JPH0527313B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an editing device for editing a still color video signal composed of at least one field.

Background technology and its problems For example, when playing back still images using a VTR, even if it is a direct color process VTR such as a broadcasting VTR, in order to achieve correct color reproduction regardless of discontinuity of color subcarriers, The following signal processing was performed on color video signals.
That is, a color video signal is once separated into a luminance signal and a carrier chrominance signal, the phase of the carrier chrominance signal is suitably inverted or non-inverted so as to maintain the continuity of the color subcarrier, and then the luminance signal is separated into a luminance signal and a carrier chrominance signal. and its phase-controlled carrier color signal are mixed.

Furthermore, in the case of recent VTRs, it has been proposed to control the displacement of a rotating magnetic head in a direction almost perpendicular to the scanning direction using an electro-mechanical conversion element such as a bimorph, making it possible to reproduce frame still images. has been done. Even in this case, normally the frame still color video signal is separated into the luminance signal and the carrier color signal as described above, the phase of the carrier color signal is suitably inverted or non-inverted, and then signal processing is performed to mix them again. It was on. The reason is NTSC or PAL
This is because, in the case of conventional television signals, one cycle of the color subcarrier cannot be completed with only one frame of color video signal, and color reproduction is impossible as it is.

However, signal processing that separates a color video signal into a luminance signal and a carrier color signal and inverts or non-inverts the phase of the carrier color signal causes deterioration of the characteristics of the color video signal, that is, deterioration of the image quality of the playback screen. This is the result. In particular, when the same color video signal is subjected to repeated signal processing, such as when editing a color video signal, the characteristics of the color video signal deteriorate accordingly.

Furthermore, when separating a color video signal into a luminance signal and a carrier color signal, a low-pass filter or a comb filter with better performance is used, but either way the spatial resolution of the luminance signal deteriorates and unnecessary signals are mixed in. However, the waveform characteristics deteriorate, and various signal deteriorations such as time delay of the carrier color signal, deterioration of the color band, and crosstalk between line signals occur, and these deteriorations are accumulated every time editing is performed.

Purpose of the Invention In view of the above, the present invention provides an editing device that edits a still color video signal composed of at least one field unit after correcting the time axis error.
This invention attempts to propose an editing device that can receive a still color video signal composed of at least one field unit as a good image on a monitor, and can edit and record it without deteriorating the signal characteristics. It is.

SUMMARY OF THE INVENTION The present invention provides a still color video signal in at least a field unit, which is reproduced from a reproduction tape by a reproduction VTR, to a time axis error corrector, corrects the time axis error, and then supplies it to a monitor receiver. In an editing device that supplies data to the recording VTR and performs editing and recording on the recording tape, the scanning trajectory of the recording head of the recording VTR is set to the standard even if the recording tape running speed is different from the standard speed. A head displacement control circuit that displaces the recording head to match the speed scanning locus, a control circuit that sets the playback position of the playback tape and the recording device of the recording tape, and a time axis corrector that When a color video signal is repeatedly and continuously played back from the playback VTR, the phase of the carrier color signal included in the time-axis corrected still color video signal is inverted at least in field units to reproduce the color of the still color video signal. A signal processing circuit that maintains the continuity of subcarriers and a still color video signal that is time-axis corrected according to a selection control signal are output on the recording side.
a selection circuit that selects the output of the signal processing circuit to be supplied as an input signal to the VTR and to the monitor receiver; a state signal representative of the phase state of the color subcarrier of the still color video signal; reference color framing information; a signal forming circuit that determines whether or not the input signal can be recorded by the recording VTR based on the position information of the recording tape, and outputs the determination result as a selection signal consisting of at least one field unit of a still color video signal. , recording side
A VTR transmits only an input signal, which is a still color video signal that has been time-axis corrected and is not processed by a signal processing circuit, to a predetermined position on the recording tape set by a control circuit for at least one field unit. , recording is performed in accordance with the scanning locus of the recording head at a standard speed.

According to the present invention, in an editing device that edits a still color video signal made up of at least one field unit after time axis error correction, the still color video signal made up of at least one field unit can be edited into a good image. Accordingly, it is possible to obtain an editing device that can monitor images as a monitor image and edit and record without deteriorating signal characteristics.

Embodiment An embodiment of the present invention will be described below with reference to FIG. 101 is the playback side VTR, 102 is the recording side
It's a VTR. Reference numeral 103 denotes a control device that controls both VTRs 101 and 102, and controls operation modes such as recording and playback of both VTRs, sets the position of the playback tape and recording tape, and sends reference synchronization signals and reference clocks to each VTR. It has functions such as supplying signals, etc.

