JPH08237588A - Disk recording and reproducing device - Google Patents

Abstract

PURPOSE: To provide a disk recording and reproducing device which is capable of easily performing an intermittent recording and a high speed reproduction and easily setting the intermittent recording, a fast forwarding reproduction, a normal recording and a normal reproduction according to times. CONSTITUTION: At the time of a recording, a header showing time information is added, data is transmitted for every frame and this data is stored in a cache memory 20. With this storage, the header is detected in a header detection circuit 23. According to the contents of this header, whether data is recorded or not is controlled within the cache memory 20. At the time of a reproduction, the data to which the header is added is reproduced and this data is stored in a cache memory 23. With this storage, the header is detected in the header detection circuit 23. According to the contents of this header, whether data is recorded or not is controlled within the cache memory. As a result, the intermittent recording and a variable-speed reproduction can be easily realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk recording / reproducing apparatus for recording / reproducing compression-coded video data and audio data.

[0002]

2. Description of the Related Art A hard disk is a storage device having a relatively large capacity and capable of high speed access. Therefore, a video recording / playback system has been proposed in which a video signal is recorded on a hard disk. Furthermore, it is considered to construct a video surveillance system using such a video recording / playback system.

That is, there is known a video surveillance system in which a video camera is attached to a bank or a store, and the inside of the store is photographed and recorded by the video camera. In such a video surveillance system, a magnetic tape is conventionally used as a recording medium. Then, the magnetic tape is intermittently fed to record for a long time. However, the magnetic tape requires a long access time. Instead of such a video surveillance system using magnetic tape,
When a video surveillance system using a hard disk is used, it becomes possible to access and display a screen at a predetermined time faster than a surveillance system using a magnetic tape.

Further, in a video surveillance system using such a hard disk, as shown in FIG. 6, it is desired that normal recording and intermittent recording can be switched according to the recording time. In FIG. 6, for example, normal recording is performed from time t ₀₀ to t ₀₁ , and time t ₀₁ to time t _02.
Intermittent recording is performed at, and normal recording is performed from time t ₀₂ to time t ₀₃ . In normal recording, a normal number of frames (for example, 30 frames per second in the NTSC system) is recorded, and in intermittent recording, N frames are recorded for 1 second.

At banks and shops, many customers come and go during business hours, and no one comes and goes after business hours. Depending on the recording time, if you can switch between normal recording and intermittent recording, you can record with a normal number of frames during business hours when many people come and go, and outside business hours when there are few people,
It can be intermittent recording.

[0006]

In a video surveillance system using a hard disk, it is necessary to control intermittent recording in order to enable long-term recording. Further, it is desired to perform control such that recording is performed with a normal number of frames at a certain time and intermittent recording is performed at a certain time.

However, the conventional hard disk drive unit simply records data at a designated address. Therefore, in the conventional hard disk drive unit, in order to perform control such as intermittent recording, recording at a normal number of frames at a certain time, and intermittent recording at a certain time, an external frame memory or this It is necessary to prepare a control circuit or the like for controlling the system, and there is a problem that the system becomes large.

Therefore, an object of the present invention is to provide a disk recording / reproducing apparatus which can easily perform intermittent recording and high speed reproduction.

Another object of the present invention is to provide a disc recording / reproducing apparatus capable of easily setting intermittent recording, fast-forward reproduction, normal recording and normal reproduction according to time.

[0010]

According to the present invention, there is provided a first interface for inputting / outputting a predetermined unit of data to which a header indicating time information is added, a second interface for inputting data selection information, and a predetermined interface. Temporary storage means for temporarily storing recording / reproducing data for each unit; header detecting means for detecting a header added to the recording / reproducing data;
The disk recording / reproducing apparatus is provided with a control means for controlling the temporary recording means based on the header.

[0011]

When recording, a header indicating time information is added, data is sent frame by frame, and this data is stored in the cache memory. Along with this, the header is detected. Recording / non-recording of data is controlled in the cache memory according to the content of the header. At the time of reproduction, the data to which the header is added is reproduced, and this data is stored in the cache memory. With this,
Header is detected. Depending on the content of this header,
Recording / non-recording of data is controlled in the cache memory. As a result, intermittent recording and variable speed reproduction can be easily realized.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an example of a video surveillance system using a hard disk drive device to which the present invention is applied. In FIG. 1, reference numeral 1 is a video camera for monitoring. The video camera 1 is attached to a position where a place to be monitored can be photographed. The video camera 1 takes a picture of the place being monitored. The image pickup signal of the video camera 1 is supplied to the A / D converter 2. A / D converter 2
Then, the image pickup signal is digitized. The output of the A / D converter 2 is supplied to the compression encoder 3. The compression encoder 3 is a compression encoder for compressing image data captured by the video camera 1 and digitized by the A / D converter 2. The output of the compression encoder 2 is supplied to the hard disk drive unit 4.
The imaged video data is stored in the hard disk drive unit 4.

