JPS61161087A - Video recording and reproducing device - Google Patents

Abstract

PURPOSE:To provide for still image reproduction without noise, vibrations of blurring by controlling so that video signals for reproduction stored in memory means are read out and derived during the mode of still image reproduction. CONSTITUTION:The reproduction mode is selected by pressing a reproduction command switch 262, while the reproduction of still images is selected by pressing a transient stop command switch 265. During reproduction, when the switch 265 is pressed, a transient stop mode output 401 is outputted by a tape running drive circuit 25. A latch circuit 410 latches the output 401 by head switch signals from a head switch signal generating circuit 400. The output from the circuit 410 is supplied to an analog switch 412 to open or close the switch while it is also supplied to a control circuit 411. The circuit 511 performs a control for a video memory 31 on the basis of head switch signals such as grasping from which of the magnetic heads 12, 13 the reproduction signals are derived.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a video recording and reproducing device, and particularly to a still image reproducing device (
The present invention relates to a video recording and reproducing apparatus (hereinafter abbreviated as VTR) which uses a memory to realize still playback (hereinafter referred to as still playback).

[Prior Art] First, before explaining still playback, video signal processing will be explained.

FIG. 3 is a block diagram showing the configuration of a conventional VTR. To explain the configuration of this device, as shown in the figure, a conventional VTR has magnetic tape 1. Magnetic head block 11.
Rotary transformer 23. Head switch signal generation circuit 4
00. Head changeover switch 22. Recording block 21.
Reproduction block 24. The a11 head block 11, which includes a tape running drive circuit 25 and a mode selection switch 26, is composed of magnetic heads 12 and 13, and the magnetic tape 1 is brought into contact with the pair of magnetic heads and run. The magnetic heads 12, 13 are provided on a head drum (not shown) so as to be exposed from its circumferential surface and to face each other in its diametrical direction. The magnetic heads 12 and 13 helically scan the running magnetic tape 1 while rotating together with the head drum, record video signals on tracks of the magnetic tape 1, and reproduce the recorded video signals from these tracks. The rotary transformer 23 is composed of transformers 231 and 232, and introduces the video signal to be recorded from the recording system block 21 to the magnetic head block 11 and leads out the reproduction signal from the magnetic head block 11 to the reproduction system block 24. The head switch signal generation circuit 400 generates a head switch signal for switching the magnetic heads 12, 13 based on the rotational phase of the head drum. The head changeover switch 22 consists of switches 221 and 222, and each magnetic head 12.13
The connection to the recording system block 21 or the reproduction system block 24 is switched. The recording system block 21 includes a video signal source 211 that provides a video signal including a luminance signal and a color signal, a luminance signal passing filter 212 that receives the video signal from the video signal source 211 and passes the luminance signal component, and Signal source 2
a color signal passing filter 213 that receives the video signal from 11 and passes the color signal component; and a luminance signal passing filter 213.
FMS modulator 2 that receives the luminance signal from 2 and performs frequency modulation.
14, a low frequency converter 215 that receives the color signal from the color signal pass filter 213 and converts it to a low frequency, and an adder circuit 216 that receives and adds the signals from the FM modulator 214 and the low frequency converter 215. It consists of The reproduction system block 24 includes the magnetic head block 11. rotary transformer 2
Head amplifiers 241 and 242 that amplify the reproduced video signal applied via the 3° head selector switch 22; an adder circuit 243 that receives signals from the head amplifiers 241 and 242 and adds them sequentially; and a reproduction signal from the adder circuit 243. an FM luminance signal passing filter 244 that receives a video signal and passes a frequency-modulated luminance signal component;
An FMS modulator 245 that receives the FM luminance signal from the second-degree signal passing filter 244 and performs FM demodulation, and an adder circuit 243
a low-pass color signal passing filter 246 that receives a reproduced video signal from and passes the low-pass-converted color signal component; and a low-pass color signal passing filter 246 that converts the low-pass color signal from the low-pass color signal passing filter 246 to a high frequency band. High frequency converter 247, FM (1m unit 2
It consists of an adder circuit 248 that receives the signal from 45 and the signal from the high frequency converter 247 and performs IIDI, and an output terminal 249 for outputting the signal from the adder circuit 248. One of the output terminals 249 is Grounded. The tape running drive circuit 25 drives and controls the running of the magnetic tape 1.

