JP3487483B2 - Recording / reproducing method of moving image signal - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for compressing a moving image signal and recording / reproducing it in a storage device, and more particularly to a recording / reproducing device for a moving image signal to which time information is added,
Also, the present invention relates to reproduction of a moving image signal using time information and improvement of the reproduction method.

[0002]

2. Description of the Related Art In recent years, image processing technology, especially compression technology for image information and audio information, has made remarkable progress and is capable of transmitting high-quality moving images and audio even on a transmission line having a small capacity. became. By the way, the monitoring system
A surveillance camera is installed at a certain location, and the video of that location is played back on the monitor in real time, while it is stored in a storage medium, and the stored video is played back as needed, allowing long-term monitoring. It is a possible system. FIG. 3 shows an outline of a general monitoring system, which will be described below. This system includes a camera 1, a system stream (hereinafter referred to as SS) creation unit 2, a transmission unit 3, a storage device 4, a switching unit 5, an SS analysis unit 6, and a monitor 12.
It is composed of

The SS creating section 2 encodes and compresses a video image taken by the camera 1, a so-called video signal 1a, to obtain compressed data. Information such as a header is added to the compressed data and output as a system stream 8 as shown in FIG. The transmission unit 3 is a transmission line that takes in the system stream 8 from the sending end side and outputs the system stream 9 to the receiving end side for transmission. Storage device 4
Records the system stream 9 obtained from the transmission unit 3 in a storage medium in a format described later. This record is recorded in a file format. When reproducing, the file name information 11 is specified, and the corresponding system stream 10 accumulated by this is read and output to the switching unit 5. The switching unit 5 switches between the system stream 9 obtained from the transmission unit 3 and the system stream 10 stored in the storage medium inside the storage device 4, and transmits the system stream 9 to the SS analysis unit 6.

The switching of transmitting the system stream 9 to the SS analysis unit 6 is the switching of recording the image captured by the camera 1 in the storage device 4 while reproducing it on the monitor 12 in real time. Further, the switching of transmitting the system stream 10 to the SS analysis unit 6 is a switching of transmitting the accumulated system stream 10 to the SS analysis unit 6 and reproducing the recorded video. The above switching can be arbitrarily set from the outside by the switching signal 13. The SS analysis unit 6 separates and divides the system stream 14 obtained from the switching unit 5 into pieces of information based on information such as a header. Then, the compressed data in the separated information is decoded into decompressed image data so that the monitor 12 can monitor it. By the way, unless the system clocks of the transmitting side and the receiving side have the same frequency, the video reproduced on the monitor 12 is broken. The cause of the failure will be described later. Therefore, the transmitting side adds information regarding the time for synchronizing the receiving side system clock to the transmitting side system clock (hereinafter referred to as SCR information) to the system stream to be created and transmits it to the receiving side. The receiving side uses the SCR information in the transmitted system stream to generate a receiving side system clock having the same frequency as the transmitting side system clock.

FIG. 4 is a schematic diagram of the system stream 8 created by the SS creation unit 2. This system stream is basically formed by repeating header information, SCR information, and compressed data. Next, the monitoring system will be described with reference to FIG. 5, focusing on this SCR information. The SS creation unit 2 uses VENC2-1 and FiFo, which will be described later.
Memory 2-2, STC counter 2-3, header controller 2
-4, a latch 2-5, and a switch 2-6. V
ENC2-1, writing side of FiFo memory 2-2, S
The system clock 15 related to the video signal 1a is supplied from the system clock (CK) generator 14 to the TC counter 2-3 (a counter that generates a counter value serving as a reference of SCR information). For example, the frequency is 2
It is 7 MHz. On the read side of the FiFo memory 2-2, the header controller 2-4, the latch 2-5, and the switch 2-6,
A transmission sending clock (CK) 16 related to the transmission unit 3 is supplied.

