in a video recording / playback apparatus.

  There are mainly two types of techniques for broadcasting a material using a broadcasting system: live broadcasting that broadcasts a photographed material in real time, and recording broadcasting that broadcasts a previously recorded material. In the case of live broadcasting, since the shot material can be broadcast quickly, it is often used for news programs and sports broadcasts. While it is possible to broadcast the video being shot almost in real time, on the other hand, it is difficult to predict the occurrence of events or changes in situations such as relaying various events or weather such as disasters, earthquakes, tornadoes, etc. It is unsuitable for broadcasting an unexpected event. In order to reliably broadcast such a sudden event, a video in a state in which no event has occurred is broadcast for a long time, and the broadcast time is wasted. Therefore, other materials are broadcast while no event occurs, and when an event occurs, the video is switched to broadcast the event.

  However, sudden events that require broadcasting are difficult to predict, so video can only be switched after the event has started, and events that should originally be broadcast cannot be broadcast from the beginning. . In order to broadcast such an event reliably, video recording was performed in which a video was recorded before the event occurred, and the video was broadcast after the event ended. In this case, it cannot be broadcast quickly after the event occurs. For example, Patent Literature 1 discloses a technique that enables similar playback of a live broadcast scene that is broadcast during the broadcast of another broadcast that is similar to the above problem. Yes.

Japanese Unexamined Patent Publication No. 7-46438

  The technology described in Patent Document 1 broadcasts other things so that even if other things are broadcast during live broadcasting, the live broadcast scenes broadcast during that time can be continuously played back. A delay memory is provided for delaying the amount of time. However, this delay memory merely delays the broadcast time, and there is a problem that it is impossible to broadcast from an arbitrary video as far back as the material photographed at the time when a sudden event occurred.

  An object of the present invention is to provide a video recording / playback apparatus and a video recording method capable of retroactively broadcasting a video in which an event to be broadcast has occurred.

  In order to achieve the above object, the video recording / playback apparatus according to the present invention records at least data including video, records the latest data for a certain period of time, and continuously records the data. An image recording / playback device for inputting data including at least video data, encoding the data, and filing data having a capacity shorter than the predetermined length of time as a single file A recording area having a capacity for recording at least three files created by the input means, and a recorded video recording unit for recording the file, and a file being recorded among the files recorded in the recorded video recording unit Record file management data, including old file information, oldest file information, and latest file information When the management data recording unit and the recording area are filled with files, the oldest file is deleted based on the information of the oldest file created by referring to the management data recording unit. And recording control means for recording the next file in the recording area.

  In order to achieve the above object, the video recording method according to the present invention records at least data including video, records the latest data for a certain period of time, and continues to record data. A video recording method to be performed, wherein input data including video is encoded, and data having a capacity shorter than the predetermined length of time is filed as one file, and the file is at least 3 The file is recorded in a recorded video recording unit having a recording area of at least one recording capacity, and among the files recorded in the recorded video recording unit, information on the file being recorded, information on the file created the oldest And the management data recording unit that records the management data of the file including the information of the most recently created file, and the file recorded in the recorded video recording unit. When the recording area is filled with a file, the oldest file is deleted based on the information of the oldest file created by referring to the management data recording unit. The following file is recorded in the recording area.

  According to the video recording / playback apparatus and video recording method of the present invention, it is possible to retroactively broadcast a video in which an event to be broadcast has occurred.

The block diagram which showed the structure of the video recording / reproducing apparatus which concerns on one embodiment of this invention. The figure which showed the structure of the file which the video recording / reproducing apparatus which concerns on one embodiment of this invention records. The figure which showed a mode that it recorded on the recording material recording part which the video recording and reproducing apparatus which concerns on one embodiment of this invention has recorded from the recording start to the nth minute. The figure which showed a mode that it recorded in the recording material recording part which the video recording and reproducing apparatus which concerns on one embodiment of this invention has, in time series. The figure which showed the relationship between the file recorded from the recording start to the 65th minute from the recording start, and file ID in the recording material recording part which the video recording / reproducing apparatus concerning one embodiment of this invention has. The figure which showed an example of the state management table | surface which manages the state of file ID recorded on the management data recording part which the video recording / reproducing apparatus which concerns on one embodiment of this invention has. The figure which showed an example of the order table which manages the correlation of the order between file ID recorded on the management data recording part which the video recording / reproducing apparatus which concerns on one embodiment of this invention has. The flowchart explaining the flow of the recording process which the video recording / reproducing apparatus concerning one embodiment of this invention performs. The figure which showed a mode that the conventional video recording and reproducing apparatus performed continuous recording on a tape. The figure which showed a mode that the conventional video recording and reproducing apparatus recorded continuously using two recording areas alternately.

