JPH0695769B2 - Video signal discrimination device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a video signal discriminating apparatus for discriminating framing or color framing of a plurality of video signals.

2. Description of the Related Art In recent years, the video signal discriminating apparatus has become indispensable in a video signal switching apparatus and a video signal recording / reproducing apparatus. For example, in a video signal recording / reproducing apparatus, when another signal is continuously and continuously recorded from any part of a recorded tape (referred to as insert editing or assemble editing), framing of a signal to be reproduced and a signal to be recorded next is performed. Match the color framing, and at the edit point,
If you do not disturb the order of framing or color framing, distortion (called skew) at the top of the TV screen, color flash (color skipping), etc. will occur at the edit point. Therefore, in order to prevent such a problem, a framing or color framing video signal discrimination device is required.

FIGS. 5, 6, and 7 show specific examples of the conventional video signal discriminating apparatus. Editing of helical scan method in Fig. 5
The block diagram of the framing discrimination device in VTR is shown. In FIG. 5, 51 is a first framing discrimination device, 52 is a second framing discrimination device, 53 is a phase comparator, 54 is a VTR control device, 55 is an input video signal of VTR, and 56 is VT.
R reproduced video signals, and 57 and 58 are framing signal outputs.

The operation of the conventional video signal discriminating apparatus configured as described above will be described below. The VTR for editing realizes beautiful editing of the seam by outputting the reproduced video signal 56 (called run-up period) and changing to the recording state at a specific editing point. However, if the VTR playback video signal 56 and the framing of the video signal 55 to be recorded next (there are two types, even field and odd field, with the vertical synchronization period as one unit), the TV at the editing point. The skew that the upper part of the screen of John is distorted occurs. In order to avoid this, the framing of the two video signals is discriminated during the run-up period, and if the framing is different, VTR
The phase of the rotating cylinder is shifted by 180 degrees to match the phase, and the joining of images without skew at the editing point is realized. In FIG. 5, the VTR input video signal 55 is input to the first framing discrimination device 51, and the VTR playback video signal 56 is input.
Is input to the second framing discrimination device 52. The two framing discrimination devices 51, 52 output framing signals 57, 58 which are 1/2 frequency of the vertical synchronizing signal. These two signals are taken into the phase comparator 53, and if the framing is different, a signal is sent to the VTR controller 54, which shifts the phase of the rotary cylinder by 180 ° and reproduces the video signal 56. Can be shifted to match the framing phase of the two signals 55, 56.

However, this framing discrimination device requires a complicated circuit configuration as shown in the block diagram of FIG. In FIG. 6, 57 and 58 are the same framing signal outputs as in FIG. 5, and 55 and 56 are the same video signal inputs. 60 is a composite sync signal separation circuit, 61 is a 10 μsec mono-multivibrator, 62 is a D flip-flop, 63 is a crystal oscillator, 64
Is a gate, 65 is a counter, 66 is an AND gate, 67 is a mono-multivibrator, 68 is an AND gate, 69 is a 1/2 divider circuit,
Reference numeral 70 is a composite synchronizing signal, 71 is a clock signal, and 72 is a vertical synchronizing signal. Further, FIG. 7 shows the waveforms of each part.

Regarding the framing discrimination device configured in this way,
The operation will be described below. The video signals 55 and 56 pass through the composite sync signal separation circuit 60, and the composite sync signal 70 is taken out. The composite sync signal 70 is input to the 10 μsec mono multivibrator 61. The time of 10 μsec is selected to be wider than the time width of the horizontal sync signal and narrower than the time width of the vertical sync signal. The output 71 of the mono multivibrator 61 is input to the clock input of the D flip-flop 62, and the composite synchronizing signal 70 is input to the D input of the D flip-flop 62.
Is entered. Then, the output waveform 72 of the D flip-flop 62 becomes a vertical synchronizing signal as shown in FIG. As shown in Fig. 7, there is always a time axis between the input video signal and the obtained vertical sync signal, rather than using a CR filter to simply separate the vertical sync signal. There is a deviation of 10 μm in the example of FIG.
While it is constant at sec, the vertical sync signal obtained by the CR filter has an extremely unstable shift amount especially in terms of temperature characteristics.If this shift amount is not stable, there is a high possibility that the framing discrimination will be canceled. is there.

