JP2006309827A - Video recording device and consecutive recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video recording device having no fear of deteriorating the responsiveness of consecutive recording when performing the consecutive recording and of exerting adverse influence of a picture quality at the time of performing the consecutive recording. <P>SOLUTION: When a REC switch is turned on again in order to resume recording, after a magnetic tape 1 resumes running and a capstan servo makes the magnetic tape run at a constant speed in a reproduction mode, a phase control circuit 6 applies a phase control by comparing a reproduced control signal with a reference signal and the phase control is locked at a C point and the changeover point of a next video signal, for example, the beginning part of odd-numbered fields is detected and the video signal is changed over at an R point, and the capstan servo is changed over to a recording mode at the R point and the recording of the video signal and the control signal are resumed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a video recording apparatus and a continuous shooting method for performing continuous shooting by interrupting and restarting video recording using a magnetic tape.

  A camera-integrated VTR (Video Tape Recorder) that records video captured by a video camera on a magnetic tape is widely used. When video is recorded with a camera-integrated VTR, continuous shooting is performed by interrupting and resuming recording for each cut, and recording is performed sequentially.

  FIG. 3 is a block diagram of a general VTR servo control circuit. In the recording (REC) mode, the video signal is recorded on the video track of the magnetic tape 1 by the video head 14 while the magnetic tape 1 is run by the capstan motor 2, and the control signal which is a tracking control signal is recorded by the control head 10. Recording on the magnetic tape 1. When recording the control signal, the reference signal 13 (30 Hz in NTSC) created from the vertical synchronizing signal of the video signal is recorded on the control track of the magnetic tape 1 via the recording circuit 9 and the REC terminal of the switch 11. The capstan motor 2 is speed-controlled so as to rotate at a predetermined speed by the speed control circuit 4 and the drive circuit 5 using a pulse from the FG detector 3 that detects the rotation speed. Further, a pulse from the FG detector 3 (hereinafter referred to as an FG pulse) is divided by a frequency dividing circuit 7 having a predetermined frequency dividing ratio to create a 30 Hz pulse, which passes through the REC terminal of the switch 12. And output to the phase control circuit 6. The phase control circuit 6 detects the phase between the pulse from the frequency divider circuit 7 and the reference signal 13, and the speed control circuit 4 mixes this phase difference and the FG pulse to control the phase of the capstan motor 2.

  In the reproduction (PB) mode, the switches 11 and 12 are switched to the PB terminal side, and the control signal reproduced from the magnetic tape 1 via the control head 10 is the PB terminal of the switch 11, the amplifier circuit 8, and the PB terminal of the switch 12. And is applied to the phase control circuit 6 through which the phase with the reference signal 13 is compared. Other speed control and phase control operations are the same as in the recording mode.

  Hereinafter, a servo control method in VTR splicing will be described as a first conventional example with reference to FIG. In the recording mode, the video signal is written on the oblique video track of the magnetic tape 1 and the control signal is written on the control track on the side edge of the magnetic tape 1. When the REC switch is turned off to interrupt the recording during the recording mode, the video track c and the control signal a are written and the recording is stopped at the point D. Then, at the time of resuming, in order to keep the video signal and control signal continuity at the joining point, the phase control is rewound (pre-rolled) from the point D so that the phase control is reliably locked between the points A and D. Wait at point A.

  When the REC switch is turned on again to resume recording, the magnetic tape 1 resumes running. At this time, the switches 11 and 12 are still on the PB side, the capstan servo is in the reproduction mode, and the capstan motor 2 rises up to a predetermined speed by the point B and runs the magnetic tape 1 at a constant speed. Further, the phase control circuit 6 compares the reproduced control signal with the reference signal 13 and applies phase control to lock the phase control at the point C. After point D, the capstan servo is switched to the recording mode, the switches 11 and 12 are switched to the REC (recording) side, and the video signal and the control signal are recorded.

