JP2973228B2 - Video signal switching method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a video signal switching system in which television broadcasting stations are connected to each other via a television signal transmission network, and switching control of program transmission is performed by a Q control signal.

[Conventional technology]

When performing this type of conventional switching control, a program from the generating station is terminated when (for example) 3 seconds have elapsed after the Q control signal is superimposed on the video signal, and the received Q control signal is transmitted to the receiving station. Three seconds after the trigger, control was performed to switch from the program on the generating station to the program on the receiving station.

[Problems to be solved by the invention]

However, the timing from the Q control signal superimposed on the video signal of the generating station to the end of the program of the generating station and the switching to another program varies because the performance of the control device differs for each broadcasting station. There is. For this reason, the time from when the Q control signal is switched to the program is different between the generating station and the receiving station. For this reason, there has been a problem that an unnecessary program may be transmitted on the receiving station side between the switching of the program on the generating station side and the switching of the program on the receiving station side.

[Means for solving the problem]

The video signal switching method according to the present invention includes a Q control signal superimposing means for superimposing a Q control signal on a plurality of material video signals at an arbitrary timing, and superimposing the Q control signal on a selected material video signal. A video signal delay means for providing, at a transmitting station side, first material video switching control means for switching to another material video signal after a lapse of a predetermined time from the time of transmission, and for delaying the received video signal by at least one field and less than a field Q control signal extracting means for extracting a superimposed Q control signal from the received video signal; and a switching control signal output for outputting the extracted Q control signal with a delay slightly shorter than the predetermined time. Means for sequentially comparing two consecutive fields of the received video signal, and detecting a moment when a change occurs in the picture of the entire one-field screen from the comparison result. A screen change detecting means for outputting a screen change signal, and when both the switching control signal and the screen change signal are detected, the local station detects a change in the received video signal from the received video signal delayed by the time of one field or more and less than two fields. A second material video switching means for controlling to switch to a material video signal is provided on the receiving station side so as to prevent unnecessary programs from being transmitted at program switching.

〔Example〕

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

FIG. 1 is a block diagram showing one embodiment of a television video switching system according to the present invention.

FIG. 2 is a diagram showing the timing of a video signal. In the figure, one frame indicates one field time, and the timing of the video signal input to the line transmission receiver is indicated by the input timing. The last field of program A is A end, and B is
The first field of the program starts at B. Therefore, the program switching timing is at point X.

The control device 1 on the generating station side switches the video signals c and d of the material of the program to be transmitted to the television signal transmission network by using the control lines a and b.
To control the switcher and send it to the Q control signal superimposing device 3. On the other hand, from the control device 1 to the Q control signal superimposing device 3
Is superposed on the control line h, and the video signal i on which the Q control signal is superimposed is sent to the television signal line transmission / transmission device 5. The control device 1 activates the delay device 4 via the control line f in order to obtain the timing for switching the video signals c and d of the material at the same time as performing the Q control signal superimposition control. After a predetermined time (for example, 3 seconds) elapses after the delay device 4 is activated, the delay device 4 sends a video signal switching timing signal g to the control signal 1. Note that a configuration in which the function of the delay control unit described above is included in the control device 1 may be used. The control device 1 controls program switching by the control lines a and b based on the video signal switching timing signal g, and sends the switched video signal c to the line transmission transmitting device 5 through the Q control signal superimposing device 3. Can be j is a television signal transmission line.