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a video recording / playback apparatus 100 showing an embodiment of the present invention.
The video recording / playback apparatus 100 includes a video input unit (input unit) 11 that receives video data including video from a camera, a recorded video recording unit 141 that records video data input from the video input unit 11, and various management data. A recording unit 14 having a management data recording unit 142 for recording the video data, a video output unit (output unit) 12 for outputting video data recorded in the recorded video recording unit 141 to the other recording device 300 or a display 400 connected to the outside, An external control interface unit 13 to which the external control terminal 500 is connected, and a control unit (recording control means) 10 that includes a CPU and controls each unit. Each unit is connected to each other by an internal bus 15.

  The video input unit 11 includes an encoder that encodes video data from the camera, and the recording unit 14 includes a random-access recording medium such as an HDD (Hard Disk Drive) or a semiconductor memory. In addition, the recorded video recording unit 141 and the management data recording unit 142 included in the recording unit 14 are configured by recording both the recorded video and various management data on one recording medium even if they are physically configured by two recording media. It may be.

  The video output unit 12 includes a decoder that decodes the video data recorded in the recording unit 14. In the present embodiment, a series of processing operations for reading out video data compressed and recorded by the video input unit 11 from the recording unit 14 and decoding it is referred to as reproduction. That is, the video output unit 12 performs a playback process and outputs the video data subjected to the playback process to the outside.

  FIG. 2 is a diagram showing a format of video data recorded as a file 141n in the recorded video recording unit 141 of the video recording / playback apparatus 100. As shown in FIG. 2, the format of the video data recorded by the video recording / playback apparatus 100 includes a video data body part d, a header part h, and a footer part f. The header portion h includes attribute information such as the length of video data, the number of frames, a time code value, and a video and audio encoding method. Also, the footer part f includes information indicating the end of data. The video data body part d is created by sequentially recording on a recording medium, and the header part h and the footer part f are determined after the recording is completed. Therefore, a file 141n in which one video data is recorded is completed after the recording is completed. The data format shown in FIG. 2 is a general format, and the data format recorded in the recorded video recording unit 141 may be configured with a more complicated structure such as MXF (Material eXchange Format). The broadcast material handled by the video recording / playback apparatus 100 is filed in this way.

  In such a video recording / reproducing apparatus 100, an example of recording a video of a natural phenomenon that occurs suddenly, for example, a natural phenomenon such as a tornado, is shown below. In order to broadcast such a natural phenomenon, like a surveillance camera, it is recorded continuously in time before the tornado occurs, and when the tornado occurs, the video data immediately before the tornado occurs is used. It is required to start broadcasting immediately.

  In the present embodiment, for example, a case where the latest video data for one hour is always required will be described. The necessary number of hours such as the latest several hours is hereinafter referred to as “necessary number of hours”. This required number of hours may be determined based on the maximum time difference from the occurrence of an event to be broadcast until the start of the broadcast of the video recording the event. Hereinafter, the recording process for recording the required number of hours and continuing the recording will be described.

  FIG. 3 is a diagram showing a recording area for recording the required number of hours and continuing the recording. In this embodiment, the required time is divided into 60 equal parts, and 60 files in which video data having a time length sufficiently shorter than the required time of 1 minute are recorded are recorded. The number is secured. Also, in order to secure the required time and continue recording, a recording area for the file being recorded is prepared in addition to the required time. That is, it is composed of 61 files, which is the total number of hours required and one file being recorded, and a recording area having a total capacity of 1 hour and 1 minute is prepared.