Header information is supplied from the control unit 8 to the compression encoder 3. This header information can be time information, such as "year, month, day, hour,
Minutes, seconds, frames ". This header information is formed by the control unit 8 based on the time data from the timer 10. The record data is read from the encoder 3 in frame units, and header information is added to the record data in frame units.

The video data read from the hard disk drive unit 4 is supplied to the decompression decoder 5. The decompression decoder 5 decodes the compressed video data into the original video data. The output of the decompression decoder 5 is supplied to the D / A converter 6. The output of the D / A converter 6 is supplied to the display 7. The display 7 reproduces the video data stored in the hard disk drive unit 4.

The entire system consists of a control unit 8
It is managed by. The control unit 8 has
Input is given from the input unit 9. A timer 10 is also provided. Time is managed by this timer 10.

The hard disk drive unit 4 includes
Interfaces 11 and 12 are provided. The interface 11 is an interface for inputting / outputting data and addresses with an external system. Data is input from the encoder 3 via the interface 11. Further, the data is sent to the decoder 5 via the interface 11. Also, interface 1
An address is supplied from the control unit 8 via 1.

The interface 12 inputs / outputs control information.
This is the output interface. Control signals are exchanged between the control unit 8 and the hard disk drive unit 4 via the interface 12. The control signal includes selection information for selecting valid data from the cache memory 20.

The hard disk drive unit 4 includes
Disk controller / cache controller block 13, servo block 14, drive block 1
5 are provided.

The disk controller / cache controller block 13 includes a cache memory 20, a disk controller / cache controller 21, and a system controller 22. Further, the disk controller / cache controller block 13
Has a header detection circuit 23.

The cache memory 20 temporarily saves input / output data exchanged with an external system. The disk controller / cache controller 21 switches the internal mode of the hard disk to the read mode or the write mode according to the command sent from the external system, and performs control. Further, the disk controller / cache controller 21 controls the cache memory 20 and also performs error correction coding and error correction processing on the input output data.

As described above, the encoder 3 adds the header to the recording data. That is, FIG. 2 shows an example of the data. Recording data P1, P
2, P3 ... Have a size of one frame, for example.
Headers H1, H2, H3, ... Showing time information are added to the data P1, P2, P3. The header is detected by the header detection circuit 23. The detection information of this header is supplied to the system controller 22. The information in this header is used during N-frame intermittent recording or fast-forward / fast-forward reproduction, as will be described later.

In the read mode and the write mode, the disk controller / cache controller 21 consists of a transfer speed input via the interface 11 on the external system side and a drive block 15 for recording / reproducing to / from the magnetic disk 43. In order to absorb the difference in transfer speed, the cache memory 20 has a function of temporarily storing data. In the read mode, when the data read by the external system side remains in the cache memory 20, the operation of accessing the magnetic disk 43 is not performed, and the cache memory 20 sends the target data to the external system side. Control is done.

The disk controller / cache controller 21 includes a system controller 22.
The control signal is supplied from. As a result, the cache memory 20 can be controlled according to the header detection information.

The servo block 14 includes a voice coil actuator 30, a servo circuit 31, and a spindle motor 32. The voice coil actuator 30 is for moving the actuator arm 41 to move the magnetic head 42 in the radial direction of the disk. The spindle motor 32 rotates the magnetic disk 43. The servo circuit 31 is for moving the magnetic head 42 to a target position on the magnetic disk 43.

The drive block 15 is the magnetic disk 4
3, magnetic head 42, and actuator arm 41
And a modulation / demodulation circuit 40. Magnetic head 42
Are moved in the radial direction of the disk 43 by the actuator arm 41. The input signal is modulated by the modulation / demodulation circuit 40 and supplied to the magnetic head 42. The output signal of the magnetic head 42 is demodulated by the modulation / demodulation circuit 40 and output.

In the embodiment of the present invention, the header is added to the recording data as described above, and the cache memory 20 can be controlled according to the detection information of the header. As a result, it is possible to easily perform control such that recording is performed at a predetermined time and intermittent recording is performed during the predetermined time.

FIG. 3 is a flowchart showing such control. From the input unit 9, the recording start time t _0, the recording end time t _3, N times t ₁ to initiate the frame recording, N times t ₂ and ends the frame recording, and the frame number N when N frames recorded is input (Step S1). As a result, the recording start time t
₀ , recording end time t ₃ , N frame recording start time t ₁ , N frame recording end time t ₂ , and the number of frames N in the case of N frame recording are set.

By comparing the time information from the timer 10 with the recording set time t ₀ , it is judged whether or not the recording start time t ₀ has been reached (step S2). When the recording start time t ₀ is reached, a recording command is given from the system control unit 8 to the hard disk drive unit 4 (step S3).