The mode selection switch 26 includes a recording command switch 261,
Regeneration command switch 262. Stop command switch 263. It consists of a high-speed reproduction command switch 264 and a pause command switch 265, and selects the operation mode of the VTR.

Next, the operation of this device will be described, but here, signal processing in recording mode will be omitted, and only signal processing in playback mode will be explained. In this case, the reproduction command switch 262 is pressed. In response, the tape running drive circuit 25 switches the switches 221 and 222 to the contact side, thereby switching to the playback system block 24. In this state, the video signal recorded on the A track of the magnetic tape 1 is reproduced by the corresponding magnetic head 12, and the transformer 231. Head amplifier 24 via switch 221
1 is given. The head amplifier 241 amplifies the supplied reproduced video signal and supplies it to the adder circuit 243. When the magnetic head 12 finishes reproducing the A track, the video signal recorded on the B track of the magnetic tape 1 is reproduced by the magnetic head 13 and transferred to the transformer 232. The signal is applied to the head amplifier 242 via the switch 222. head amp 242
amplifies the given reproduced video signal and supplies it to the adder circuit 243. The adder circuit 243 receives the magnetic head 1 from the A track.
2 reproduction video signal and the magnetic head 1 from the B track.
The three reproduced video signals are alternately selected based on the head switch signal and applied to the FM luminance signal passing filter 244 and the low frequency color signal passing filter 246. The FM luminance signal passing filter 244 is an FM variable II! FM demodulator 2
Give to 45. The FM demodulator 245 converts the FMH degree signal into FM
11 to derive a luminance signal and provide it to the adder circuit 248. On the other hand, the low-pass color signal passing filter 246 passes the low-tJA-converted color signal and supplies it to the high-pass converter 247 . The high frequency converter 247 converts the low frequency converted color signal into 3
．． It is converted into a 58 MHz color signal and applied to the adder circuit 248. Adding circuit 248 adds the luminance signal from FM demodulator 245 and the color signal from high frequency converter 247 and outputs the result to output terminal 249 as a video signal.

Next, still playback will be explained. VT as above
To control the running of the R magnetic tape, a control track is provided on the magnetic tape and a control signal is recorded on it.
This is done by reproducing control signals recorded from this control track. One method for noise-free still playback in VTRs using such a tape running control system is to use intermittent tape drive that repeats running and stopping during still playback, and repeats this process once or several times. Some devices are designed to stop the magnetically invasive tape. In order to obtain noise-free reproduced images using this method, when the tape is stopped, the positional relationship between the recording track and the magnetic head must always be within a range where no noise appears on the playback screen. In order to obtain this, the magnetic tape is stopped at a position where no noise appears on the screen by using the control signal that is reproduced while the tape is running as track position information, and controlling the amount of tape travel when this control signal is detected. ing.

Figure 4 shows a method of controlling still playback in such a conventional VTR. Figure 4 (a) shows the torque Mt applied to the capstan motor, and Figure 4 (b) shows the tape speed V. , and FIG. 4(C) show the control signal C, respectively. As is clear from this figure, in this control method, the magnetic tape is accelerated from time to to t, then the magnetic tape is run at a constant speed, and the magnetic tape is run at a constant speed until time t.
2, when the control signal C is detected, the delay time (tst
z) Braking is started and the tape speed V is almost zero at time t
4, the braking is stopped and the magnetic tape is stopped. Here, at the time of the above delay, 1'! I(t#-t2) is called the tracking delay time, and by increasing or decreasing this time,
The increase or decrease in tape feed when control signal C is detected increases or decreases.

Therefore, by adjusting this, the magnetic tape can be stopped where the reproduced image is best, that is, at the optimal tape stop position.

[Problems to be Solved by the Invention] Since the conventional video playback device is configured as described above, it takes time for the magnetic tape to stop and start the original still playback. In addition, the relative speed between the magnetic tape and the magnetic head changes depending on whether the magnetic tape is running or stopped, which may change the period of the reproduction horizontal synchronization signal and affect the mounting accuracy of the magnetic head.

