JPH04170166A - Video signal switching system - Google Patents

Abstract

PURPOSE:To prevent the transmission of an undesired program from a transmission station at a change in programs by detecting a program change based on a content of a video signal with respect to a timing having a dispersion from the reception of a Q control signal till the change of programs to match the changeover timing of the program of the present station. CONSTITUTION:When a Q control signal in a net cue signal is used to apply changeover control of program transmission, the system is provided with a means 11 delaying a television video signal of an input program source by one field or over and less than two field times, a means 12 comparing two consecutive fields of the television video signal of the input program source and a means 13 detecting it that there is a change in the entire pattern of one field pattern based on the result of comparison. When it is detected that there is a change in the pattern on the entire screen after the reception of the Q control signal, the video signal delayed by one field or over is replaced with other video signal at a succeeding blanking timing. Thus, it is prevented that an undesired program at a change in the program is transmitted.

Description

[Detailed Description of the Invention] [Industrial Application Field] Television broadcasting stations are connected to each other by a television signal transmission line network, and in particular, the switching control of program transmission is performed using the Q control signal of the net queue signal. Related to signal switching method.

[Conventional technology]

When performing this type of conventional switching control, from the station that originated the net cue signal, after superimposing the Q control signal on the video signal to be sent out, (for example) a program from the generating station is terminated after 3 seconds have elapsed. The receiving station was triggered by the received Q control signal and controlled to switch from the generating station's program to the receiving station's program three seconds later.

[Problem to be solved by the invention]

However, from the Q control signal superimposed on the video signal of the station where the net cue signal was generated, the program of the station where the net cue signal was generated actually ended.
The timing until switching to another program varies because the performance of the control device differs depending on the broadcasting station where the broadcast occurs.

Because of this, the time from the Q control signal until the program is switched does not match between the generating station and the receiving station. For this reason, there is a problem in that an unnecessary program may be transmitted at the point where the Q control signal is received and the program switches to the program on the generating station side.

[Means to solve the problem]

The video signal switching method of the present invention sets the timing from receiving the Q control signal, which varies depending on the performance of the control device of the net cue signal generating station, to controlling program switching, to the vertical blanking period of the television video signal. In the video signal switching method, a net cue signal superimposed on a predetermined horizontal scanning period is received, and a Q control signal of the net cue signal is used to control switching of program transmission. means for delaying one field or more and less than two field times; means for comparing two consecutive fields of a television video signal of input program material; and detecting a change in the picture of the entire one field screen from the comparison result. and after receiving the Q control signal, if it is detected that there is a change in the picture pattern on the entire screen, the video signal delayed by one field or more and other video signals are transmitted to the next video signal. This system is configured so that the switching is performed at the blanking timing of the program, thereby preventing unnecessary programs from being transmitted at the transition point between programs.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a television net queue control method according to the present invention.

FIG. 2 is a diagram showing the timing of the video signal.

In the figure, one frame indicates one field time, and the input timing indicates the timing of the video signal input to the line transmission receiving device. The last field of the A program is the A end, and the first field of the B program is the B beginning. Therefore, the program switching timing is at point X.

The control device 1 on the side of the net cue signal generating station receives the video signals c and d of the program material to be sent to the television signal transmission line network.
The switcher 2 is controlled by control lines a and b, and the switching is sent to the net cue signal superimposition device 3. - Net cue signal superimposition control is performed from the power control device 1 to the net cue signal device 3 via a control line, and the video signal i superimposed with the Q control signal is sent to the television signal line transmission transmitting device 5. The control unit W1 performs net cue signal superimposition control and at the same time activates the delay device 4 via a control line f in order to obtain timing for switching the raw video signals c and d. After being activated, the delay device 4 sends a video signal switching timing signal g to the control signal 1 after a predetermined time (for example, 3 seconds) has elapsed. Note that the function of the delay control section described above may be included in the control device 1. The control device 1 performs program switching control using the control lines a and b based on the video signal switching system timing signal g, and the switched video signal e passes through the net cue signal superimposition device 3 to the line transmission transmitting device 5.
sent to. j is a television signal transmission line.