The vertical synchronizing signal 72 resets the counter 65 which uses the output of the crystal water shaker 63 as a clock input signal. The crystal oscillator 63, the gate 64, the counter 65, and the AND gate 66 constitute a mono-multi, and this is not a simple CR mono-multi but has a complicated configuration for the same reason as above. The counter 65 is reset by the vertical synchronizing signal, then counts up by the output signal of the crystal oscillator 63, and when the constant value is reached, the AND gate 66 outputs. This output triggers the next mono multivibrator 67 and at the same time gate
Stop 64 and prevent counter 65 from further counting up. The mono multivibrator 67 outputs the pulse 73 shown in FIG. This pulse 73 and composite sync signal 70
Go through D-gate 68. For example, 66-69 in mono-multi configuration
Select a delay amount of 7H and set the width of the mono multivibrator 67 to
If you select about 10 μsec, as shown in Fig. 7, the video signal overlaps the output of the mono multivibrator 67 of 73 like the waveform of 74 in the even field, and the waveform of 75 in the odd field. The horizontal sync signal is shifted from the output of the mono-multivibrator 67 of 73 as shown in. Therefore, the AND gate 68 outputs the even field detection signal. Since the 1/2 divider circuit 69 uses the vertical synchronizing signal 72 as a clock and the output of the AND gate 68 as a reset input, its outputs 57 and 58 are rectangular waves with a frequency of 1/2 of the vertical synchronizing signal, and are used for framing. It is a discrimination signal. Also,
In the color framing discriminating apparatus, in addition to the above circuits, a color burst sampling circuit, a burst frequency oscillator, an integrator and the like and peripheral circuits are added, and the circuit configuration becomes more complicated.

SUMMARY OF THE INVENTION However, in the above-mentioned configuration, if two complicated framing or color framing circuits are not provided, framing or color framing of two signals cannot be performed. There is a problem in terms of cost.

The present invention solves the above-mentioned problems, and framing or color framing is made into one circuit, and a plurality of video signals are selectively inputted, so that the framing or color framing of a plurality of video signals can be discriminated by this one circuit. Even if the video signal is not input to the discriminating circuit, a simple circuit holds the framing or color framing information obtained when the video signal is input to the discriminating circuit. It is an object of the present invention to provide a video signal discriminating device capable of processing all video signals with a single framing or color framing discriminating device.

Means for Solving the Problems In order to solve the above problems, the present invention is a video signal discriminating apparatus for discriminating coincidence by comparing framing or color framing among a plurality of video signals, and framing the video signals. Alternatively, a discriminating means for discriminating color framing, a switching means for selectively inputting the plurality of video signals to the discriminating means, a holding means for respectively holding a discrimination result for each video signal by the discriminating means, and the holding means. And a comparing / determining means for comparing the output signals of the holding means and the output signal of the determining means to determine a match, and the holding means is provided with the framing or color of the corresponding video signal. A counter that counts electric signals having a period corresponding to the framing period and is reset by the output signal of the discrimination means. Or delay means for delaying the output signal of the discriminating means for a certain period of time.

According to the present invention, according to the above configuration, a plurality of video signals are sequentially input to one framing or color framing discriminating means by using the switching means, each framing or color framing is discriminated, and the judgment results are respectively held. Therefore, the framing or color framing discriminating means, which is required in the same number as the video input signal, can be integrated.

Example Hereinafter, an example of the video signal discriminating apparatus of the present invention,
A description will be given with reference to the drawings.

FIG. 1 shows a block diagram of an embodiment of the present invention, taking an apparatus for discriminating color framing in a PAL VTR as an example. In FIG. 1, 1 is an input video signal of the VTR,
2 is a VTR playback video signal, 3 is a video signal selector switch,
Reference numeral 4 is a color framing discrimination device, 5 is a reset signal output changeover switch, 6 is a rectangular wave oscillator, 7 is a changeover command signal, 8 is a counter reset signal, 9 is a first vertical synchronizing signal separation circuit, and 10 is a second vertical sync signal. Sync signal separation circuit, 11 is a first 2-digit binary counter, 12 is a second 2-digit binary counter,
Reference numeral 13 is a two-bit digital comparator, 14 is a counter coincidence signal, 15 is a VTR controller, and 16 and 17 are vertical synchronizing signals.

The operation of the video signal discriminating apparatus configured as described above will be described below with reference to FIG. Consider an editing operation that starts recording the input video signal at a certain point while the PAL VTR outputs the playback video signal. At this time, if the color framing of the input video signal 1 and the color framing of the VTR playback video signal 2 do not match, color skipping (color flash) occurs at the editing point. To avoid this, the VTR compares the color framing of the two signals during the period during which the playback video signal is output before recording (the so-called run-up period), and if they do not match, speed up the VTR playback speed. By slowing down or the like, the color framing of the two signals can be matched by the start of recording, whereby perfect editing without color flash can be realized. In performing this operation, the color framing of the two signals is determined.