The video signal k received by the line transmission receiving device 6 is used as a video signal of a broadcast program material from the own station, and is also transmitted to a Q control signal detecting device 7, a two-field video signal comparing device 12, and a video signal delay device 11. Can be The Q control signal detection device 7 extracts and demodulates the Q control signal from the video signal k, and sends the output m to the control device 8. The control device 8 receives the Q control signal m and activates the delay device 9 by the control p at the same time as obtaining the video switching timing, and obtains the switching control signal s after a predetermined time. The delay time is controlled by the Q control signal transmitting station control time (for example, 3
Seconds) shorter than a few fields. 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, sends the result to the picture switching eye detector 13, and outputs the comparison result. Since the pattern of the video signal changes rapidly between the two fields and changes over the entire screen, the switching point of the pattern is detected. The detection is shown in FIG. This is the timing of X + 1 after the switched pattern is stored for one field. As described in Japanese Patent No. 0103721, the video signal delay device 11 is adapted to input video signal k having a synchronization timing different from the synchronization signal w transmitted from the receiving station.
To output a video signal having the same phase as the synchronization timing of the receiving station due to the storage delay. The timing of the output video signal is the output timing shown in FIG. 2 and is delayed by one field or more and less than two fields. The controller 8 once latches the final switcher switching control signal s and the switching control signal r at the pattern switching point, and obtains the switcher switching timing Y by the AND signal of these signals using the synchronization signal w to obtain the program switching switcher 10.
, And switches the broadcast program video signal from the local station from the video signal v from the Q control signal generating station to the local program video signal l. Note that a configuration in which the function of the above-described delay control unit is included in the control device 8 is also conceivable.

FIG. 3 is a diagram showing the control timing of each section, where is the timing on the side of the Q control signal generating station, and the video signal c to be transmitted to the receiving station is the program end timing "d", which is not required at the receiving station. Switching to video signal d. The Q control signal h is superimposed just before the time “a” predetermined by the switching timing “d”. Is the timing on the receiving station side, and after a delay of a predetermined time “b” after the reception of the Q control signal h, the video signal k received at the timing “e” is changed to the program video signal l in the own station. Perform a switch. However, since the characteristics of the control devices of the sending stations are not unified, “A” varies. Therefore, as shown by, unnecessary video d is transmitted from the receiving station during the time "c" obtained by subtracting the time "a" from the time "b".

In the present invention, the timing "d" is obtained by confirming the content of the received video signal, and the time "c" is set to "o" so that the unnecessary video d is not transmitted.

〔The invention's effect〕

As described above, according to the present invention, the timing from the reception of a Q control signal having a variation by the broadcasting station to the switching of the program is determined based on the content of the video signal, and the switching face is detected. By making the switching timing coincide with the switching timing, unnecessary programs can be prevented from being transmitted from the transmitting station at the switching timing of the program.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a video signal switching system according to the present invention. FIG. 2 is a timing chart of picture switching at a field unit for explaining FIG. 1. FIG. FIG. 7 is a timing chart for explaining the cause of the transmission of the "." 1. Control device on the transmitting station side 2. Video switcher for program switching on the transmitting station side 3 ... Q control signal superimposing device 4,
... Q control delay device on the transmitting station side, 5... Line transmission transmitting device, 6... Line transmission receiving device, 7... Q control signal detecting device, 8. Q at the receiving station
Program switching control delay device by control signal, 10 ... Video switcher for program switching at receiving station side, 11 ... Video delay device from one field to less than two fields, 12 ... 2 field video signal comparison device, 13 ... Picture switching Eye detection device.

Claims (1)

(57) [Claims] 1. A Q control signal superimposing means for superimposing a Q control signal on a plurality of material video signals at an arbitrary timing, and a predetermined time from the time when the Q control signal is superimposed on a selected material video signal and transmitted. A first material video switching control means for switching to another material video signal after a lapse of time is provided on the transmitting station side, a video signal delay means for delaying a received video signal by one or more fields and less than a field; Q control signal extraction means for extracting a superimposed Q control signal from a video signal; switching control signal output means for outputting the extracted Q control signal with a delay slightly shorter than the predetermined time; Two consecutive fields of the video signal are sequentially compared, and from the comparison result, the moment when a change occurs in the pattern of the entire one-field screen is detected, and a screen change signal is output. Screen change detection means, when both the switching control signal and the screen change signal are detected,
Video signal switching, wherein the receiving station includes second material video switching means for controlling switching from the received video signal delayed by the time of one field or more and less than two fields to the material video signal of the own station. method.