104 is a time axis error corrector to which a color video signal obtained by FM demodulation from the reproduction side VTR 104 is supplied. This time axis error corrector 1
04 is equipped with a signal processing circuit 106 that inverts the phase of the carrier color signal of the frame still color video signal every other frame when the frame still color video signal is repeatedly and continuously reproduced from the reproduction side VTR 101. The signal processing circuit 106 includes a luminance/chrominance signal separation circuit, a carrier color signal phase inversion/non-inversion circuit, a luminance/chromaticity mixing circuit, and the like. SW is a changeover switch for switching between a frame still color video signal processed by the signal processing circuit 106 and a frame still color video signal not processed. This changeover switch SW has a movable contact a and fixed contacts b and c. The fixed contact b is connected to the terminal T1 from which the frame still color video signal processed by the signal processing circuit 106 is obtained, and the fixed contact c is connected to the terminal _T1 from which the frame still color video signal signal processed by the signal processing circuit 106 is obtained. Connected to the resulting terminal T ₂ . Also, the frame still color video signal from movable contact a is
The signal is supplied to the recording side VTR 102 and the monitor receiver 107.

105 is a time axis error corrector to which a color video signal obtained by FM demodulation from the recording side VTR 102 is supplied. Then, a signal-processed frame still color video signal from a signal processing circuit 106 similar to the signal processing circuit 106 of the time axis error corrector 104 is obtained at the terminal _T3 , and this is directly supplied to another monitor receiver 108. Ru.

Also, from the playback side VTR 101 to the recording side VTR 102
A subcarrier status signal SC-ST is provided representing the phase state of the black subcarrier. recording side
A recording preparation signal RR indicating that the recording side VTR 102 is ready to start a recording operation is supplied from the VTR 102 to the changeover switch SW of the time axis error corrector 104 as a control signal.

Next, the configuration of the time axis error corrector 104 shown in FIG. 1 will be explained with reference to FIG. 2. Playback side VTR
The FM demodulated color video signal obtained from the control circuit 101 is supplied to an A/D converter (not shown) and converted into a digital signal. is used to write and store in the memory 111. The frame still color video signal written in this memory 111 is transmitted to the read clock AFC circuit 109 of the control circuit 109.
It is read using the read clock signal from B. In this way, time axis errors in the digitized frame still color video signal are corrected.
Furthermore, the frame still color video signal read out from the memory 111 is supplied to a dropout correction processing circuit 112 and subjected to dropout correction processing, and then supplied to a signal processing circuit 113.

These memory 111, dropout correction processing circuit 112, and signal processing circuit 113 are all controlled by a controller 110 of the control circuit 109.
Further, the read clock signal from the read clock AFC circuit 109B is also supplied to the signal processing circuit 113. Then, the signal processing circuit 113 outputs a digitized frame still color video signal that has been processed to correct time axis errors, correct dropouts, and maintain continuity of subcarrier signals.

Next, the configuration of this signal processing circuit 113 will be explained with reference to FIG. The digitized frame still color video signal is provided to a delay compensation circuit 114 and a luminance/chromaticity separation circuit 116. The frame still color video signal from the delay compensation circuit 114 is supplied to the selector 115. Further, the luminance signal and the carrier color signal from the luminance/chromaticity separation circuit 116 are supplied to a signal processing circuit 117 that inverts the phase of the carrier color signal every frame, and the obtained luminance signal and carrier color signal are separated into luminance/chromaticity signals. Chromaticity mixing circuit 1
18 and mixed. The frame still color video signal obtained from mixing circuit 118 is supplied to selector 115 . This selector 115
corresponds to the switch SW in FIG. Further, the signal processing circuit 117 is controlled by a control signal to invert the phase of the carrier color signal or to pass it through as is. Further, the selector 115 switches between the frame still color video signal from the delay compensation circuit 114 and the frame still color video signal from the luminance/chromaticity mixing circuit 118 using a control signal (corresponding to the recording preparation signal RR). .

Next, the operation of this editing device will be explained. Playback side
When the frame still color video signal obtained from the VTR 101 is supplied to the recording side VTR for editing and recording, the control device 103 controls the playback side.
Set the tape positions of the VTR and the recording side VTR to the desired playback position and recording position, respectively, and turn the switch SW of the time axis error corrector 104.
Switching the movable contact a to the fixed contact b side, the FM demodulated frame still color video signal from the playback side VTR 101 is corrected for time axis error, and after signal processing by the signal processing circuit 106, the monitor image receiver 107 to confirm the frame still color video signal to be edited and recorded. After the recording preparations such as the position of the recording tape and recording timing conditions are completed, the recording preparation signal RR from the recording side VTR 102 {or from the control device 103} is sent to the time axis error corrector 1.
04 changeover switch SW, and switches the movable contact a to the fixed contact c side, and the reproducing side
The time axis error corrector 104 corrects the time axis error of the FM demodulated video signal obtained from the VTR 101, and the signal processing circuit 106 records the time axis corrected signal without signal processing. ~ side
It is supplied to the VTR 102 and edited and recorded on the magnetic tape. As will be described later, the recording preparation signal RR switches signals for at least one field unit, and the recording side VTR 102 edits and records the signals for at least one field unit on the magnetic tape. Incidentally, the recording track formed when recording on the magnetic tape is made to coincide with the inclined track at the standard speed by a head displacement control circuit as will be described later.