There were drawbacks such as the playback screen shaking due to the stopping precision of the magnetic tape. Furthermore, in order to achieve shake-free still playback, playback using two magnetic heads with the same azimuth is required when the tape is stopped, so in addition to the two magnetic heads that normally perform recording and playback, one Alternatively, two magnetic heads for still reproduction were required.

The present invention was made in order to eliminate the above-mentioned drawbacks of the conventional apparatus, and an object of the present invention is to provide a video recording and reproducing apparatus that can realize still reproduction without noise, shaking, or blurring.

[Means for Solving the Problems] The video playback device according to the present invention stores the playback video signal in the storage means during the normal playback mode, and reads out the playback video signal stored in the storage means during the still playback mode. It is controlled so that it is derived.

[Operation] In the present invention, the instruction storage means stores the reproduced video signal in the normal reproduction mode, and the stored reproduced video signal is read out in the still reproduction mode.

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

In the description of this embodiment, the description of parts that overlap with the description of the conventional technology will be omitted as appropriate.

FIG. 1 is a block diagram showing the configuration of a VTR that is an embodiment of the present invention. The structure of this embodiment differs from the structure of FIG. 3 in the following points. A new video memory 31 for storing the reproduced video signal, a control circuit 411 and an analog switch 412 for controlling the writing of the reproduced video signal into this video memory and the reading and derivation of the reproduced video signal stored therein. ．． A latch circuit 410 is provided. The playback mode is set by the playback command switch 262.
Still reproduction is selected by pressing the pause command switch 265.

When the pause command switch 265 is pressed during playback,
Pause mode output 401 from tape running drive circuit 25
is output. The latch circuit 410 latches the temporary stop mode output 401 in response to the head switch signal from the head switch signal generation circuit 400. Latch circuit 410
The output is applied to an analog switch 412 and simultaneously applied to the control circuit 411 when this switch is opened or closed. The video memory 31 includes a luminance signal memory 3111 and a color signal memory 312, and also naturally includes a signal converter (not shown) required depending on the type of memory (digital type, analog type, semiconductor memory, magnetic memory, etc.). shall be taken as a thing. The control circuit 411 includes the video memory 3
1, memory address generation, IB write/read mode selection.

Based on the head switch signal, control is performed such as determining which of the magnetic heads 12 and 13 is the reproduction output.

FIG. 2 is a diagram illustrating the operation of a VTR that is an embodiment of the present invention. Figure 2 (a) shows the head switch signal,
FIG. 2(B) shows the temporary stop mode output, and FIG. 2(C) shows the latch circuit output.

Next, the operation of this device will be explained. Assume now that the magnetic chip 71 is loaded into the VTR and is in playback mode. In this state, 60 images (60 fields) are reproduced from the magnetic tape 1 per second in synchronization with the head switch signal. Hereafter, we will discuss still playback from this state.

When the pause command switch 265 is pressed, the pause mode is activated, and the pause mode output 401 becomes 0 in FIG.
As shown in FIG. 3, at the same time that the level becomes "H'" (indicating high potential), the tape running drive circuit 25 stops the running of the magnetic tee 71. At this time, the latch circuit r8410 latches the temporary stop mode output 401 at the rising edge of the head switch signal. The output of this latch circuit 410 is as shown in FIG. 2(C). In other words, this represents the period of writing to the video memory 31 at L' level (indicating a low potential) and reading at L' level.

Therefore, during the "L" level period, the video memory 31
At the same time, the analog switch 412 is ON and the input/output of the video memory 31 is in a short-circuited state, so that the reproduced video signal is output without passing through the video memory 31. Next, during the H'' level period in FIG. The content shown in Figure 2 (C) is the reproduced video signal one field before the signal in Figure 2 (C) reaches the 11H'' level.
This is the fourth "L" level period of the head switch signal shown in b).

To end the pause mode, press the pause command switch 26 again.
5 is pressed, the pause mode output 401 becomes "L level", and the tape running drive circuit 25 controls the start of tape running and enters the normal playback mode. In this state, the content from the video memory 31 and the original The reproduction video signal in the reproduction mode starts from the n+31st "H" level of the head switch signal in FIG. 2(a).