In PAL color framing, there are two types of luminance signal, the first field signal and the second field signal, the burst signal is switched between + 135 ° and −135 ° for each horizontal synchronizing signal, and one vertical synchronizing signal is 625. Since the number of horizontal synchronizing signals is one and the number of the horizontal synchronizing signals is odd, there are four types of signals, two types of which the vertical synchronizing signal is one unit.

In FIG. 1, the rectangular wave oscillator 6 is selected to have a duty of 50% and a frequency equal to or less than 1/8 of the vertical synchronizing signal frequency of 50 Hz. In addition, the switching command signal 7 which is a rectangular wave signal output
When is high, the video signal changeover switch 3 and the reset signal output changeover switch 5 are connected to the solid line side, and when low is, these changeover switches 3 and 5 are connected to the broken line side. When the switching command signal 7 is high, the VTR input video signal 1 is connected to the color framing discrimination device 4. The color framing discrimination device 4 is configured to output a counter reset signal 8 which is a signal output only when a specific one type of four types of video signals (hereinafter referred to as a first signal) comes. . The counter reset signal 8 is input to the reset input of the 2-digit binary counter 11 through the changeover switch 5, and the counter 11 becomes 0 at this time. At the same time, the counter 11 receives the vertical synchronizing signal 16 separated from the input video signal 1 through the vertical synchronizing signal separating circuit 9 as a clock input. Since this counter 11 is a two-digit binary, it operates as 0 → 1 → 2 → 3 → 0 → 1 → ....
As described above, since the 2-digit binary counter 11 is reset by the counter reset signal 8, the counter 11 is set to 0 while the switching command signal 7 output from the rectangular wave oscillator 6 is high.
When, the color framing of the input video signal 1 coincides with the first signal. Since the order of the four types of signals related to color framing is fixed in the continuous signal, the switching command signal 7 of the rectangular wave oscillator 6 becomes low and the switching switch 3,
Although the reset input is not input to the 2-digit binary counter 11 after 5 is switched to the broken line side, the counter 11 continues to operate by the clock of the vertical synchronizing signal 16 and the information that 0 is the first signal is lost. There is no such thing.

Similarly, regarding the VTR reproduction video signal 2, the video signal 2 is connected to the color framing discrimination device 4 while the switching command signal 7 of the rectangular wave oscillator 6 is low, and the counter reset signal 8 obtained from the video signal 2 is 2 The digit binary counter 12 is reset. The 2-digit binary counter 12 uses the vertical synchronizing signal 17 separated from the reproduced video signal 2 through the vertical synchronizing signal separating circuit 10 as an input clock, 0 → 1 → 2 → 3 → 0 → 1 → ...
Therefore, the framing information is not lost even after the changeover switches 3 and 5 are changed over to the solid line side. Two two
The output signals of the digit binary counters 11 and 12 are digital comparator 13
When the counter 11 output and the counter 12 output match, the counter match signal 14 is output. The VTR controller 15 slows down the VTR playback speed a little during the run-up period, and when the counter match signal 14 is output, if the playback speed is set to the normal speed, the color framing of the two signals can be matched at the editing point. it can.

When this embodiment is applied to the framing discrimination device,
The color framing discrimination device 4 is replaced with the framing discrimination device, and the 2-digit binary counters 11 and 12 are replaced with 1-digit binary counters. Further, in a color framing discrimination device of another color system, a 2-digit binary counter is used.
11,12 can be replaced with the same number of counters as the color system has.

In a device using a microcomputer, the outputs of the counters 11 and 12 are directly taken into the VTR control device 15 and the color framing of the two signals is compared to slow down or speed up the VTR playback speed a little. Therefore, the color framing of the two signals can be matched by the phase shift of the video signal of the shortest time and the minimum VTR.

Further, in this case, the rectangular wave oscillator 6 is replaced by the microcomputer output, the input video signal 1 is input to the color framing discrimination device 4, and when the counter reset signal 8 is obtained from the color framing discrimination device 4, the VTR reproduction video is immediately obtained. By switching the changeover switches 3 and 5 so that the signal 2 is input to the color framing discrimination device 4, the color framing of the two signals can be detected in the shortest time.

Also, as the clock input of the 2-digit binary counters 11 and 12,
Although the vertical synchronizing signal is used in the embodiment of FIG. 1, this may be any signal having a period corresponding to the period of framing or color framing. For example, a horizontal synchronizing signal is input and 1/625 The same function can be realized by adding the frequency divider of.