In the configuration shown in Fig. 1, when editing and recording, it is not possible to simultaneously receive the frame still color video signal to be edited and recorded on the monitor, but this is instantaneous and there is no practical problem in receiving the frame still color video signal. The monitor can receive the image. Note that in order to normally receive images on the monitor at all times, it is necessary to supply the frame still color video signal from terminal T ₁ directly to the monitor receiver 107 without providing a changeover switch, and to supply the frame still color video signal from terminal T ₂ directly to the monitor receiver 107. By supplying the signal directly to the recording side VTR 102, it is possible to receive the monitor image at the same time as editing and recording.

Now, for example, when collecting and editing a large number of one-frame still color video signals with explanatory audio recorded on a video disk,
Discontinuities in color subcarriers between different frame still color video signals are ignored and edited and recorded as they are unconditionally.

However, when placing importance on positional accuracy between consecutive signals, even for frame still color video signals, such as animation images, the recording side
As a recording condition for the VTR 102, the color framing of the CTL signal on the magnetic tape to be edited and recorded must match the still color framing of the frame still color video signal to be recorded. Therefore, in this case, the recording side
A detector is installed inside the VTR 102 to detect the state of the color subcarrier, and the detection signal is used to detect the recording side.
It is necessary to edit and record frame still color video signals while maintaining color framing on the magnetic tape by controlling the recording timing in the VTR 102. In other words, in simple still image recording such as an image signal from a camera, the playback CTL
is fixed and the color framing on the recording side changes alternately, so the detection signal of the phase state of the color subcarrier becomes a 15Hz pulse.

In addition, when editing and recording a frame still color video signal, which is the counterpart image for still image recording, without going through a signal processing circuit, a detector for detecting the phase state of the color subcarrier is also provided on the playback side VTR 101, and a reference It is necessary to compare it with the color fleming. The comparison output is then supplied to the recording side VTR 102 to control the recording signal gate circuit. By doing this, the frame still color video signal that is supplied to the recording side VTR for recording can be transferred to the playback side.
When recording by switching frame still color video signals from the VTR 101 and the television camera, recording with accurate color framing can be easily performed.

This point will be explained with reference to FIG. Figure 4A
shows the color framing PB-CF on the reproduction side of the x-th frame FR-x, and FIG. 4B shows the reference color subcarrier REF-SC to be compared with this. Fourth
Figures A and B show the case where the color framing of the x-th frame FR-x is in reverse phase with respect to the reference color subcarrier REF-SC. Figure 4 C and D show the color subcarrier REF-SC with reference color framing PB-CF on the reproduction side of the x-th frame FR-x.
This shows the case where it is in phase with . And the recording side
For example, in a VTR, the track immediately before the track to be recorded on the magnetic tape shown in FIG.
When the color framing REC-CF _o-1 of the (n-1)th frame FR-(n-1) matches the reference color subcarrier REF-SC of FIG. Recording color framing of the nth frame FR-n to be recorded on the next track in Figure G
REC−CF _o is the reference color subcarrier shown in Figure 4H.
If the phase does not match that of REF-SC, the recording gate circuit is closed and no recording is performed, and if they match as shown in Figure 4 I, the frame still color video signal of the xth frame in Figure 4 C is recorded. Open the gate circuit and record.

Next, referring to Figure 5, the recording side in Figure 1
An example of the VTR 102 will be explained. In addition, the playback side VTR
101 may also use the VTR shown in FIG.

Note that the VTR shown in FIG. 5 uses the control device 10 shown in FIG.
It is said to also have three functions.

The VTR shown in Figure 5 is based on the SMPTE type C VTR and has been improved upon. Fifth
In the figure, numeral 1 denotes a magnetic tape, which is obliquely wound and guided around a tape guide drum 2 in an Ω winding. Control signals are recorded in advance on the side edges of the tape 1. This wrapping angle is close to 360°. The winding state of the tape 1 on the tape guide drum 2, that is, the winding inclination and winding angle, are regulated by a pair of inclined guide pins 5 and 6.

The tape guide drum 2 is composed of a rotating upper drum 3 and a fixed lower drum 4. 7a is a recording/reproducing circuit magnetic head, and 7b is an erasing rotating magnetic head.These heads 7a and 7b are attached to the rotating upper drum 3 via a common electro-mechanical transducer 8 such as a bimorph, so that they can be connected in the scanning direction. It can be displaced in substantially orthogonal directions. Reference numeral 9 denotes a drum motor that rotationally drives the upper rotating drum 3, and is attached to the drum 3 via a shaft 10. Note that γ indicates the rotation direction of the rotating upper drum 3.

