JP4006663B2 - Disc recording device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a disk recording apparatus for recording a compressed signal such as an MPEG2 transport stream (hereinafter referred to as MPEG2-TS), and more particularly, to record a video with relatively little motion output from a monitoring camera or the like. The present invention relates to a disc recording apparatus suitable for the above.
[0002]
[Prior art]
A video recording and playback device that records and plays back video signals output from a surveillance camera records video taken from a specific location over a long period of time, and how people and objects move and what is shot. Used for the purpose of knowing. The time lapse VTR is one of such recording and reproducing devices, and this VTR enables recording of a video signal for a long time by recording an analog video signal output from a monitoring camera frame by frame.
[0003]
However, since surveillance cameras usually project scenery at the shooting location, most of the video shot over a long period of time may be still images. Therefore, when video with little movement is recorded with a time lapse VTR and the tape is played back to confirm the recorded content, the same video is monitored for a long time until the change in the target video is confirmed. There is a problem of having to.
[0004]
In addition, even when the signal is played back by high-speed playback at a higher tape running speed than usual, the change is confirmed while visually observing the motion of the poor quality video, and if necessary, it is manually switched to normal playback. There is a problem in that it is necessary to confirm a long video during recording by repeating complicated operations.
[0005]
On the other hand, a recording / reproducing apparatus using a disk is difficult to record a signal for a long time due to the problem of the recording capacity of the disk, and so far has not been considered as a positive recording / reproducing apparatus for monitoring. However, with the recent development of video signal compression and coding technology, a recording device for monitoring using an optical disk, a magneto-optical disk or the like is being studied.
[0006]
[Problems to be solved by the invention]
Here, in the case where the video signal is compressed and encoded and recorded on the disk recording medium, in order to record the video signal for a long time to some extent, the degree of compression of the video signal is increased and the information of the video signal to be recorded is recorded. The amount needs to be reduced.
[0007]
However, in general, when high-compression compression coding is performed by increasing the degree of compression of the video signal, there is a problem in that sufficient image quality cannot be obtained for monitoring purposes. Therefore, the degree of compression is increased within a range in which a certain level of image quality is maintained. For example, when a video signal for 24 hours is recorded continuously for one day, the information amount of the recorded signal at this time becomes enormous. It is very difficult to record all video signals on a disc.
[0008]
As described above, it is impossible to use the disk recording apparatus as a monitoring recording apparatus simply by increasing the degree of compression of the video signal.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, a disc recording apparatus according to the present invention receives a video signal subjected to inter-frame compression, detects the presence or absence of motion for each GOP which is the minimum editing unit of the video signal, Motion discriminating means for outputting a motion discriminating signal indicating the presence / absence of motion for each GOP, address control means for generating an address signal based on the motion discriminating signal from the motion discriminating means, and address signals from the address control means In response, recording means for recording the GOP data in the video signal on a disk recording medium, and the video signal is input, and a predetermined error correction block is formed by the GOP data in the video signal and output to the recording means. comprising a formatting means, the said address control means, based on the motion determination signal from said motion determining means, the recording When GOP data with a moving stage is recorded, the address signal is updated so that the next GOP data can be recorded following the GOP with movement, and when the recording means records GOP data with no movement. The format means always stores the GOP data from the head of the error correction block without updating the address signal so that the next GOP data overwrites the motionless GOP data. Dummy data is stored in the remaining portion where the GOP data is not stored.
[0012]
Further, the disc recording apparatus according to the present invention includes:
A time code generating means for generating a time code based on the recording time information is provided, and the time code output from the time code generating means is recorded together with the GOP data having movement.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing the main part of a disk recording apparatus according to the first embodiment of the present invention. Here, a signal is input in the form of an MPEG2 transport stream (hereinafter referred to as MPEG2-TS). An example is shown. At this time, the encoder for generating the MPEG2-TS from the analog signal may be provided on the monitoring camera side, inside the disk recording device, or separately from these devices. I do not care.