The video signal received by the television signal line transmission receiving device 6 is used as a video signal for broadcast program material from the own station, and also includes a net cue signal detection device 7, a 2-field video signal comparison device 12, and a video signal delay device. Sent to 11. The net cue signal detection bag W7 extracts the net cue signal from the video signal, demodulates the Q control signal m, and sends the output to the control device 8. In order to obtain the video switching timing, the control device 8 receives the Q control signal m and at the same time activates the delay device 9 by the control p, and obtains the switching control signal S after a certain period of time.

The delay time is set several fields shorter than the control time (for example, 3 seconds) of the net queue signal sending station in order to compensate for variations. The two-field video signal comparison device 12 continuously stores the input video signal in the storage device over two fields, compares the signals of each field, and sends the result to the picture switching detector 13 for comparison. As a result, the pattern of the video signal changes rapidly between two fields, and furthermore, it changes over the entire screen, so that a switching point in the pattern is detected. Detection occurs at the timing of X+1 after one field of the switched picture has been stored, as shown in FIG. Video signal delay device 11 has patent registration 01033721
As explained in this issue, an input video signal k with a synchronization timing different from the synchronization signal W sent out by the receiving station is outputted as a video signal with the same phase as the synchronization timing of the receiving station by storage delay, and the output video signal The timing is the output timing shown in FIG. 2, which is delayed by one field or more and less than two fields. In order to obtain the final switcher switching timing Y, the control device 8 once latches the switching control signal S based on the Q control signal and the switching control signal r based on the pattern switching, and sets the AND condition of these signals to the switcher control signal S using the synchronization signal W. A switching timing Y is obtained, a control signal U is sent to the program changeover switcher 10, and the broadcast program video signal from the local station is switched from the program video signal (2) from the net queue signal generating station to the program video signal 1 within the local station. Note that a configuration in which the function of the delay control section described above is included in the control device 8 is also conceivable.

Figure 3 is a diagram showing the control timing of each part, where ① is the timing on the side of the net queue generating station, and the video signal C sent to the receiving station is a video signal that is not needed by the receiving station at the program end timing 2''. d.The Q control signal is superimposed just before the switching timing "a time predetermined by the second part".■ is the timing on the receiving station side, and the Q control signal is superimposed in advance after receiving the Q control signal. After a predetermined delay time elapses, the received video signal k is switched to the program video signal 1 within the own station at the timing chart ho. However, since the characteristics of the control devices at the sending stations are not unified, the timing diagrams will vary.Therefore, as shown by
During this period, unnecessary video d is transmitted to the receiving station.

In the present invention, the content of the received video signal is checked to obtain the timing "2", and the unnecessary video d is not transmitted by setting the time "c" to 0.

〔Effect of the invention〕

As explained above, according to the present invention, the timing from when a Q control signal, which varies depending on the broadcasting station, is received until the program is switched is detected based on the content of the video signal, and the switching point is detected based on the content of the video signal. By matching the switching timing of the program to the switching point, it is possible to prevent unnecessary programs from being transmitted from the transmitting station at the program switching point.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the net queue control method according to the present invention, Fig. 2 is a timing diagram of each field at the picture switching point to explain Fig. 1, and Fig. 3 is an unnecessary screen. FIG. 2 is a timing diagram illustrating the reason why is sent. DESCRIPTION OF SYMBOLS 1... Control device on the sending station side, 2... Video switcher for program switching on the sending station side, 3... Net cue signal superimposition device, 4... Q control delay device on the sending station side, 5・
... Television line transmission transmitting device, 6... Television line transmission receiving device, 7... Net cue signal detection device, 8... Control device on the receiving station side, 9... Q on the receiving station side Program switching control delay device using control signals, 10.
...Video switcher for program switching on the receiving station side, 11.
...1 field or more, less than 2 fields video delay device, 12...2 field video signal comparison device, 13
...Picture switching detection device.

Claims (1)

[Claims] In a video signal switching method that receives a net cue signal superimposed on a horizontal scanning period with a determined vertical blanking period of a television video signal, and controls switching of program transmission using a Q control signal of the net cue signal. , means for delaying the television video signal of the input program material by one field or more and less than two field times, means for mutually comparing the video signals of two consecutive fields of the television video signal of the input program material, and a comparison result. means for detecting that there has been a change in the pattern of the entire one-field screen from A video signal switching method characterized in that a video signal delayed by one field or more and another video signal are switched at the next blanking timing.