As shown in Figs. 6 and 7, the heads 7a and 7b have ring-shaped cores RC _a and RC _b respectively wound with coils L _a and L _b wound in a balanced manner in the former and single wound in the latter. There is. In addition, the coil L _b is connected to the core in order to avoid crosstalk between the erase signal and the recording signal.
It is wrapped around the leg of RC _b that is away from the head 7a. The gap G _a of the head 7a is provided at the center of the core RC _a . The gap _Gb of the head 7b is provided on one side of the core _RCb , closer to the head 7a. The gap G _b of head 7b is the same as that of head 7a.
has an azimuth for the gap G _a , and the head 7
It is said to be wider than the gap G _a of a. still,
The distance d between the opposing portions of the cores RC _a and RC _b is approximately 2 mm, which is quite close.

11 is a control magnetic head (wound magnetic head). 12 is a capstan, and 13 is a capstan motor for rotating the capstan 12. 14 is a pinch roller that rolls into contact with the capstan 12 via the tape 1. The tape 1 is held between the capstan 12 and the pinch roller 14, and as both rotate,
The tape 1 is made to run in the direction of arrow α at an arbitrary running speed depending on the rotational speed of the motor 13. In addition, in the case of the double capstan method, tape 1 is the positive
It can be driven in both directions at any speed.

Reference numeral 15 denotes a time axis expansion/contraction processing circuit on the recording side, to which an input video signal from an input terminal 16 is supplied. This circuit 16 receives a vertical synchronization signal (in the case of the NTSC system,
60Hz). Note that this vertical synchronization signal is a reference synchronization signal from the synchronization disc, and is obtained both during recording and reproduction.

17 is a servo circuit for the drum motor 9; The drum motor 9 includes signal generators (magnetic poles (magnetized magnet wheels) and magnetic heads (for example, thin film type A magnetic flux sensing head) is provided, and these signals are supplied to a servo circuit 17. The servo circuit 17 also includes a synchronous separation circuit 1 of the processing circuit 15.
A vertical synchronization signal (reference vertical synchronization signal) from the drum motor 9 is supplied from the servo circuit 17 so that each signal from the signal generator of the drum motor 9 is reliably locked to this vertical synchronization signal.
rotation is controlled. In this case, the rotation of the upper rotating drum 3 is prevented from fluctuating with the running speed of the tape 1.

Reference numeral 18 denotes an input terminal for a speed command signal that commands the running speed of the tape 1, which is generated when the operator operates a push button or the like of the speed controller. They are each controlled by being supplied to a speed control pulse generator 20. Pulses from the pulse generator 20 are supplied to a servo circuit 21 for the capstan motor 13. Further, a control signal from the microprocessor 19 is supplied to the pulse generator 20.

The microprocessor 19 controls VTR functions in response to command signals from a control panel (not shown), and sets the tape position to be recorded or played, and ensures that the signals to be recorded meet predetermined conditions. It determines whether the conditions are met, controls recording operations, etc.

22 is a position detector for detecting the running position of the tape 1 (the running position in the longitudinal direction of the tape), which receives a reproduction control signal from the control magnetic head 11 and is provided on the capstan motor 13; A frequency signal generator (consisting of magnetic poles (for example, a magnetized magnet wheel with 96 poles per revolution) and a magnetic head (for example, a thin film magnetic flux detection head)) that generates a frequency signal in accordance with the rotation of the motor 13, that is, the capstan 12. This frequency signal is supplied to the position detection circuit 22. This position detection circuit 2
2, the rough running position of the tape 1 is detected by the control signal, and the fine running position of the tape 1 is detected by the frequency signal. A position detection signal from the position detector 22 is supplied to the microprocessor 19 and the servo circuit 21.

The microprocessor 19 sets the position on the magnetic tape to be recorded (or reproduced) based on this position detection signal and a position designation signal based on a command from a control panel (not shown).

Further, the time axis expansion/contraction processing circuit 15 on the recording side receives a frequency signal from the frequency signal generator of the capstan motor 13, and performs time axis expansion/contraction processing of the video signal according to the frequency. The phase of the entire video signal is corrected based on the error signal from the servo circuit 21.

SW ₁ , SW ₂ and SW ₃ are recording/reproducing changeover switches, each having a movable contact m and fixed contacts p and r on the recording and reproducing sides, and are switched in conjunction with each other.