Further, the read side of the FiFo memory 2-2, the latch 2-5 and the switch 2-6 are the header controller 2-
It operates in synchronization with the transmission / sending CK16 in response to the control signal from the control unit 4. Here, VENC is an abbreviation for Video Encoder, and VENC2-1 converts the video signal 1a into compressed data information based on the system clock 15. This compressed data information is instantaneously output in synchronization with 27 MHz, but the data rate is smaller than the capacity of the transmission unit 3 on average. Then, this compressed data information is F
The data is written into the iFo memory 2-2 at 27 MHz, read by the transmission / sending CK16, and converted into the transmission rate of the transmission unit 3. The header controller 2-4 adds the header information for SCR output by itself by the switch 2-6 and then adds the latch 2
-5 output, that is, the switch 2-6 is controlled so as to selectively add SCR information, and after adding header information for compressed data, the output of the FiFo memory 2-4 which is compressed data information, that is, The compressed data is selected and the system stream 8 is completed.

[0007] The STC counter 2-3 is a counter that operates on the system clock, and is, so to speak, a clock that the transmitting side uses as a reference. The latch 2-5 is a header controller 2-
According to the control signal from 4, the STC counter value at the corresponding time is held and this value is output as SCR information. This SCR information is added to the system stream 8 at an almost constant cycle, and the cycle is a maximum of 0.7 seconds, usually 5 seconds.
It is often about 0 ms. The system stream 8 which is the output of the SS creation unit 2 is configured by repeating an SCR header, SCR information, a compressed data header, and compressed data information (see FIG. 4), and finally, for example, 6.144.
It becomes a data group in Mbps. Since the transmission unit 3 generally uses a public line network, a usable transmission rate is designated by a transmission line. Therefore, the transmission clock to the SS creation unit 2 is supplied from the transmission unit 3. So in general,
System clock 15 and transmission clock 16 for transmission and transmission
Is in an asynchronous relationship, and when the FiFo memory 2-2 is about to underflow, the header controller 2-4 inserts padding data, which has no meaning in content, into the system stream 8 instead of the compressed data information. Increase the transmission data. Note that a padding data header is naturally added at the time of insertion.

Next, the SS analysis unit 6 on the receiving side includes a header analyzer 6-4, a FiFo memory 6-2, and an SCR extractor 6-.
6, receiving side STC counter 6-3, latch 6-5, VD
It consists of EC6-1. Here, VDEC means Video De
Abbreviation for coder. The transmission reception clock 16 ′ (frequency 6.144 MHz) is supplied to the header analyzer 6-4, the writing side of the FiFo memory 6-2, and the SCR extractor 6-6. Reading side of FiFo memory 6-2, receiving side ST
The reception side system clock 20 (frequency of 27 MHz) is supplied to the C counter 6-3 and VDEC 6-1. The header analyzer 6-4 searches the received system stream 14 for header information, and stores the information following the header information in the FiFo memory 6-2 or the SCR extractor 6-6.
Control signal to be captured by the receiver and the receiving side ST at that time
A control signal for holding the value of the C counter 6-3 in the latch 6-5 is output. VDEC6-1 is Fi
The compressed data information read from the Fo memory 6-2 is decompressed, and the original image signal is decoded and reproduced. In addition, when the compression processing is performed, the image quality is slightly deteriorated. As described above, the SS analysis unit 6 receives the image signal decoded and reproduced from the VDEC 6-1, the SCR information 17 extracted from the SCR extractor 6-6, and the receiving side STC held from the latch 6-5. The counter value output 18 is output.

Next, the VCO control section 7 for generating the receiving side system clock 20 will be described. The VCO control unit 7
It is composed of a difference detector 7-1, an amplification unit (hereinafter, AMP) 7-2, and a low pass filter (hereinafter, LPF) 7-3. The difference detector 7-1 uses the extracted SCR information 17 and the receiving side S
The TC counter value outputs 18 are compared and the analog error amount e corresponding to the difference is output. The error amount e is A
The MP7-2 and the LPF 7-3 convert the gain, offset, frequency characteristic, etc. into a control signal f adapted to the control range of the VCO 19. The VCO 19 performs an operation of increasing or decreasing the output frequency according to the voltage of the control signal f. With such a configuration, the VCO control unit 7 compares the STC counter value output 18 on the receiving side with the SCR information 17 which is the value of the SCR extractor 6-6, so that the difference between the two becomes constant. It controls the system clock 20. Here, for example, when the SCR information 17 is larger than the reception side STC counter value output 18, the VCO 19 is controlled so that the frequency of the reception side system clock 20 becomes higher.