  In addition, a video recording apparatus has been proposed in which the time for splicing is shortened (see, for example, Patent Document 1 below). Hereinafter, as a second conventional example, a servo control method in VTR continuous shooting disclosed in Patent Document 1 will be described with reference to FIG. FIG. 5 is a schematic diagram for explaining the joining operation of the magnetic recording / reproducing apparatus proposed in Patent Document 1. In FIG. As shown in FIG. 5, in the recording mode, video, audio, and control signals are recorded in a portion up to point G on the magnetic tape. When the REC switch is turned off at point G, the video signal is written on the video track j (position of the control signal e) and recording is stopped. Audio recording stops as well. However, the magnetic tape 1 continues to run, and the control signals f, g, and h are recorded following the control signal e, and the recording is stopped at the point I. After that, pre-roll from point I to point E and wait.

When the REC switch is turned on again, the capstan servo enters the reproduction mode, the speed control loop is locked up to point F, and the magnetic tape 1 runs at a constant speed. Then, recording of the video signal and the audio signal is resumed at the point G. On the other hand, in the phase control, the reproduced control signals e, f, g, and h are compared with the reference signal, and the control is performed in the reproduction mode after the G point, the phase is locked at the H point, and the recording mode is performed after the I point. Instead, the control signal i is recorded.
JP-A-6-349160 (paragraphs 0015 and 0016, FIG. 1)

  By the way, in a news gathering scene called ENG (Electric News Gathering), when an incident or accident occurs, the photographer who wants to start recording immediately. Therefore, the time from when the cameraman presses the recording start button until recording actually starts, that is, the response of joining shots becomes a problem. However, in the servo control method in the first conventional example, the pre-roll time is determined so that the phase control is reliably locked between the points A and D in order to maintain the continuity of the video signal and the control signal at the joining point. Therefore, it is necessary to determine the pre-roll time with a sufficient margin for the lock time. Therefore, the pre-roll time is set in accordance with the environment change and the worst state of variation. In most cases, the pre-roll time is too long with respect to the lock time, and the recording restart timing is late.

  Further, in the servo control method in the second conventional example, from the point G to the point I, the pitch of the video tracks k, l, m after the restart is different from the pitch before the video track j before the interruption, and the video track n Thereafter, since the phase control is in a locked state, the pitch returns to the normal pitch. For this reason, there is a problem in that tracking deviation occurs at the point G during reproduction, and the output of the video track is partially reduced during splicing, which adversely affects image quality. As described above, the conventional video recording apparatus has a problem that the responsiveness of the pegging is bad when performing the pegging, or the image quality may be adversely affected during the pegging.

  The present invention has been made in view of the above-described problems of the conventional example, and it is an object of the present invention to provide a video recording apparatus and a continuous shooting method that have a good response for connecting shots and do not adversely affect image quality.

In order to achieve the above object, the present invention
A tape running means (2) for running the magnetic tape (1);
Video signal recording means (14) for recording an input video signal having a plurality of field configurations on the magnetic tape (1);
Control signal recording means (10) for recording a control signal for tracking control generated based on the input video signal on the magnetic tape (1);
Control signal reproducing means (10) for reproducing a control signal recorded on the magnetic tape (1) by the control signal recording means (10) to obtain a reproduction control signal;
Tape running speed detecting means (3) for detecting the running speed of the magnetic tape (1);
Tape running speed control means (4) for controlling the running speed of the magnetic tape (1) by driving the tape running means (2) based on the detection signal of the tape running speed detecting means (3);
After the tape running speed control means (4) controls the running speed of the magnetic tape to a constant speed, the phase of the reproduction control signal acquired by the control signal reproduction means (10) and the phase of the input video signal In a video recording apparatus comprising phase control means (6) for controlling the running phase of the magnetic tape (1) by driving the tape running means (2) based on the difference,
When moving from the recording state in which the input video signal and the control signal are recorded while the magnetic tape (1) is running to the recording stop state, the magnetic tape (1) is stopped in the reverse direction. When the recording tape is rewound by a predetermined amount and stopped, and when the recording state is shifted from the stopped state to the recording state again, the traveling of the magnetic tape (1) is resumed and the traveling phase of the magnetic tape by the phase control means (6) is locked. The image processing apparatus is characterized by further comprising a joining means (control shown in FIG. 1) for resuming recording of the input video signal at the time of switching of the field of the input video signal immediately after being performed.