Reference numeral 23 denotes a head drive circuit that applies a drive signal from an output terminal 24 to the electro-mechanical transducer 8 to which the rotating magnetic heads 7a and 7b are attached, thereby displacing the head 7 in a direction substantially perpendicular to its scanning direction. . The head drive circuit 23 receives flyback pulses from the drum servo circuit 17 and generates a _phase -fixed triangular wave drive signal based on the flyback pulses. Based on the frequency difference between the frequency signals from the frequency signal generator, and the tracking error amount of the tracking error signal and the frequency difference between the horizontal synchronizing signals from the head displacement control circuit ₃₄ , which will be described later, obtained through the switch SW 1 during playback. to control the slope of the triangular wave drive signal, and furthermore, based on the error amount of the error signal from the capstan servo circuit 21 obtained via switch SW ₂ during recording, the head control signal obtained via switch SW ₂ during playback is controlled. The offset level of the triangular wave drive signal is controlled based on the phase of the horizontal synchronization signal from the displacement control circuit 34.

Next, the recording timing control circuit 30 will be explained. 25 is a modulator and recording amplifier which receives the color video signal from the time axis expansion/contraction processing circuit 15, frequency modulates and amplifies it, and controls the switch.
The signal is supplied from the output terminal 26 through the SW ₃ to the recording/reproducing rotary magnetic head 7a as a recording signal via a rotary transformer (not shown). Further, 37 is an erase signal generating circuit (oscillator) from which an erase signal (having a frequency slightly lower than twice the FM carrier frequency) is supplied from an output terminal 38 to the erase rotary magnetic head 7b. Modulator and recording amplifier 25
and the erase signal generation circuit 37 is the gate signal generator 27.
The recording/erasing timing and the recording/erasing period are controlled by the gate signal from the recording/erasing circuit.
This gate signal generator 27 is controlled by the microprocessor 19. 28 and 29 are framing discrimination circuits, of which 28 is an odd-even discrimination circuit that receives the video signal from the input terminal (the processing circuit 15 is also possible) 16 and discriminates whether the field is odd or even;
Reference numeral 29 denotes a color framing discrimination circuit which receives a video signal from the input terminal 16 (or the processing circuit 15) and discriminates its color framing. The discrimination outputs of these discrimination circuits 28 and 29 are supplied to the microprocessor 19. This discrimination output is a signal corresponding to the subcarrier status signal SC-ST. Also, this microprocessor 1
9, a vertical synchronization signal (reference vertical synchronization signal) from the synchronization separation circuit 15a of the time axis expansion/contraction processing circuit 15;
is supplied. 39 is a detection circuit that detects data from the control signal from the control head 11 (including color framing corresponding to each tilt track or odd/even data of the field) during the playback mode, and outputs the obtained detection output to the microprocessor. The data is supplied to the processor 19.

Based on these determination outputs and detection outputs, the microprocessor 19 determines whether the input video signal satisfies the color frame conditions that can be recorded on the magnetic tape. If the output of the position detection circuit 22 indicates that the magnetic tape is at the recording position, the microprocessor 19 generates a recording preparation signal RR.

Further, the reproduction signal from the recording/reproducing rotating magnetic head 7a is supplied to the reproduction amplifier and demodulator 31 via the switch SW ₃ and is amplified, and the frequency modulated color video signal is demodulated to produce a composite color video signal. is obtained, and is supplied to the time expansion/contraction processing circuit 32 on the playback side, subjected to time axis correction, and outputted to the output terminal 33.

Additionally, a horizontal synchronization signal in the composite color video signal from amplifier and demodulator 31 is provided to head displacement control circuit 34. The head displacement control circuit 34 also receives a reproduction signal (high frequency signal) from the recording/reproducing rotary magnetic head 7a from input terminals 35 and 36.
and a strain detection signal {a detection signal of the strain state of the element 8} from a mechanical-electrical transducer (not shown) such as a strain gauge attached to the electro-mechanical transducer 8.

Next, the recording operation of the video signal recording and reproducing apparatus shown in FIG. 1 will be explained with reference to FIG. 8 as well. Each movable contact of switches SW ₁ to _{SW 3} is a fixed contact r on the recording side.
can be switched to Set the running speed of tape 1 to the standard speed.
Let us consider the case where a video signal from the input terminal 16 is recorded on the tape 1 while running at a speed lower than S _o , that is, 1/m of the standard speed S _o . In FIG. 8, 1 indicates a magnetic tape similar to that in FIG.
CTL indicates control signals recorded on tape 1 in advance at equal intervals. T is tape 1 at standard speed
The inclined track (indicated by a solid line) is shown when the tape 1 is running at S _o , and T' is 1/m of the standard speed S _o .
The inclined track (indicated by the dashed line) is shown when the vehicle is traveling on a slope.

Therefore, in this video signal recording and reproducing apparatus (VTR), when the running speed of tape 1 is 1/mS _o , the inclined track has the same slope and the same length as the inclined track when tape 1 is running at the standard speed S _o . The video signal is recorded so as to form a tilted track T on the tape 1. In FIG. 8, α is the running direction of the tape 1, and β is the head 7.
The scanning directions are shown respectively.