On the contrary, when the SCR information 17 is smaller than the STC counter value output 18 on the receiving side, the VCO 19 is controlled so that the frequency of the system clock 20 on the receiving side becomes low. By repeating these operations, the receiving side STC counter 6-3 and the transmitting side STC counter 2-
3, the count operation is continued while outputting substantially the same value, and the frequencies of the reception side system clock and the transmission side system clock are the same. In other words, the receiving side also has a clock that moves at the same tempo as the reference clock of the transmitting side. This can also be used to realize a synchronous operation of video and audio when compressing and expanding them.
Here, a description will be given of a defect when the frequencies of the receiving system clock 20 and the transmitting system clock 15 do not match. For example, the receiving system clock 20
Is 27.27 MHz, the system clock 15 on the transmitting side has a frequency of 27.0 MHz, and the clock frequency on the receiving side is 1% higher. The moving image displays a predetermined number of frame images per second, and 27.0M
If 30 sheets / second at 2 Hz, 30.3 at 27.1 MHz
Sheets / second. Therefore, the SS creation unit 2 on the sending side
Although only 300 frames of images are transmitted per second,
The SS analysis unit 6 on the reception side outputs an image of 303 frames, which causes a contradiction. That is, in this case, S
The FiFo memory 6-2 that is the buffer of the S analysis unit 6 is in an underflow state and outputs erroneous data. Therefore, the image in which the erroneous compressed data information is decoded and reproduced by the VDEC 6-1 becomes abnormal. Cause

FIG. 6 shows a specific structure of the storage device 4, which will be described below. The storage device 4 includes an input control unit 4-1,
The output control unit 4-2, the file name search unit 4-3, the clock generator 4-4, and the storage medium 4-5 are included. The input control unit 4-1 obtains the system stream 9 and the transmission clock 16 obtained from the transmission unit 3, generates a write control signal 21 with the transmission clock 16 as a reference, and stores the system stream 9 in a file format in the storage medium 4 Accumulate at -5. The file name search unit 4-3 generates a corresponding search signal 24 based on the file name information 11 arbitrarily set from the outside, and selects a file having the same name from the files stored in the storage medium 4-5. Search for. And
The control signal 25 indicating the match / mismatch between the set file name and the stored file name is obtained, and the output control signal 26
Is output to the output control unit 4-2. The output control unit 4-2 is
When the coincident output control signal 26 is obtained, the corresponding system stream 10 is output in the form of outputting the searched file from the top of the file. In addition, the output control signal 2 that does not match
When 6 is obtained, the system stream is controlled not to be output. Here, the clock (CK) generator 4-4 generates a clock having the same frequency as the transmission clock 16.

Next, FIG. 7 shows an outline of the storage medium 4-5, and the reproducing method will be described. As described above, the system stream 9 is stored in the file format. For example, FILE1, FILE2, ..., FILEn, and naturally these files are system streams. Here, when FILE1 is reproduced, FILE1 which is a file to be reproduced is set in the file name information 11 and the same file name is searched from the accumulated files. Then, when retrieved, the header information (1) at the head of the FILE 1 is sequentially output in the form of SCR information (2), compressed data (3), .... That is, the reproduced images are in the order of the compressed data (3), the compressed data (6), and the compressed data (9). In addition, compressed data of FILE1
When reproducing from (6), since reproduction is performed in file units, header information (1) to compressed data (3) are FILE.
3, the following is divided from the header information (4) as FILE4, and FILE4 is reproduced. By the way, the SCR information in the system stream is information for synchronizing the receiving side system clock with the transmitting system clock and is generated based on the STC counter value as described above. There is no regulation on the initial value of the counter. That is, the SCR information starts the counting operation when the system is activated.