[0013]
In the figure, MPEG2-TS is supplied to GOP (Group Of Picture) detection means 1, motion detection means 2, and memory 3. Here, the GOP detection means 1 detects the GOP, which is the minimum editing unit of the video signal in MPEG2-TS, based on the presence or absence of the parameter group_start_code included in the stream data, and outputs an identification signal indicating the start position of the GOP.
[0014]
The motion detection means 2 extracts motion vector information from the value of the parameter f_code inserted in units of MPEG2-TS macroblocks, and based on the identification signal input from the GOP detection means 1 in units of GOPs. A motion discrimination signal indicating the presence or absence of motion is output. At this time, the motion detection means 2 obtains an added value of f_code for each GOP in the input MPEG2-TS, and outputs a discrimination signal indicating that there is motion when the added value exceeds a predetermined value. When the predetermined value is not reached, a determination signal indicating that there is no movement is output.
[0015]
Also, the input MPEG2-TS is temporarily written in the memory 3 regardless of the presence or absence of the motion, and the stream data for several GOPs is temporarily held in the memory 3, but the data writing and Reading is performed based on write and read addresses generated by the memory address control means 4.
[0016]
The memory address control means 4 is supplied with an identification signal indicating the head position of the GOP output from the GOP detection means 1 and a motion determination signal output from the motion detection means 2, and the memory address control means 4 is input. The write address is updated so that the stream data is sequentially written in the memory 3.
[0017]
Then, the memory address control means 4 holds the head address of the GOP having motion in the stream data written in the memory 3 based on the identification signal indicating the head position of the input GOP and the motion determination signal. At the time of reading data from 3, the read address is generated with the start address of the GOP having moved as an initial value.
[0018]
Therefore, only GOP data determined to have motion by the motion detection means 2 is read from the memory 3. The data read from the memory 3 is input to the data formatting means 5 and converted into a predetermined recording format using the identification signal from the GOP detection means 1 and the motion discrimination signal from the motion detection means 2.
[0019]
Since the GOP data that has not moved is not output from the memory 3 to the data formatting means 5, the data formatting means 5 internally holds the data until the data converted into the predetermined recording format reaches a predetermined amount. In addition, when the predetermined amount is reached, the recording data is output to the data recording means 6.
[0020]
Thereafter, the data recording means 6 records the input recording data on a disk recording medium (not shown). At this time, the data recording means 6 records the data on the disk recording medium only when the recording data is inputted from the data formatting means 5, but the disk recording medium is irrespective of the presence or absence of motion in the input MPEG2-TS. Since it always rotates at a predetermined rotational speed, even when recording data is intermittently input, it can be continuously recorded on the disc.
[0021]
As described above, the disk recording apparatus according to the embodiment of the present invention selects only the moving GOP in MPEG2-TS and records it on the disk recording medium. It is possible to select and record only a moving part, and the disk recording medium can be used efficiently.
[0022]
In the above embodiment, the memory address control unit 4 is controlled to hold only the head address of the moving GOP and read only the data of the moving GOP from the memory 3. However, the present invention is not limited to this. Alternatively, the memory address control means 4 can hold the start addresses of all the GOPs, and can control the memory 3 to read the GOP that has moved and a predetermined number of GOPs before and after the GOP. By such control, it becomes possible to record a more natural image including the images before and after the moving image on the disk recording medium.
[0023]
Next, a disk recording apparatus according to a second embodiment of the present invention is described.
FIG. 2 is a block diagram showing the main part of the disk recording apparatus according to the second embodiment. The disk recording medium shown in FIG. 3 is constructed by removing the memory 3 from the disk recording apparatus shown in FIG. A part of the recordable area is used as a buffer area in place of the memory 3. Further, in the disk recording apparatus shown in FIG. 2, the GOP detection means 1 and the motion detection means 2 are the same as those shown in the disk recording apparatus shown in FIG.