Therefore, a speed command signal indicating that the running speed of the tape 1 is 1/mS _o (m can be arbitrarily selected) is supplied to the input terminal 18. In this way, the pulse generator 20 generates a pulse with a frequency 1/m times the frequency F _o of the pulse generated when the tape 1 is at the standard running speed S _o , and this pulse is generated by the capstan servo circuit 21.
supplied to Thus, the tape 1 is driven to run by the capstan 12 and the pinch roller 14 so as to run continuously at a speed of 1/ _mSo . The running speed 1/mS _o of the tape 1 does not change unless the microprocessor 19 supplies the pulse generator 20 with a control signal to change the speed.

In this case, the capstan is driven and controlled within a certain tape speed range lower than the standard recording and reproducing tape speed, thereby moving from a position near a recorded track to the next adjacent recording track position. At this time, the tape moves to the next track position in a short time, without going too far or overshooting the standard track interval, and the tape speed before and after reaching the adjacent track position is the standard recording/playback tape speed. Capstan control is performed to target the tape speed at a constant tape speed (including stationary) that is sufficiently lower than .

In addition, the time axis expansion/contraction processing circuit 15 adjusts the input video signal so that a unit signal of the input video signal, that is, one field (or one frame is also possible) is recorded on each inclined track T in FIG. While the video signal is being expanded, the capsulator is moved so that the arrival position of the inclined track T with respect to the control track CTL on the tape 1 coincides with the timing of the video signal to be recorded on the inclined track T. The phase of the expanded video signal is controlled based on the error signal from the servo circuit 21.

Further, the head drive circuit 23 drives the heads 7a and 7b.
The drum servo circuit 17, the frequency signal generator of the capstan motor 13 and the capstan servo circuit 21
The electro-mechanical transducer 8 is controlled by the electro-mechanical transducer 8. When the head 7a scans a certain inclined track T to record the video signal of a certain field, and then scans the adjacent inclined track T to record the video signal of another field, the head 7a
Only when the tilted track T cannot be scanned with only the displacements of a and 7b, the microprocessor 1
A pulse generator 20 is controlled by 9 so that the running speed of the tape 1 is slightly varied from 1/mS _o so that the heads 7a, 7b can scan the intended inclined track T. Therefore, the running of the tape 1 is controlled so that it can reliably scan a predetermined inclined track T by changing the possible range of the heads 7a, 7b.

In the modulator and recording amplifier 25, the ON/OFF state of the recording amplifier is controlled by the gate signal from the gate signal generator 27 (which is controlled by the microprocessor 19), and the time axis expansion/contraction processing circuit The supply/non-supply of the video signal subjected to time axis expansion/contraction processing from the recording/reproducing head 7a to the recording/reproducing head 7a is controlled. That is, from the video signal from the processing circuit 15, one field of video signal is extracted for every integer field close to m and is supplied to the head _7a via the switch SW3.

When recording a color video signal on the tape 1, the determination output of the color framing determination circuit 29 is used so that the color video signal is sequentially recorded on each inclined track T while maintaining the continuity of color framing. Based on the processing circuit 15
The video signals from the field are selected in field units.

Furthermore, when recording a monochrome video signal on the tape 1, the odd-even discrimination circuit 28 is set so that the monochrome video signal is sequentially recorded on each inclined track T while maintaining the continuity of the odd-even framing of the field. Based on the discrimination output,
Video signals from the processing circuit 15 are selected field by field.

9 and 10 show that even if the tape speed and position at the moment of recording are in an arbitrary state, it is restored and recorded into a normal pattern by sophisticated control of the head height vector P and signal phase vector Ψ. It is a vector diagram showing what can be done.

The standard recording speed vector v _r is, of course, the head scanning speed vector v _h and the tape speed vector v _t
is the composite vector of Now, if there is an arbitrary recording speed vector V _r at an arbitrary position, by adding the speed correction vector Δf to this, the vector (v _r
is obtained.

On the other hand, the positional deviation vector ΔΨ on the tape 1 is
This can be corrected by combining the video signal phase component vector (ΔΨ) and the track vertical movable head displacement vector (ΔP).

Furthermore, as can be seen from FIG. 10, the aforementioned Δf is obtained by combining the time differential values of ΔP and ΔΨ. Here, Δf becomes Δf=a→+b→. However, a=-
dP/dt, b=-dΨ/dt.

Thus, instead of a sloped track T' at a certain speed of the tape 1 (lower than the standard speed), the same sloped track T can be formed on the tape 1 at that speed as at the standard speed.

Next, we will discuss the frictional force in the tape running system. This problem fundamentally undermines the control possibilities for tape tension and tape guiding, especially when the tape is stationary or running in reverse.

For example, in the current SMPTE type C VTR,
Assume that the tape is running in the forward direction. At this time, the tension T(θ) distribution on the drum can be calculated as follows.