  A square shown in FIG. 3 indicates a file containing a video for one minute. A file in which video data is not recorded is indicated by a white square, and a file in which video data is recorded is indicated by a lower left diagonal line. The file being recorded is indicated by both white and lower left diagonal lines. The numbers from 1 to 61 in the upper part of the rectangle indicate the number of minutes from the start of recording. In the example of FIG. 3, it is the nth minute from the start of recording. In the recording area for recording 61 files, recording is completed up to the (n-1) th minute, and n-1 files are completed. Currently, it is shown that the video of the nth minute is being recorded.

  Also, when the recording time has passed and 60 minutes (1 hour) has passed since the start of recording, the 61st video is being recorded, and at this point, the latest 1 hour of video data is recorded. It will be done.

Furthermore, when 61 minutes (1 hour and 1 minute) have elapsed since the start of recording, the oldest file is deleted and the video after the 62nd minute is recorded.
FIG. 4 shows a state in which video data after the 62nd minute is recorded. In FIG. 4 (a), the 64th minute is being recorded, and when the 64th minute recording is completed, the oldest file, the 4th minute file, is deleted to record the 65th minute video data. A file for recording the video data for the 65th minute is created. This state is shown in FIG. In this way, video is continuously recorded using a recording area having a capacity of 61 minutes (1 hour and 1 minute).

  3 and 4, the capacity of one file is a capacity capable of recording video data having a time length of 1 minute, but the recording time length is not limited to 1 minute.

  Here, with reference to FIG. 5 to FIG. 7, management data necessary for controlling to record video data for a required number of hours and continue recording will be described.

  FIG. 5 shows a recording area for explaining necessary management data. FIG. 5 shows that video data for the 65th minute is being recorded, as in FIG. 4B. And the identification information of the file required in order to control 61 files was described. In the example of FIG. 5, the identification information of the file containing the 62nd minute video data is “ID1”, and the identification information of the file containing the 63rd minute video is “ID2”.

  FIG. 6 is a state management table 142 a recorded in the management data recording unit 142. Of the 61 files recorded in the recorded video recording unit 141, the state management table 142a includes information on a reproducible head file (hereinafter referred to as a start file), and a reproducible last file (hereinafter referred to as a start file). (Referred to as an end file), information on the file being recorded, and information on the file being reproduced if currently being reproduced. The state management table 142a is updated when one file is completed and a new file is created to record the next video data or when the file is deleted. It is also updated when there is a change in the file being played.

  In the example of FIG. 6, the start file that is the first file that can be played is “ID5”, and the end file that is the last file that can be played is “ID3”. Further, it is stored that the file being recorded is “ID4” and the file being reproduced is “ID6”.

  FIG. 7 is a recording order management table 142 b recorded in the management data recording unit 142. The recording order management table 142b records the information of the file recorded next to the file for each file.

  In the example of FIG. 7, it is recorded that the next file after “ID1” is “ID2”, the next file after “ID2” is “ID3”, and the subsequent files after “ID3” are also recorded in the same manner. The The recording order management table 142b is updated as a new file is created or a file is deleted.

Next, the flow of recording processing performed by the video recording / playback apparatus 100 will be described with reference to FIG.
First, when recording is started, a new recording file is created (S11). For example, when a file with the file name ID1 is created, the recording file ID managed by the state management table 142a is recorded as “ID1”. Then, the video data input from the video input unit 11 is recorded in the newly created file (S12). Thereafter, it is determined whether or not one minute has elapsed since the start of recording in the file (S13). When it is determined that one minute has not elapsed (NO in process S13), the video data recording is continued (S13). If it is determined that one minute has passed (YES in process S13), the recorded file is closed (S14). This closing process is a process for completing one file by adding a header part h and a footer part f to the video data body d.

  When the file closing process ends, the state management table 142a and the recording order management table 142b recorded in the management data recording unit 142 are updated as a preparation process for creating the next file (S15). When this preparation process is completed, the latest file can be reproduced or output to the outside. After this preparation process is completed, it is determined whether or not the cumulative time from the start of recording (the time from the start of the flowchart of FIG. 8) has exceeded 61 minutes (S16). If it is determined that the elapsed time is less than 61 minutes (NO in process S16), the process returns to process S11, a new recording file is created (S11), video data is recorded (S12), and the subsequent processes are repeated. If the elapsed time is 61 minutes or more based on the determination in step S16 (YES in step S16), the state management table 142a indicates whether or not this start file is being played in order to delete the start file that is the oldest file. (S17). If playback is not in progress (NO in process S17), the start file is deleted (S18), and the process returns to process S11 to repeat the subsequent processes.