[0024]
In the disc recording apparatus according to the second embodiment, the input MPEG2-TS is input to the GOP detection means 1, the motion detection means 2, and the data formatting means 5, and all of the input stream data are recorded regardless of the presence or absence of motion. The stream data is converted into a predetermined recording format by the data formatting means 5.
[0025]
Then, the recording data from the data formatting means 5 is inputted to the data recording / reproducing means 8, and the recording data is once recorded in the buffer area of the disk recording medium shown in FIG. When the motion detection means 2 determines that the GOP recorded in the buffer area of the disk recording medium is a GOP with movement, the data recording / reproducing means 8 stores the GOP data recorded in the buffer area. The address control means 7 generates an address signal so that it is reproduced and temporarily stored and then recorded again in the data recording area.
[0026]
On the other hand, when the motion detection means 2 determines that the GOP recorded in the buffer area of the disk recording medium is a GOP having no motion, the GOP data recorded in the buffer area is not reproduced and will eventually be updated. The data is overwritten by the new GOP data.
[0027]
That is, the address control means 7 generates an address signal so that the recording data is once recorded in the buffer area of the disk recording medium regardless of whether or not the input stream data is moving, and then only the moving GOP data is selected. An address signal is generated so as to be recorded in the data recording area.
[0028]
The recording data output from the data formatting means 5 to the data recording / reproducing means 8 is divided into error correction blocks having a predetermined amount of data and output with error correction codes. At this time, the data format The means 5 always stores the data of each GOP from the head of the error correction block, and stores dummy data in the remaining portion of each error correction block where the GOP data is not stored.
[0029]
In this way, the data format means 5 prevents the GOP data with motion and the GOP data without motion from being mixed in the same error correction block, so that the motion recorded in the buffer area can be prevented. Only data of a certain GOP can be selectively transferred to the data recording area in units of error correction blocks.
[0030]
At this time, a part of the recordable area on the disk recording medium is used as a buffer area, but it is not necessary to provide the buffer area on the outer periphery of the disk recording medium, and the amount of the buffer area can be determined as appropriate. It is.
[0031]
As described above, in the disk recording apparatus according to the second embodiment, since a partial area of the disk recording medium is used as a buffer area, only a moving image is installed without installing a large-scale memory in the disk recording apparatus. Can be recorded on a disk recording medium.
[0032]
Next, a disk recording apparatus according to a third embodiment of the present invention is described.
FIG. 4 is a block diagram showing the main part of the disk recording apparatus according to the third embodiment, and no memory is mounted as in the disk recording apparatus according to the second embodiment. However, there is motion by updating the address only when moving images are recorded without using a partial area of the disk recording medium as a buffer area as in the disk recording apparatus according to the second embodiment. Only video is recorded on a disk recording medium.
[0033]
The GOP detection means 1, motion detection means 2, and data formatting means 5 are the same as those of the disk recording apparatus shown in FIG. In the disc recording apparatus according to the third embodiment, all stream data is converted into a predetermined recording format by the data formatting means 5 regardless of the presence or absence of motion in the input stream data, and the data recording means is used as recording data. 9 is output.
[0034]
The data recording means 9 records the data of each GOP on the disk recording medium for each error correction block. The address control means 7 updates the address so that the data of the next GOP can be continuously recorded when it is determined by the motion detection means 2 that the GOP is moving, and it is determined that the GOP has no movement. In such a case, the address is not updated so that the already recorded GOP data is overwritten with the next GOP data.
[0035]
FIG. 5 is a flowchart showing the operation of the disk recording apparatus according to the third embodiment. The input stream data is recorded on the disk recording medium for each error correction block (F102). Based on the motion discrimination by the motion detection means 2 (F103), if there is a motion in the GOP, the recording address of the GOP to be recorded next is updated (F104), and if there is no motion in the GOP, The recording address of the GOP to be recorded is not updated (F105). Unless there is a stop command (F106), the next GOP data is recorded.
[0036]
By repeating the above operation, the GOP data without movement is always overwritten by the data of the next GOP, and only the data of the GOP with movement is recorded on the disk recording medium.