In order to achieve the above object, the present invention
A video recording apparatus for running a magnetic tape and recording an input video signal having a plurality of field configurations on the magnetic tape and recording a control signal for tracking control generated based on the input video signal on the magnetic tape In the method of taking pictures in
When moving from the recording state where the input video signal and the control signal are recorded while the magnetic tape is running to the recording stop state, the magnetic tape is stopped and then rewound by a predetermined amount in the reverse direction. Tape rewinding step to be stopped (between D and A in FIG. 1);
When transitioning from the stopped state to the recording state again, after the traveling of the magnetic tape is resumed and the traveling speed of the magnetic tape is controlled to a constant speed, the phase of the reproduction control signal and the phase of the input video signal are A phase control step (steps S01 to S04 in FIG. 2) for controlling the running phase of the magnetic tape based on the difference;
A phase lock determining step (step S05 in FIG. 2) for determining that the phase of the running control of the magnetic tape is locked;
A switching time determination step (step S06 in FIG. 2) for determining the switching time of the field of the input video signal immediately after determining that the phase is locked in the phase lock determination step;
And a recording restarting step (step S07 in FIG. 2) for restarting recording of the input video signal when the switching time is determined in the switching time determination step.

  According to the present invention, during continuous shooting, phase control is performed after speed control is performed by running the tape with the tape running means when recording is resumed, and video recording is resumed when the video signal is switched when phase control is completed. Therefore, it is possible to provide a video recording apparatus that has a good response for splicing and does not have a negative effect on image quality.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram for explaining an operation of joining shots of the video recording apparatus according to the embodiment of the present invention, and FIG. 2 is a flowchart of joining pictures of the video recording apparatus. A block diagram of a servo control circuit of a VTR that is an example of a video recording apparatus in the present embodiment will be described with reference to FIG.

  The processing shown in FIGS. 1 and 2 is performed by the video recording apparatus shown in FIG. In the recording mode, the video signal is written on the oblique video track of the magnetic tape 1 by helical scanning, and the control signal is written on the control track on the side edge of the magnetic tape 1. When the REC switch is turned off to stop recording during the recording mode, recording stops at point D after the video track c and control signal a are written. Then, a predetermined amount is rewound (pre-rolled) from point D and waits at point A. Here, point B is the time when the speed control lock is completed, and point C is the time when the phase control lock is completed.

  When the REC switch is turned on again to resume recording, the magnetic tape 1 resumes running from point A (step S01). At this time, the switches 11 and 12 are still on the PB side, the capstan servo is in the reproduction mode, and the capstan motor 2 rises to a predetermined speed at point B (step S02). Thereafter, the magnetic tape 1 Is driven at a constant speed (step S03), and then the control signal reproduced by the phase control circuit 6 is compared with the reference signal 13 to apply phase control (step S04).

  When phase control is locked at point C (YES in step S05), the switching point of the next video signal, for example, the beginning part of the odd field is detected (step S06). When it is detected that the video signal is switched at the R point (YES in step S06), the capstan servo is switched to the recording mode at the R point, the switches 11 and 12 are switched to the REC (recording) side, and the video signal and the control signal are recorded. Resume (step S07). As a result, overwriting is started from the video track r before the video track c at the previous recording, and the control track starts overwriting from the point s before the control signal a at the previous recording. Thereby, since the recording can be started in the shortest time after the capstan servo is locked, the response of the joining shot is good when the joining shooting is performed. In addition, since the capstan servo is always locked when recording is resumed, there is no possibility of adversely affecting the image quality at the time of continuous shooting.