[0013]

In the system of the prior art, in recording a moving image signal, the moving image signal stored in the storage medium is recorded with information or moving image corresponding to the time when the shooting of the moving image is started. In order to know at what time and at what time the image was captured or recorded during playback, information such as the time corresponding to the start time was added to this moving image signal in addition to the moving image signal. It is necessary to transmit the time information corresponding to the time when the signal is photographed or recorded, which increases the amount of transmission data. Further, since the moving image signal is stored in the storage medium in file units and the key at the time of reproduction is only the file name, reproduction can be performed only in file units. Therefore, all the video in the file will be played, and in order to play from the video in the middle of the file or to play the video that is partially cut, it is necessary to divide the file or create an application that realizes it. was there. The present invention records and reproduces a moving image signal to which time information such as shooting time and recording time is added, reproduces the corresponding moving image signal by searching the time information, displays the time on a monitor, and retrieves a moving image. It is an object to be able to control the reproduction order of image signals.

[0014]

In order to achieve the above object, the present invention provides a system for compressing and recording and reproducing a digital moving image signal, wherein the moving image is added to the system stream of the compressed moving image signal. Information corresponding to a predetermined processing time of a signal (hereinafter referred to as processing time information) is periodically added and recorded on a storage medium, and at the time of reproduction, the processing time information added to the recorded system stream is recorded. The necessary processing time information is searched from the inside, and the moving image signal corresponding to the searched processing time information is reproduced together with the processing time information. Further, it is possible to control the reproduction order by searching a plurality of processing time information and reproducing the moving image signal corresponding to each searched processing time information.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a system configuration of a moving image signal recording / reproducing apparatus of the present invention, which will be described. However, the same reference numerals as those in FIG. This system includes a photographing time information setting unit 27, SS
It includes a creation unit 2, a transmission unit 3, a storage device 28, a switching unit 5, and an SS analysis unit 6. In the shooting time information setting unit 27, the initial count value of the STC counter 2-3 is set by the shooting time information 29 and the load signal 30. That is, the arbitrary photographing time information 29 is set in the STC counter 2-3, and at the same time as the photographing is started by the load signal 30, the counting is started from the photographing time information 29. This STC
SCR information is generated based on the counter value, usually 50m
It is added to the system stream 8 in the cycle of s as described above. As a result, the shooting time information is normally added to the system stream 8 in a cycle of 50 ms. When the SS analysis unit 6 obtains the transmitted system stream 14, the shooting time display data generation unit 6-7 extracts the shooting time information from the transmission-side SCR information 17 extracted from the system stream 14 to obtain the shooting time. Convert to display data. Then, the shooting time is displayed together with the image on the monitor 12 (FIG. 3) in the subsequent stage.
The operations of the transmission unit 3, the switching unit 5, and the VCO control unit 7 are the same as in FIG.

Now, the added photographing time information will be described more concretely. For example, when shooting is started at 8:00 am, the STC counter value is operated from "0" at the same time. Then, when searching / reproducing a moving image, if the predetermined SCR information of the system stream added in a cycle of 50 ms is detected, the S
It is possible to obtain the elapsed time up to the portion where the CR information is added. That is, for example, if the detected SCR information is "FFFFFFFF" in hexadecimal, the STC counter value and ST that are the basis of this SCR information
The elapsed time T from the start of shooting to the part to which the SCR information is added can be calculated from the transmission clock that is the reference for the C count operation. Elapsed time T = 37 ns × “FFFFFFFF” (1) (37 ns is one cycle of the clock frequency of 27 MHz) Here, when the above formula (1) is calculated, 159 s (2/3 minutes)
9 seconds). Therefore, by retrieving the SCR information from the system stream and reproducing the SCR information from the system stream, the video imaged at 8: 2: 39 am can be reproduced.