However, T ₀ : Tension at tape inlet μ : Fixed part friction coefficient θ _nax : Full wrap angle The moment the tape runs in the opposite direction, the distribution of tension T (θ) completely changes as shown in the following equation. It turns out.

So what exactly happens to the tension distribution from the moment the tape comes to rest until it runs in the opposite direction? Simply put, it can be said to be a state that can produce an infinite number of distribution curves.
In other words, when an elastic body in contact with a solid friction surface is strained by the frictional force, the strain distribution is free within the maximum strain slope determined by the equivalent frictional force and the equivalent modulus of elasticity. This is because it has the property of preserving the distribution state.

For example, the distribution at the moment when the tape comes to rest should belong to one of the above distribution calculation formulas. However, if one or both of the tensions on the entrance side or the exit side of the tape to the drum change as the tape stops running, how will the tension distribution along the way change? However, it is not easy to obtain a new distribution curve that continuously connects the tensions on the given inlet and outlet sides. An appropriate way to think of this is, for example, when one corner of a sand pile made of smooth sand collapses, creating another sloping part that corresponds to the tensions on both sides.

In other words, a continuum whose shape is held by solid friction exhibits a typical hysteresis phenomenon, and as a result, its shape as a continuum can have infinite uncertainty (diversity). This is similar to the shape of the sand mountain described above, which shows an infinite number of histories. It is also conceivable that such hysteresis will be eliminated by external micro-vibration disturbances and return to the ground state someday in the same way as, for example, a sand mountain is flattened.

Therefore, if you want a tension distribution on the dome surface that is exactly the same as that during standard speed recording, the following conditions must be observed. That is, the direction of tape friction must not be changed even slightly during or immediately before recording. To ensure this, it is necessary to record while the tape is running at a low speed, or to stop the tape gradually without overshooting, and to record immediately before tension relaxation occurs.

In addition, the tape during recording is not limited to running at a constant low speed.
Intermittent running is also fine. In this case, only a single block section in one field, frame, or other signal sequence is recorded in the flow of the signal to be recorded. After recording a single block, recording should be stopped immediately, or at least a pause interval should be provided. Further, after recording at least a series of signal blocks, the capstan drive is immediately commanded to stop, thereby stopping the tape at least within a distance shorter than the track pitch during standard speed continuous recording, and starting the next track at that position. Waiting for command to record. After waiting at this standby position, the next track is recorded in response to the next recording command.

Next, the operation of the apparatus shown in FIG. 5 when a part of the video signal recorded on the recorded tape is rewritten with a new video signal will be explained. Note that even if this recorded tape has a video signal recorded on it as described above by the apparatus shown in FIG. 1 while the tape is running at low speed or in a stationary state,
The video signal may be recorded normally by a SMPTE type C VTR at a standard tape running speed.

First, the movable contacts m of the switches _SW1 to _SW3 are switched to the playback side fixed contact p to set the playback mode, and the video signal of the recorded tape is sequentially played back as still images frame by frame, and the video signal to be rewritten is Determine. In this case, an intermittent tape running command signal is supplied to the input terminal 18, which causes the pulse generator 20 to generate intermittent pulses, and the tape 1
It is made to run intermittently every field, that is, every two tracks.

In this case, the head drive circuit 23 drives the head 7
A, 7b are controlled by the drum servo circuit 17 and the head displacement control circuit 34, and the electro-mechanical transducer 8
to drive.

The reproduced signal from the head 7a is supplied to the regenerative amplifier and demodulator ₃₁ via the switch SW3 and is received by the reproducing amplifier and demodulator 31.
After the FM modulated color video signal is FM demodulated, it is supplied to a time expansion/contraction processing circuit 32 for time axis correction, output to an output terminal 33, and reproduced on a monitor receiver (not shown).

In this way, once the portion of the video signal recorded on the recorded tape that should be rewritten, for example, the video signal for one frame, is determined, the tape 1 is switched to the recording mode while the tape 1 is stopped running. Each movable contact m of the switches SW ₁ to _{SW 3} is switched to the recording side fixed contact r. 1st in recording mode
The operation of the device shown in the figure is substantially as described above. however,
Here, it is necessary to erase the video signal of the frame to be rewritten before recording. Therefore, the erase signal generation circuit 37 generates an erase signal at substantially the same timing as the recording signal and supplies it to the erase head 7b.

Also, a recording/reproducing head 7a and an erasing head 7b
With the tape 1 still in a stopped state, the electro-mechanical transducer 8 sequentially scans the two inclined tracks T on which one frame worth of video signal to be rewritten is recorded. Erasing and recording of video signals for frames is performed. During this time, the head drive circuit 23 generates a head drive signal with a constant slope over the recording period of the video signal for one frame, and this is supplied to the electro-mechanical conversion element 8.