  If it is determined in step S17 that the start file is being reproduced (YES in step S17), the process returns to step S11 without deleting the start file, and the subsequent processing is performed. In this case, since the file for recording the next video data is newly created without deleting the start file, the number of files increases by one. As an example of processing for correcting the increased number of files, the next file after the start file to be deleted may be deleted at the time of the next processing for deleting the start file. In this case, the condition is that the next file after the start file to be deleted is not being reproduced.

  In this process S17, when it is determined that the start file is being played back, the recorded file is newly created and the total number of files is temporarily increased by 1 without deleting the start file being played back. However, among the start files being played, the most recently played frame may be displayed as a still image and the start file may be deleted. Alternatively, the next file of the start file may be controlled to be reproduced, the information on the file being reproduced in the status management table 142a may be updated to the ID of the next file, and the start file may be deleted.

(Contrast with conventional example)
Here, for comparison, recording by a conventional video recording / playback apparatus will be described.
FIG. 9 shows how a conventional video recording / playback apparatus records on a recording medium using a physically circular tape. Conventionally, recording is performed in order as shown in FIG. 9A using a physically circular tape having a length capable of recording, for example, one hour of video on a recording medium. Then, as shown in FIG. 9B, when the recording time is one round, in this case one hour has elapsed, recording is performed while overwriting the tape as shown in FIG. 9C. For example, when a natural phenomenon such as a tornado is broadcast, such a natural phenomenon occurs suddenly, so the time to record normal video data without a tornado is overwhelmingly long. If an event to be broadcast does not occur, recording continues while overwriting the physically circular tape. And when a tornado occurs, after the event to be broadcast has ended, such as after the tornado disappears or moves outside the field of view of the camera, recording on the tape is stopped, and video data from the tape is stopped. Was read and broadcast.

  Thus, when recording on an annular tape, if there is a recording capacity for one round of the tape, there is no need to replace the tape and there is no gap in recording time between them, and only one tape is sufficient. This is also convenient. And there is no need to store tapes that record unnecessary video. In the above example, the latest one hour video is recorded to meet the demand for recording and broadcasting sudden events. It was. However, there is a problem that broadcasting can only be performed after an event to be broadcast such as a tornado has ended.

  FIG. 10 shows how a conventional video recording / playback apparatus records on a randomly accessible recording medium such as an HDD or a semiconductor memory instead of recording on a circular tape. In the example of FIG. 10, as in the case of the tape of FIG. 9, a recording area having a capacity for one hour is prepared so that the latest video data for one hour can be recorded. First, recording is performed in the recording area 1 (FIG. 10A), and recording is performed in the recording area 2 when the remaining capacity of the recording area 1 is exhausted (FIG. 10B). When the remaining capacity of the recording area 2 is exhausted, the file in the recording area 1 is erased (FIG. 10 (c)) and recorded in the recording area 2. By repeating this process, it is possible to record the latest video for one hour and continue recording. If the recording area 1 and the recording area 2 are an HDD or a semiconductor memory, as described above when explaining FIG. 2, the recording area 1 and the recording area 2 are composed of a video data main body portion, a header portion, and a footer portion. Since the part is determined after the recording is completed, one file in which the video data is recorded is completed after the recording is completed. Once the file is complete, it can be played.

In this way, it is possible to record video data for one hour, but to continue recording while recording the latest video data for one hour, as in the case of tape, recording is necessary. In addition to the recording area for recording the completed video for one hour, another recording area for recording is required. That is, in order to continue recording while recording the latest one hour of video, a recording area twice the capacity of the required time (in this example, one hour) is required, and the video recording / playback apparatus The hindrance to miniaturization or price reduction.
The above is a comparison with the conventional example.

