JPS59157881A - Automatic program searching device of video tape - Google Patents

Abstract

PURPOSE:To attain the automatic program searching at a desired position in a simple and assured way without performing previously a complicated operation, by comparing a reproduction mark signal with a reference signal to control the stop of reproduction. CONSTITUTION:A color bar of a video tape is reproduced into a reproduction mark signal and compared with a reference signal by a differential amplifier 1. The output of a waveform shaping circuit 3 is set at a low level with the coincidence between the inputs of both signals. At the same time, the output of a gate 5 is kept at a low level. As a result, a gate 7 is closed and the set output of a timer 6 is cut off. Then the reproduction of the tape is continued, and the output of the amplifier 1 is inverted to a high level by the reproduction output of a credit part. Then the gate 7 is opened with a vertical synchronizing signal supplied from the credit part via a gate 5 and a sampling pulse generator 4. Thus the set output of the timer 6 is delivered as a reproduction stop signal, and at the same time the timer 6 is reset to perform the program searching. In such a constitution, the program searching is automatically performed without having any pre-operation such as recording of a time code, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic video tape cueing device, and more particularly to a device that can automatically stop a video tape at a predetermined image position when playing the video tape.

In general, at television broadcasting stations (c), in order to broadcast a program recorded on a videotape, the videotape is held at a predetermined image position of the first position where the program starts, so-called ``cueing''. Conventionally, in order to perform this kind of cueing, it was necessary to search for this position manually while watching the playback screen of the videotape, or to record a cue signal in the audio trunk of the videotape and start the tape. When the video tape is played back, it can be automatically notified that the tape has arrived at that position, or even a time code signal can be recorded on the video tape in advance and the time code signal read out during playback can be viewed. We are trying to make it easier to cue up.

However, manual operation as described above generally takes time to set up, and even with the latter, the cue
It is necessary to record signals, time code signals, etc. on videotape in advance, which poses problems such as so-called advance work is required.

The present invention has been made in view of the above circumstances, and does not require any special operations for cueing, and automatically detects when the tape has reached a predetermined image position when reading and playing the tape. It is an object of the present invention to provide an automatic videotape cueing device that can cue the videotape to a desired image position by visually checking and stopping the playback of the tape.

One embodiment will be described below with reference to the accompanying drawings.

Generally, video tapes used in broadcasting stations at broadcasting stations have an image pattern as shown in FIG. 1, for example.

This videotape has a portion called a winding margin at the leading end of the tape, and this portion is the portion that is first wound onto the winding reel when the videotape is played back.

Next, there is a part where a video adjustment signal of about 60 seconds length is recorded, but this adjustment signal is a signal for electrically adjusting the video tape player to the optimum state during playback, and is usually A color par signal as shown in FIG. 3 is often used. Furthermore, after the adjustment signal, there is a credit signal section in which the program name, broadcast date, etc. are written, a blank section before the introduction of the program, and a program section for broadcasting.

In the image pattern on the videotape shown in Figure 1, the length of the credit section and the blank section is exactly 15
Since the start of the videotape is determined to be 15 seconds before the start of the program, the start position of the videotape is usually the end position of the adjustment signal.

In particular, in the embodiment described later, automatic cueing is possible by using the adjustment signal as a mark signal.

FIG. 2 is a block diagram showing the schematic configuration of this embodiment.

In FIG. 2, l is a differential amplifier that compares the video signal with a color par signal that serves as a reference. When playing a videotape, the reproduced video signal A and the color par signal B that serves as a reference signal are It is designed to be input synchronously.

2 is a low-pass filter that removes high frequency components from the output signal of the differential amplifier l.

3 is a waveform shaping circuit, which includes a positive clamp circuit to make the output of the differential amplifier 1 higher than the ground potential in both positive and negative cases, and a positive clamp circuit to make the signal from this clamp circuit a perfect rectangular wave. The output from the filter 2 is output as a shaped rectangular wave in order to facilitate signal processing at a later stage.