In addition, when rewriting and recording a color video signal on the recorded tape 1, the detection circuit 39 makes sure that the color video signal is sequentially recorded on each inclined track T while maintaining the continuity of color framing. Based on the detected color framing data of the recorded video signal, the processing circuit 15
The video signals from the field are selected in field units.

Furthermore, when a monochrome video signal is to be recorded on the tape 1, the detection circuit 39 is configured so that the monochrome video signal is sequentially recorded on each inclined track T while maintaining the continuity of the odd-even framing of the field. The video signals from the processing circuit 15 are selected field by field based on the detected odd-even data of the fields of the recorded video signal.

After rewriting and recording the video signal on the recorded tape 1 as described above, if the tape 1 remains stopped and the mode is switched again to the playback mode, the rewritten and recorded video signal can be played back as a still image and checked. Of course, this rewritten and recorded video signal can be rewritten and recorded any number of times.

Note that the number of circuit heads (for example, 2) and the winding angle of the tape with respect to the tape guide drum (for example,
180°) etc. are not limited to the above example but are arbitrary.

Further, the recording and reproducing rotary magnetic heads do not have to be used in combination, but may be separate heads. In this case, the electro-mechanical conversion elements to which these heads are attached may be common or separate.

According to the editing device described above, in the editing device that edits a frame still color video signal after correcting the time axis error, the frame still color video signal can be received on a monitor as a good image, and the deterioration of signal characteristics can be avoided. It is possible to edit and record without accompanying. In other words, there is no deterioration in the spatial resolution of the luminance signal, there is no contamination with unnecessary signals, there is no deterioration in waveform characteristics, there is no delay in the carrier color signal, there is no deterioration in the color band, there is no signal deterioration such as interference between lines, and there is no problem with repeated editing. However, there is no risk that the deterioration of those characteristics will accumulate.

Effects of the Invention According to the present invention described above, in an editing device that edits a still color video signal composed of at least one field unit after correcting a time axis error, the still color video signal composed of at least one field unit is edited. It is possible to obtain an editing device that can receive a good image on a monitor and edit and record without deterioration of signal characteristics. In other words, there is no deterioration in the spatial resolution of the luminance signal, there is no mixing of unnecessary signals, there is no deterioration in the waveform characteristics, there is no delay in the carrier color signal, there is no deterioration in the color band, there is no signal deterioration such as crosstalk between line signals, and there is no signal deterioration such as the same signal. There is no risk of the deterioration accumulating even if you repeatedly edit it.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the editing device according to the present invention, FIG. 2 is a block diagram showing the configuration of the time axis error corrector 104, and FIG.
A block diagram showing the configuration of the signal processing circuit 113 shown in the figure, FIG. 4 a waveform diagram used to explain the operation of the editing device shown in FIG. 1, and FIG. 5 a block diagram showing an example of a VTR that can be used in the present invention. , FIGS. 6 and 7 are a plan view and front view showing a part of the VTR shown in FIG. 5, respectively, FIGS. 8 and 9 are pattern diagrams showing recording patterns on the tape, and FIG. 10 is a vector diagram. It is. 101 and 102 are VTRs on the playback side and recording side, respectively;
Reference numerals 104 and 105 are time axis error correctors on the reproduction side and recording side, respectively, and numerals 107 and 108 are monitor receivers on the reproduction side and recording side, respectively.

Claims (1)

[Scope of Claims] 1. A still color video signal in at least a field unit, which is reproduced from a reproduction tape by a reproduction VTR, is supplied to a time axis error corrector to correct the time axis error, and then supplied to a monitor receiver, In an editing device configured to edit and record on the recording tape by supplying the tape to the recording VTR, even if the recording tape runs at a speed different from the standard speed, the scanning trajectory of the recording head of the recording VTR remains unchanged. a head displacement control circuit that displaces the recording head to match the scanning locus at the standard speed; a control circuit that sets the playback position of the playback tape and the recording device of the recording tape to predetermined values; and the time axis The corrector is provided to adjust the phase of the carrier color signal included in the time-axis corrected still color video signal at least in field units when the still color video signal is repeatedly and continuously played back from the playback side VTR. a signal processing circuit that determines and maintains the continuity of the color subcarrier of the still color video signal; and a signal processing circuit that determines the continuity of the color subcarrier of the still color video signal; a selection circuit that selects the output of the signal processing circuit to be supplied to the monitor receiver, a state signal representative of a phase state of a color subcarrier of the still color video signal, reference color framing information, and the recording side; a signal forming circuit that determines whether or not the input signal can be recorded by the recording side VTR based on tape position information, and outputs the determination result as the selection signal consisting of at least one field unit of the still color video signal; The recording side VTR receives only the input signal, which is a still color video signal that has been time-axis corrected and is not processed by the signal processing circuit, for at least one field unit, by the control circuit. An editing device characterized in that recording is performed at a predetermined position of the recording tape in accordance with the scanning locus of the recording head at the standard speed.