  Here, between the R point and the D point, the video signal recorded immediately before joining shot is overwritten and erased. However, when recording with ENG or the like, it is longer considering the later editing work. Since it is normal to record the data in the file, there is no problem even if it is overwritten. Also, if the servo lock takes a long time due to environmental changes, variations, etc., the point C where the phase is locked will be shifted backward, but it will be the same as the first conventional example even if it is shifted most. There is nothing worse than that.

  As described above, the video recording apparatus according to the embodiment performs phase control after speed control by running the tape with the tape running means at the time of resuming recording at the time of resuming recording. Since the recording of the video is resumed in this manner, it is possible to provide a video recording apparatus that does not have a poor response of the pegging when performing a pegging, or that may adversely affect the image quality during the pegging. In this embodiment, an example in which the control signal is driven into the end of the tape is shown. Needless to say, the present invention can be applied to a DVC standard digital VTR that does not use a control signal.

It is a schematic diagram explaining the operation | movement of a continuous shooting of the video recording device which is embodiment of this invention. It is a flowchart of the continuous shooting of the video recording apparatus which is embodiment of this invention. It is a block configuration diagram of a servo control circuit and the like of a conventional video recording apparatus. It is a schematic diagram explaining the operation | movement of the joining photography in a 1st prior art example. It is a schematic diagram explaining the operation | movement of the joining photography in a 2nd prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic tape 2 Capstan motor 3 FG detector 4 Speed control circuit 5 Drive circuit 6 Phase control circuit 7 Dividing circuit 8 Amplifying circuit 9 Recording circuit 10 Control head 11, 12 Switch 13 Reference signal 14 Video head

Claims (2)

A tape running means for running the magnetic tape;
Video signal recording means for recording an input video signal having a plurality of field configurations on the magnetic tape;
Control signal recording means for recording a control signal for tracking control generated based on the input video signal on the magnetic tape;
Control signal reproduction means for reproducing a control signal recorded on the magnetic tape by the control signal recording means to obtain a reproduction control signal;
Tape running speed detecting means for detecting the running speed of the magnetic tape;
Tape running speed control means for controlling the running speed of the magnetic tape by driving the tape running means based on the detection signal of the tape running speed detecting means;
After the tape running speed control means controls the running speed of the magnetic tape to a constant speed, the tape is based on the difference between the phase of the playback control signal acquired by the control signal playback means and the phase of the input video signal. In a video recording apparatus comprising phase control means for driving the travel means to control the travel phase of the magnetic tape,
When moving from the recording state where the input video signal and the control signal are recorded while the magnetic tape is running to the recording stop state, the magnetic tape is stopped and then rewound by a predetermined amount in the reverse direction. In addition to stopping, when shifting from the stopped state to the recording state again, the traveling of the magnetic tape is restarted and the field of the input video signal immediately after the traveling phase of the magnetic tape is locked by the phase control means A continuous shooting means for resuming recording of the input video signal at the time of switching,
A video recording apparatus comprising: A video recording apparatus for running a magnetic tape and recording an input video signal having a plurality of field configurations on the magnetic tape and recording a control signal for tracking control generated based on the input video signal on the magnetic tape In the method of taking pictures in
When moving from the recording state where the input video signal and the control signal are recorded while the magnetic tape is running to the recording stop state, the magnetic tape is stopped and then rewound by a predetermined amount in the reverse direction. A tape rewind step to stop,
When transitioning from the stopped state to the recording state again, after the traveling of the magnetic tape is resumed and the traveling speed of the magnetic tape is controlled to a constant speed, the phase of the reproduction control signal and the phase of the input video signal are A phase control step for controlling the running phase of the magnetic tape based on the difference;
A phase lock determining step for determining that the phase of the running control of the magnetic tape is locked;
A switching time determination step of determining a switching time of the field of the input video signal immediately after determining that the phase is locked in the phase lock determination step;
A recording restarting step for resuming recording of the input video signal when the switching time is determined in the switching time determination step;
A joining method characterized by having.

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