Next, FIG. 2 shows a detailed structure of the storage device 28, and its operation will be described. The storage device 28 includes an input control unit 28-1, an output control unit 28-2, an SCR information search unit 28-3, a file name search unit 28-4, a clock generator 28-5, a storage medium 28-6, and a control device. 28-7. The input control unit 28-1 obtains the system stream 9 and the transmission clock 16 obtained from the transmission unit 3, generates the write control signal 31 based on the transmission clock 16, and stores the system stream 9 in the storage medium 28-6. Accumulate in the format. The file name search unit 28-4 is
A corresponding search signal 32 is generated based on the file name information 11 which can be arbitrarily set by the control device 28-7, and the set file name is searched from the files stored in the storage medium 28-6. Then, the control signal 37 indicating the match / mismatch between the set file name and the stored file name is obtained, and the control signal 33 corresponding to the SCR information search unit 28-3 is output. SCR information retrieval unit 28-
No. 3 generates the SCR search signal 34 when the control signal 33 indicating that the file names match is generated, and is the same as the SCR designation information 17 'that can be arbitrarily set by the control device 28-7 from the accumulated files. Retrieve SCR information. The control signal 35 which is the search result is obtained, and the output control signal 3
6 is output to the output control unit 28-2.

When the output control section 28-2 obtains the output control signal 36 indicating that the SCR information corresponding to the set file name is retrieved, the output control section 28-2 outputs the retrieved file from the corresponding SCR information of this file. The system stream 10 is output. Also, the set file and S
When the output control signal 36 indicating that the CR information could not be retrieved is obtained, the system stream is controlled not to be output. Here, the clock (CK) generator 28-5 generates a clock having the same frequency as the transmission clock 16.

Next, the storage medium 28-6 shown in FIG.
A method of searching for and reproducing a desired moving image signal will be described based on the internal structure of the files stored in. When a moving image signal is recorded, the F
ILE1, FILE2, ..., FILEn, but the difference from the prior art is that the SCR information is associated with the shooting time information. By the way, in sports news, etc., it is often the case that explanations are made while playing back images in places rather than playing them back continuously. This will be described below by taking an image as an example. First, the shooting is started at the same time as the start of the marathon, and the system stream 9 is stored in the storage medium 28-6. here,
When the data is stored in the storage medium 28-6, for example, the system stream 9 obtained by shooting the first group, which is the leading group of the marathon, from the start to the finish is FILE.
Similarly, the system stream 9 in which the second group is photographed from the start to the finish is set to FILE2. In addition, SCR information (S11) of FILE1 and FILE2
SCR information (S20) is 15 after the marathon started
Minutes later, indicating the SCR information of FILE1 (S14) and FILE
The SCR information (S23) of 2 indicates after 30 minutes, and the SCR information of FILE1 (S17) and the SCR information of FILE2 (S26) are 45 minutes.
Suppose it indicates minutes later.

In such an accumulation situation, the video of the first group 15 minutes after the start of the marathon is played for 10 seconds, then the video of the second group 15 minutes after is played for 5 seconds, and then A case will be described in which the video of 30 minutes after the first group is reproduced for 5 seconds. First, in the controller 28-7, the FI which is the system stream of the first group.
LE1 is searched, and if it is searched, SCR information (S11) 15 minutes after starting from this is searched. Then, when the SCR information (S11) is retrieved, the compressed data (S12) following the SCR information (S11) for 10 seconds.
To play. Next, FILE2 which is the system stream of the second group is searched, and when this is searched, the SCR information (S20) 15 minutes after the start is searched. When the SCR information (S20) is retrieved, the compressed data (S2) that follows the SCR information (S20) is retrieved for 5 seconds.
Play 1). And again, FILE1 which is the system stream of the first group is searched, and if it is searched, SCR information (S14) 30 minutes after the start in this is searched.
To search. Then, when the SCR information (S14) is retrieved, the compressed data (S15) following the SCR information (S14) is reproduced for 5 seconds. By controlling the control device 28-7 as described above, the compressed data (S12), the compressed data (S21), and the compressed data (S15) can be reproduced in this order. As described above, the initial value of the STC counter value that is the basis of the SCR information is made to correspond to the shooting start time, and the system stream including the SCR information is recorded in the storage medium, so that the storage medium can be recorded in the storage medium during reproduction. Since it is possible to search for each SCR information corresponding to the shooting time in the accumulated system stream, the images from the desired shooting time in the moving image signal can be reproduced in a desired order, and the desired images can be reproduced. The moving image can be reproduced and displayed together with the shooting time.