It is also possible to use an oscillator with a constant known frequency, such as an oscillator with a frequency of 50 Hz or an integer multiple of that for the PAL system, as the clock input.In this case, the resulting signal of 50 Hz will deviate from the vertical sync signal. Also, by connecting the playback framing or color framing discrimination device and the counter while the deviation is within the negligible range,
The gap can be kept within a small range and practical problems can be eliminated.

Next, another embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a helical scan type VT in another embodiment.
The tape running figure of R is shown. In FIG. 2, 21 is a magnetic tape, 22 is a rotating cylinder, 23 is a magnetic head, 24 is a capstan, 25 is a pinch roller, 26 is an optical encoder, 27 is a photo interrupter for obtaining an electric signal from the optical encoder 26, 28 to 30 indicate traveling posts.

In a helical scan type VTR, a magnetic head 23 mounted on a rotary cylinder 22 records and reproduces signals. On the other hand, the magnetic tape 21 is driven by a capstan 24 and a pinch roller 25. For example, even when the capstan 24 is stopped, the rotary cylinder 22 continues to rotate, and in this case, since the tape does not run, the magnetic head 23 makes the same video signal proportional to the rotation speed of the rotary cylinder 22. Continue playing at the frequency. In this case, as shown in FIG. 1, using the clock signals for the vertical synchronizing signals 16, 17 counters 11, 12 separated from the reproduced video signal causes inconvenience because framing or color framing is stopped. Therefore, it is necessary to use, as a signal having a cycle corresponding to the cycle of framing or color framing even at an arbitrary reproduction speed, a signal proportional to the reproduction speed of the reproducing apparatus as a clock input. In FIG. 2, a photo interrupter 27, which is a combination of a light emitting diode and a phototransistor, is attached to an optical encoder 26 attached to a capstan 24.
An electric pulse signal proportional to the rotation speed of the capstan 24 is taken out. Since this electric pulse signal is also proportional to the feed amount of the magnetic tape 21, the output signal of the photo interrupter 27 of FIG. 2 is used as the clock input of the counter 12 corresponding to the reproduced video signal 2 of the VTR in FIG. By using a signal obtained by frequency division by an arbitrary numerical value, the framing of a plurality of video signals can be discriminated by one framing or color framing discrimination device while avoiding the inconvenience.

In FIG. 2, the means for extracting the clock signal is as follows.
The magnetic method or the phase signal of the motor can be used when a brushless motor is used as the capstan motor. When light is used, the light from the light emitting diode can be reflected by the optical encoder and received by the phototransistor using a photoreflector. It is also possible to attach the rotation detecting device to, for example, a post in contact with the tape without using the capstan. Also, as shown in Fig. 2, a helical scan type VT
In R, a control pulse is often recorded on the tape as a pulse that is an integral multiple of the vertical synchronizing signal of the recording signal. If the reproduction output of this control pulse is used as the clock input of the counter, , A signal proportional to the playback speed of the playback device can be obtained.

Further, for example, in a magnetic recording / reproducing apparatus using a disc-shaped rotating magnetic sheet, a similar optical encoder is mounted on the rotation axis like the optical encoder attached to the capstan 24 in FIG. The present invention can be realized by obtaining a signal proportional to the reproduction speed of the device and inputting it to the clock of the counter.

FIGS. 3 and 4 show still another embodiment of the present invention in the case of using a microcomputer, for example. FIG. 3 shows a block diagram, and FIG. 4 shows a waveform output. 31 is a first video signal, 32 is a second video signal, 33 is a color framing discrimination device, 34 is a video signal changeover switch, 35 is a framing discrimination signal changeover switch, 36 is a delay circuit, and 37 is a mono-multivibrator. , 38 is a microcomputer device, 39, 4
Reference numerals 0 and 41 denote output signals of the color framing discrimination device 33, the delay circuit 36, and the mono multivibrator 37. When the microcomputer device 38 connects the changeover switches 34 and 35 to the solid line side, the first video signal 31 is inputted to the color framing discrimination device 33, and considering the same color framing as the PAL system shown in FIG. 39 is output. The microcomputer device 38 uses the discrimination signal 39.
Immediately after receiving, the changeover switches 34 and 35 are changed over to the broken line side. Then, the second video signal 32 is input to the color framing discrimination device 33, and the framing discrimination signal 39 of the second video signal 32 is output. On the other hand, the framing discrimination signal 39 of the first video signal detected earlier triggers the delay circuit 36, and the delay signal 40 activates the mono-multivibrator 37 after a fixed time. If the resulting output signal 41 is selected to be high, for example, from the input framing discrimination signal 39 for four vertical synchronization periods or more and five vertical synchronization periods or less, the microcomputer device 38
By comparing the phase of the 41 signal and the phase of the 39 framing determination signal obtained from the second video signal 32, it is possible to determine the framing coincidence of the two signals.