  As described so far, in this embodiment, for example, the required number of hours for one hour is configured by a file for each minute, and recording capable of recording a file having a time length of one minute in addition to a recording area for the required number of hours. By preparing the area, it is possible to continuously record while recording the latest one hour of video. The capacity of the recording area necessary for such continuous recording is, for example, a capacity of 1 hour and 1 minute if the required time is 1 hour. Can be reduced. Furthermore, since the video having the required time of 1 hour is composed of 60 files, it can be played back after 1 minute has elapsed since the start of recording.

  Various effects such as reducing the required capacity in addition to the required number of times and reducing the time from the start of recording to the time when playback is possible are as follows. It becomes more remarkable by making smaller. In order to enable continuous recording using at least a recording area smaller than twice the required number of hours, at least three files with a video length shorter than the required number of hours are required. You only have to. In addition, since the capacity of one file is set to record one minute of video, management is easy.

  In addition, this invention is not limited to the above structure, A various deformation | transformation is possible. For example, in the embodiment, for simplicity of explanation, the file ID is represented by a number such as “ID1”. However, since the file ID corresponds to the file name, the file name is alphanumeric or kanji. May be. Further, the data included in the file may include not only video but also audio and other information. Furthermore, the required time and the capacity of one file are not limited to one hour and one minute, respectively. In addition, the capacity of the recorded video recording unit 141 may be larger than the capacity of the recording area obtained by adding the capacity of one file to the required number of hours. In this case, even if the recorded video recording unit 141 has a large capacity, continuous recording is performed using the capacity of the recording area. Therefore, when processing other than continuous recording is performed, the capacity can be secured. .

DESCRIPTION OF SYMBOLS 10 ... Control part, 11 ... Video input part, 12 ... Video output part, 13 ... External control interface part, 14 ... Recording part, 141 ... Recorded video recording part, 141n ... File, 142 ... Management data recording part, 142a ... State Management table, 142b ... Recording order management table, 15 ... Internal bus, 100 ... Video recording / playback device, 200 ... Camera, 300 ... Other recording device, 400 ... Display, 500 ... External control terminal, h ... Header part, d ... Data Body part, f ... Footer part.

Claims (4)

A video recording / playback device that records at least data including video, records the latest data for a certain period of time, and continues to record data.
Input means for receiving data including at least a video, encoding the data, and filing data having a capacity for a time shorter than the time length for the predetermined time as one file;
A recording area for recording at least three files created by the input means, and a recorded video recording unit for recording the files;
Of the files recorded in the recorded video recording unit, record file management data including information on the file being recorded, information on the oldest file created, and information on the latest file created A management data recording unit;
When the recording area is filled with a file, the oldest file is deleted based on the information of the oldest file created by referring to the management data recording unit, and the next file is A video recording / reproducing apparatus comprising recording control means for recording in a recording area. An output means for reading and decoding the file recorded in the recorded video recording unit and outputting the decoded data;
The management data recording unit further records information of the file being output by the output means,
The recording control unit refers to the management data recording unit, and when the file to be deleted is being output, records the next file in the recording area without deleting the file to be deleted. The video recording / reproducing apparatus according to claim 1. An output means for reading and decoding the file recorded in the recorded video recording unit and outputting the decoded data;
The management data recording unit further records information on the file being output by the output means, and information related to the recording order between the files recorded in the recorded video recording unit,
The recording control unit refers to the management data recording unit, and when the file to be deleted is being output, the output from the output unit is changed from the file being output to the next file, 2. The video recording / playback apparatus according to claim 1, wherein the file to be deleted is deleted, and the next file is recorded in the recording area. It is a video recording method that records data including at least video, records the latest fixed time of the recorded data, and continuously records data,
Encode the input data including video, and file the data with a capacity shorter than the predetermined length of time as one file,
Recording the file on a recorded video recording unit having a recording area having a capacity for recording at least three files;
Of the files recorded in the recorded video recording unit, record file management data including information on the file being recorded, information on the oldest file created, and information on the latest file created Record the management data of the file recorded in the recorded video recording unit to the management data recording unit,
When the recording area is filled with a file, the oldest file is deleted based on the information of the oldest file created by referring to the management data recording unit, and the next file is A video recording method characterized by recording in a recording area.

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