By the way, the content stored in the video memory 31 is, for example, the reproduced image 11m1fi of the magnetic head 12 when the head switch signal is at the low level.

Conversely, if the head switch signal is to store the H1 level, that is, the reproduced video signal from the magnetic head 13, the latch circuit 410. The head switch signal sent to the hunt control circuit 411 may be inverted.

As described above, since the present invention is constructed entirely of electronic 111JIll, it is possible to perform still playback with quick response.

In addition, since this invention reads out what has been written to the video memory once and uses it as a still image, the mounting accuracy of the magnetic head and the tape stopping accuracy during still playback are irrelevant, and the magnetic head used for normal recording and playback becomes irrelevant. Still playback without noise, shaking, or shaking is possible without adding a new magnetic head for still playback in addition to the magnetic head for still playback, and without changing the deck (mechanism). becomes.

Roughly speaking, from the above, the magnetic tape does not need to be in constant contact with the magnetic head, which protects the magnetic tape and enables long-time still playback.

In the above embodiment, a field memory is used as the video memory, but a frame memory may also be used.

Further, in the above embodiment, the video memory is divided into a luminance signal memory and a color signal memory, each of which stores a luminance signal and a color signal. Even in this case, the same effect as in the above embodiment can be obtained.

In addition, in the above embodiment, the case where the magnetic tape is stopped during still playback has been explained, but since the played video signal stored in the video memory is used as a still image, the above embodiment can be carried out without stopping the feeding of the magnetic tape. The same effect as in the example can be obtained, and in this case, audio can be played even while still images are being played.

[Effects of the Invention] As described above, according to the present invention, the reproduced video signal is stored in the storage means during the normal playback mode, and the reproduced video signal stored in the storage means is read out and derived during the still playback mode. With this control, still playback can be performed without noise, shaking, or blurring.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a VTR that is an embodiment of the present invention. FIG. 2 is a diagram illustrating the operation of a VTR that is an embodiment of the present invention. FIG. 3 is a block diagram showing the configuration of a conventional VTR. FIG. 4 is a diagram explaining the still playback operation in a conventional VTR. In the figure, 1 is a magnetic tape, 12, 13 is a magnetic head, 21 is a recording system block, 216, 243, 248 is an addition circuit, 22 is a head changeover switch, 23 is a rotary transformer, 241, 242 is a head amplifier, 24 is a Reproduction system block, 244 is FMIEI degree signal passing filter, 2
45 is an FM demodulator, 246 is a low-pass color signal passing filter,
247 is a high frequency converter, 25 is a tape running drive circuit, 26
is a mode selection switch, 262 is a reproduction command switch, 2
65 is a pause command switch, 31 is a video memory, 31
1 is a luminance signal memory, 312 is a color signal memory, 410 is a latch circuit, 411 is a foot roll circuit, and 412 is an analog switch. Note that the same reference numerals in each figure indicate the same or corresponding parts. Daisan Hito Oiwa Masu Yukin 1
Figure 3, 4th procedural amendment (voluntary) and 0 Name of the invention Video recording and reproducing device 3, Person making the amendment 5, Detailed explanation of the invention in the specification to be amended 6, Contents of the amendment (1) ) "Reading 11" on page 413, line 10 of the specification w
``Read out the ``L'' level period'' and ``Read the ``H'' level period''
Correct. (2) On page 14, line 15 of the specification, ``In the case of "L"level," is corrected to "In the case of M"L'level."that's all

Claims (1)

[Scope of Claims] A video recording and reproducing apparatus that records video signals on a magnetic tape with a plurality of magnetic heads and reproduces the video signals recorded from the magnetic tape, wherein the video signals are reproduced from the magnetic tape by each of the magnetic heads. a signal generating means for generating a signal for switching the reproduction signal of the video signal; a mode selection means for selecting a still reproduction mode of the video signal; a storage means for storing the reproduction signal; a control means for controlling the playback signal stored in the storage means to be read out and derived in response to a still playback mode selection output.