This device can be realized without using a microcomputer. Further, since the microcomputer usually has a built-in timer, the functions corresponding to the delay circuit 36 and the mono-multivibrator 37 can be realized on the microcomputer. As described above, by adding the fixed time delay circuit, the framing or color framing of a plurality of video signals can be discriminated by a single framing or color framing discrimination device.

As described above, according to the present invention, a plurality of video signals are sequentially input to a single framing or color framing discriminating means by using the switching means to discriminate each framing or color framing, and to make the determination. The results can be held by the respective holding means, and thus, the above-mentioned discrimination means, which is required in the same number as a plurality of video input signals, can be achieved by one effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a tape running diagram showing another embodiment of the present invention, and FIG. 3 is a block diagram showing yet another embodiment of the present invention. 4 is the third
FIG. 5 is a waveform diagram of an output signal in the figure, FIG. 5 is a block diagram of a framing discrimination device in a conventional helical scan type editing VTR, FIG. 6 is a concrete block diagram of a main part thereof, and FIG. 7 is a time chart of signals of respective parts. Is. 1 …… VTR input video signal, 2 …… VTR playback video signal,
3 ... video signal selector switch, 4 ... color framing discrimination device, 5 ... reset signal output selector switch, 6
...... Square wave oscillator, 7 ...... Switch command signal, 8 ...... Counter reset signal, 9 ...... First vertical sync signal separation circuit,
10 ... second vertical synchronizing signal separation circuit, 11 ... first two-digit binary counter, 12 ... second two-digit binary counter, 13 ...
Digital comparator, 14 …… Counter match signal, 15 …… VT
R control device, 16, 17 Vertical sync signal, 21 magnetic tape, 22 rotary cylinder, 23 rotary head, 24 capstan, 25 pinch roller, 26 optical encoder, 27 ...... Photo interrupter, 33 ...... Color framing discrimination device, 34 ...... Video signal changeover switch, 35 ...... Framing signal changeover switch, 36 ...... Delay circuit, 37 ......
Mono-multivibrator, 38 ... Microcomputer equipment

Claims (9)

[Claims] 1. A video signal discriminating apparatus for discriminating coincidence by comparing framing or color framing among a plurality of video signals, and discriminating means for discriminating framing or color framing of the video signal, and the discriminating means. Switching means for selectively inputting a plurality of video signals,
The holding means for holding the result of the discrimination by the discriminating means with respect to each video signal and the output signals of the retaining means, or the output signal of the retaining means and the output signal of the discriminating means are compared to determine a match. A counter for resetting the output signal of the discriminating means and counting the electric signal having a cycle corresponding to the framing or color framing cycle of the video signal corresponding thereto; A video signal discriminating apparatus comprising: a delay unit for delaying an output signal of the unit for a predetermined time. 2. The video signal discriminating apparatus according to claim 1, wherein a signal separated from the video signal is used as the electric signal. 3. A video signal discriminating apparatus according to claim 2, wherein a vertical synchronizing signal is used as a signal separated from the video signal. 4. The video signal discrimination according to claim 1, wherein an output signal of an oscillator whose frequency is substantially equal to the frequency of the vertical synchronizing signal of the video signal or an integral multiple thereof is used as the electric signal. apparatus. 5. A plurality of video signals include an input video signal input from the outside and a reproduced video signal reproduced from a recording medium, according to any one of claims 1 to 4.
The video signal discriminating device according to any one of items. 6. An electric signal corresponding to a reproduced video signal,
The video signal discrimination device according to claim 5, wherein a signal proportional to the reproduction speed of the recording medium is used. 7. The recording medium is a magnetic tape, and the signal proportional to the reproduction speed of the recording medium uses a signal proportional to the rotation speed of a capstan for moving the magnetic tape. The video signal discrimination device according to item 6. 8. A magnetic tape for a helical scan VTR having a control track as a recording medium, wherein a control pulse reproduced from the control track is used as a signal proportional to a reproduction speed of the recording medium. The video signal discrimination device according to claim 6. 9. The switching means, after selecting an input video signal to determine framing or color framing,
The video signal discriminating apparatus according to claim 5, wherein the reproduction video signal side is immediately switched.