[0037]
By such an address operation, the disk recording apparatus according to the third embodiment does not need to provide a buffer area on the disk recording medium, so that all recordable areas of the disk recording medium are used as data recording areas. Can be recorded for a long time.
[0038]
When the disk recording apparatus shown above is used as a recording apparatus for monitoring, the data format means 5 adds the recording time information of the disk recording apparatus to the input stream data and records it on the disk recording medium. It is also possible to display on the screen the time of the video that moved during playback.
[0039]
When the above disk recording apparatus is used not only for monitoring but also for other purposes, a PTS (Presentation Time Stamp) inserted for each access unit of the input MPEG2-TS and recording time information of the recording apparatus By generating a time code on the basis of and recording the time code at the same time, it is possible to reproduce in real time during reproduction.
[0040]
That is, a time code generating means for generating a time code based on the recording time information is provided, and the time code output from the time code generating means is input to the data formatting means 5 so that the time code is recorded together with the GOP data at the time of recording. During playback, the GOP data recorded on the disk recording medium that has moved is played back, and the playback time of the next GOP is adjusted based on the played back time code, and recorded on the disk recording medium without movement. A still image is output during a period in which the video of the GOP that did not exist is reproduced.
[0041]
In this way, it is possible to restore the video input to the disk recording device at the time of recording by artificially generating the video during the period when there was no motion and the video was not recorded on the disk recording medium, It can be fully used for purposes other than monitoring purposes.
[0045]
According to the first aspect of the present invention, it is possible to selectively record only a moving GOP only by controlling the recording address of the GOP recorded on the disk recording medium, and it is not necessary to provide a buffer means, and the apparatus can be simplified. The GOP data is always stored from the beginning of the error correction block, and dummy data is stored in the remaining portion of each error correction block where the GOP is not stored. This can be done in units, and only GOP data with movement can be edited efficiently.
[0046]
Furthermore, according to the second aspect of the present invention, since the time code output from the time code generating means is recorded together with the data of the GOP that moves, it is possible to reproduce in real time during reproduction.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a main part of a disk recording apparatus according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing a main part of a disk recording apparatus according to a second embodiment of the present invention.
FIG. 3 is a diagram for explaining a buffer area provided on a disk recording medium;
FIG. 4 is a block diagram showing a main part of a disk recording apparatus according to a third embodiment of the present invention.
FIG. 5 is a flowchart for explaining the operation of the disk recording apparatus according to the third embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... GOP detection means 2 ... Motion detection means 3 ... Memory 4 ... Memory address control recording means 5 ... Data formatting means 6 ... Data recording means 7, 9 ... Address control means 8 ... Data recording / reproducing means

Claims (2)

Motion discriminating means for inputting a video signal subjected to inter-frame compression, detecting the presence / absence of motion for each GOP which is the minimum editing unit of the video signal, and outputting a motion discrimination signal indicating the presence / absence of motion for each GOP When,
Address control means for generating an address signal based on a motion discrimination signal from the motion discrimination means;
Recording means for recording GOP data in the video signal on a disk recording medium in response to an address signal from the address control means;
Format means for inputting the video signal, forming a predetermined error correction block from GOP data in the video signal, and outputting the block to the recording means;
The address control means can record the data of the next GOP following the GOP having the movement when the recording means has recorded the data of the GOP having movement based on the movement discrimination signal from the movement discrimination means. When the address signal is updated and the recording means records GOP data without motion, the address signal is not updated so that the next GOP data overwrites the data of the GOP without motion,
The disc recording device is characterized in that the formatting means always stores the GOP data from the head of the error correction block, and stores dummy data in the remaining portion of the error correction block where the GOP data is not stored. apparatus. A time code generating means for generating a time code based on the recording time information;
2. The disk recording apparatus according to claim 1, wherein the time code output from the time code generating means is recorded together with the GOP data having the motion.

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