[0021]

As described above, according to the present invention, since the time information is added to the moving image signal, an image at an arbitrary time can be searched and reproduced immediately with this time information. It is effective to apply the method to a surveillance system or the like that requires quick retrieval and reproduction of an image at a required time from long-term surveillance images. Further, since it is possible to control the reproduction order of various images, it is possible to improve the efficiency of image editing / reproduction work in television broadcasting such as sports news.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of a moving image recording / reproducing system of the present invention.

FIG. 2 is a block diagram showing a configuration of a storage device of the present invention.

FIG. 3 is a block diagram showing an outline of a system in the related art.

FIG. 4 is a schematic diagram showing an outline of a system stream.

FIG. 5 is a block diagram showing a system configuration in a conventional technique.

FIG. 6 is a block diagram showing a configuration of a storage device according to a conventional technique.

FIG. 7 is a schematic diagram showing a state of accumulated data of a storage medium in the related art.

[Explanation of symbols]

1: Input video signal, 2: SS creation section, 2-1: VEN
C, 2-2: FiFo memory, 2-3: transmission side STC counter, 2-4: header controller, 2-6: switcher, 3:
Transmission unit, 5: switching unit, 6: SS analysis unit, 6-1: VDE
C, 6-2: FiFo memory, 6-3: STC counter on reception side, 6-4: Header analyzer, 6-6: SCR extractor, 6-7: Display data generation unit, 7: VCO control unit,
8, 9 and 10: System stream, 11: File name information, 13: Switching control signal, 14: System CK generator, 17 ': SCR designation information, 18: STC counter hold value on receiving side, 19: VCO, 20: Receive clock,
27: shooting time information setting unit, 28: storage device, 29: shooting time information, 30: load signal, 28-1, input control unit, 28-2: output control unit, 28-3: SCR information search unit, 28 -4: File name search unit, 28-5: CK generator, 28-6: Storage medium, 28-7: Control device, 3
1: write control signal, 32: file name search signal, 3
3: Control signal, 34: SCR information retrieval signal, 35: Control signal, 36: Output control signal.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04N 5/91-5/956

Claims (4)

(57) [Claims] 1. A system for compressing and recording and reproducing a digital moving image signal, wherein the compressed moving image signal is
Received, added periodically in the containing system stream
Side system clock is synchronized with the sender system clock.
The SCR information about the time for
When processing by setting the initial value to correspond to the predetermined processing time of
The system stream is used as the time information
At the time of recording and reproducing the data in the file, the necessary processing time information is searched from the processing time information in the recorded system stream , and the pressure corresponding to the searched processing time information is searched.
From the point where the compressed video signal is recorded,
A method of recording and reproducing a moving image signal , which comprises reading out and reproducing a stem stream . 2. The method for recording / reproducing a moving image signal according to claim 1, wherein :
A method of recording / reproducing a moving image signal, characterized in that a plurality of pieces of the processing time information are retrieved and the reproduction order of corresponding moving image signals is controlled by the processing time information. 3. The moving image signal recording / reproducing method according to claim 1, wherein the processing time information is information corresponding to a recording start time of the moving image. Recording and playback method. 4. The moving image signal recording / reproducing method according to claim 1, wherein the processing time information is information corresponding to a shooting start time of the moving image. Recording and playback method.