Then, it is judged whether or not the N frame recording start time t ₁ has been reached (step S4). When the N-frame recording start time t ₁ is reached and is up to t ₂ , the N-frame recording command and the number of frames N are given from the system control unit 8 to the hard disk drive unit 4.

Then, it is judged whether or not the N frame recording end time t ₂ has been reached (step S6). When the N frame recording end time t ₂ is reached, an N frame recording end command is given (step S7). Then, it is determined whether or not the recording end time t ₃ has been reached (step S
8). When the recording end time t ₃ is reached, a recording end command is given (step S9).

FIG. 4 shows the processing when an N frame recording command is given. When an N frame recording command is given (step S11), the number of frames N is set (step S12). Then, the header of the transmitted data is detected (step S1
3) Based on this header information, it is judged whether the data is valid or invalid (step S14). That is, of the data for one second (for example, 30 frames), N frames are valid data, and the rest are invalid data. Then, the cache memory 23 is controlled so as to remove the invalid data (step S15). Then, only valid data is recorded (step S16).

FIG. 5 shows the operation of the cache memory 23 when recording N frames. For example, data P1 and P2 are recorded, data P3 is thinned out, and data P4 is recorded.
Let's record. In this case, the data P1, P2, P4
Is valid data, and the data P3 is invalid data.
As shown in FIG. 5A, the buffer B of the cache memory 13
One frame of data P1, P2, P3 for 1, B2, B3
And when storing the headers H1, H2, and H3 thereof, FIG.
As shown in, the data in the buffer B3 in which the data P3 is stored is deleted. Then, as shown in FIG. 5C, the next valid data P4 is stored in the buffer B3.

As described above, in the embodiment of the present invention, the headers H1, H2, ... Are detected and the cache memory 2 is detected.
Intermittent recording can be easily performed by controlling 3.

Further, in one embodiment of the present invention, it is possible to easily perform control such that the reproduction is started at a predetermined time and the fast-forward reproduction is performed during the predetermined time. That is, first, the reproduction start time, the reproduction end time, the time to start the fast-forward reproduction, the time to end the N frame reproduction, and the number of frames N in the case of N frame reproduction are input from the input unit 9. When the reproduction start time is reached, a reproduction start command is given from the system control unit 8 to the hard disk drive unit 4. It is determined whether or not it is the fast-forward playback time. If fast-forward playback, the fast-forward playback command and the number of frames N are given from the system control unit 8 to the hard disk drive unit 4. When the reproduction end time is reached, a reproduction end command is given from the system control unit 8 to the hard disk drive unit 4 by the number of frames N.

When a reproduction command is given, in the case of normal reproduction, the buffer B of the cache memory 20 is used.
Reproduction data is stored in 1, B2, and B3 for each frame, and these data are reproduced. When the fast-forward command for N frame reproduction is given, the header of the reproduction data is detected, and from the header, N frames are valid data, and the rest are invalid data. Then, the cache memory 2 is set so that invalid data is removed.
0 is controlled. Then, only the valid data is reproduced. As a result, fast-forward reproduction is performed.

[0036]

According to the present invention, at the time of recording, a header indicating time information is added, data is sent for each picture, and this data is stored in the cache memory. Along with this, the header is detected. Records data in cache memory according to the contents of this header /
Not controlled. At the time of reproduction, the data to which the header is added is reproduced, and this data is stored in the cache memory. Along with this, the header is detected. Depending on the content of this header, whether or not to reproduce the data is controlled in the cache memory. As a result, intermittent recording and variable speed reproduction can be easily realized.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a schematic diagram used to describe an embodiment of the present invention.

FIG. 3 is a flowchart used to describe an embodiment of the present invention.

FIG. 4 is a flowchart used to describe an embodiment of the present invention.

FIG. 5 is a schematic diagram used to describe an embodiment of the present invention.

FIG. 6 is a schematic diagram used to explain intermittent recording.

[Explanation of symbols]

 4 hard disk drive unit 11, 12 interface 20 cache memory 23 header detection circuit

Claims (3)

[Claims] 1. A first interface for inputting / outputting data of a predetermined unit to which a header indicating time information is added, a second interface for inputting data selection information, and recording / reproducing data for each predetermined unit. A disk recording / reproducing apparatus having a temporary storing means for temporarily storing, a header detecting means for detecting the header added to the recording / reproducing data, and a control means for controlling the temporary recording means based on the header. . 2. The disc recording / reproducing apparatus according to claim 1, wherein at the time of recording, the data stored in the temporary storage means is controlled according to the header of the input data to perform intermittent recording. 3. The disc recording / reproducing apparatus according to claim 1, wherein at the time of reproduction, the data stored in the temporary storage means is controlled according to the header of the reproduction data to perform high-speed reproduction.