On the other hand, 4 is a sampling pulse generator provided to extract a portion within a certain range from the video signal for each field, and a vertical synchronizing signal is inputted for each field of the video signal to generate sampling pulses of a predetermined width. It is supposed to occur.

In this embodiment, due to the operation of the sampling pulse generator 4, even if there are three types of image patterns of the color par signal serving as the reference signal as shown in aIb1cVC in FIG. Since only the image can be extracted, any image pattern can be used as the reference signal.

Reference numeral 5 denotes a first gate circuit, into which the extraction pulse is input as a gate signal.

The output of this gate circuit 5 is inputted to a quimaro and a second gate circuit 7, and the quimaro is set when the output of the gate circuit 5 is at the rLJ level, and reset when the output from the gate circuit 5 is at the rHJ level.

Further, this timer 6 is connected to a second gate circuit 7 so that when a set signal is input and a sum of seconds has elapsed, the output is inverted from ILJ to "H" level and opens a second gate circuit 7, which will be described later. There is.

Note that the setting time of the timer 6 is 20 seconds in the embodiment, but it can be set arbitrarily as long as it is within the time when the video signal A is stably supplied.

The second gate circuit 7 is connected to a video tape reproducing machine, and immediately stops playing the video tape when an "H" level signal is output.

Next, the operating procedure of the apparatus of the present invention will be explained based on the above-mentioned embodiment.

When the video signal A recorded on the videotape is read out in synchronization with the color par signal B, the videotape starts from the reeling margin and goes from color bar to credit to blank to program as shown in Figure 1. In this way, the image positions are changed one after another.

Therefore, if we consider the case where a color bar image on a videotape is being played back, the input of the differential amplifier circuit l is A'=B
Therefore, even if a sampling pulse is output for each field of the video signal and the first gate circuit 5 is opened, the output of the waveform shaping circuit 3 is at the rLJ level, in other words, there is no pulse. Therefore, the output of the first gate circuit 5 is r
It becomes Lj.

As a result, the timer 6 is set, but the second gate circuit 7 is closed, so that the videotape continues to be played.

Then, the following logical judgments are made continuously, and when 20 rc' elapses after Kuimaro's cent, the output of the timer 6 is inverted to the "H" level (1), and the second gate circuit 7 is opened. It will be done.

However, at this point, since the video signal A is at the color par image position, the output of the first gate circuit 5 still holds the rLJ level, and the output of the second gate circuit 7 also reaches rLJ. Since it holds
Playback of the videotape will continue.

Then, as the videotape continues to play and enters the credit picture position, the input of differential amplifier 1 is A4=B(A)B
orA(B), so the vertical synchronizing signal is extracted on the first field screen of the credit image and input to the pulse generator 4, and at the same time the extracted pulse is input to the first gate circuit 5, the second A reproduction stop pulse of rHJ level is outputted from the gate circuit 7, and at the same time, timer 6 is reset.

As a result, the playback of the videotape is stopped at the first frame of the credit image after the end of the reproduced color par image, and cueing is performed.

As can be understood from the above detailed description, the device of the present invention does not require special preliminary work for cueing, and can automatically stop at a predetermined image position when playing a videotape. It is very useful because it is possible.

In this embodiment, color par, which is required to be recorded on professional video tapes, is used as a mark signal, but it is also possible to record a predetermined signal as a mark signal within the blanking period of the video signal. It goes without saying that the same effect can be obtained.

41't. A device for generating a reference signal of the same pattern to be compared with the mark signal is built into the device of the present invention.

Alternatively, the signal may be input from a reference signal generator within the broadcasting station separately from the apparatus of the present invention.

It goes without saying that if a delay queamer circuit is connected after the second gate circuit 7, automatic cueing at any time position is possible.

[Brief explanation of drawings]

Figure 1 shows the theory (7) of videotape image patterns;
FIG. 4 is a waveform diagram illustrating the control principle in the apparatus of the present invention.

Claims (1)

[Claims] 1. An automatic videotape cue device characterized in that, when playing a videotape, a mark signal recorded in advance on the videotape is compared with a reference signal, and the playback of the videotape is stopped.