JPH06165030A - Video signal switching circuit - Google Patents

Abstract

PURPOSE:To switch display pictures while providing any special effect such as oozing out the display picture of a selected video signal from a currently displayed picture when switching the display pictures. CONSTITUTION:This circuit is composed of a line memory 4 for writing the scanning line of a video signal (a), a line memory 8 for writing the scanning line of a video signal (b), switcher 10 for switching and outputting the scanning lines read out of the line memories 4 and 8, and control part 9 for outputting a control signal to control write and read to the line memories 4 and 8 and to change over the switcher 10 by counting the number of scanning lines and when a video switching signal is inputted to this control part 9, the video signals are switched while changing a ratio between the scanning lines of video signals (a) and (b) outputted from the switcher 10 at a prescribed rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal switching circuit used in video equipment.

[0002]

2. Description of the Related Art In a conventional video signal switching circuit, a desired signal is selected for a plurality of video signal inputs and the screen is switched instantaneously, or the screen is switched by a fade-out / fade-in method. Was there.

[0003]

SUMMARY OF THE INVENTION The present invention provides a display screen with a special effect such that the display screen of a video signal selected from the currently displayed screen is blurred when the display screen is switched. It is an object of the present invention to provide a video signal switching circuit capable of switching the video signal.

[0004]

As shown in FIG. 1, a line memory 4 for writing a scanning line of a video signal (a), a line memory 8 for writing a scanning line of a video signal (b), a line memory 4 and A switch 10 for switching and outputting the scanning lines read from the line memory 8, and the line memory 4
And a control unit 9 which controls writing and reading to and from the line memory 8 and outputs a control signal for counting the number of scanning lines and switching the switching unit 10. The video switching signal is input to the control unit 9. In this case, the ratio of the scanning lines of the video signal (a) and the video signal (b) output from the switch 10 is changed at a predetermined ratio to switch the video signal.

[0005]

In the present invention, the line memory 4 is used when the video signal is switched.
Also, the scanning line written in the line memory 8 is read and the switch 10 is switched to alternately output the video signal a and the video signal b. For example, as shown in FIG. 2, the state before switching (A) diagram Therefore, as shown in FIG. 6B, one video signal b is output every nine video signals a.
Further, as shown in FIG. 7C, one video signal b is output for every five video signals a, and similarly, the video signals a are sequentially changed from FIG. By changing the scanning line ratio of the video signal b and the video signal b at a predetermined ratio, the video signal a is switched to the video signal b through a plurality of steps. It is possible to switch the display screens with a special effect such that the display screen of the selected video signal is blurred.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an electric circuit block diagram of a video signal switching circuit showing an embodiment of the present invention. The video signal a input via the input terminal 1 and the video signal b input via the input terminal 5 are input to the phase circuits 2 and 6, respectively, and the phase circuits 2 and 6 have the same reference signal. By comparing the phase using the video signal a and the video signal b
The video signal a is input to the A / D converter 3, and the video signal b is input to the A / D converter 7. The A / D converter 3 converts the video signal a into a digital signal and outputs the digital signal, which is input to the line memory 4, and the A / D converter 7 converts the video signal b into a digital signal and outputs the digital signal. Are typing in. A FIFO (FIRST In FIRST) is used as the line memory 4 and the line memory 8.
Out) type memory is used, and the line memory 4 writes and reads the scanning line of the video signal a by the clock pulse input from the control unit 9 and outputs the scanning line to the switch 10.
The line memory 8 writes and reads the scanning line of the video signal b, outputs the scanning line, and inputs the scanning line to the switch 10.

The switching device 10 switches between the two inputs in response to a switching signal input from the control unit 9 and outputs them, which are input to the D / A converter 11. The D / A converter 11 converts the input into an analog signal and outputs the analog signal from the output terminal 12, and the screen is displayed on a CRT or the like based on the output. As the control unit 9, for example, a microcomputer is used,
It is assumed that a video signal switching signal is input to the control unit 9 by using an operation unit provided in the device or a remote controller. The control unit 9 refers to the previous switching signal of the switching unit 10 stored in the internal storage unit, determines the video signal output from the switching unit 10, and determines that the video signal is, for example, the video signal a. Then, the number of scanning lines of the video signal a is counted by the counter in the control unit 9, the switch 10 is switched, the scanning lines of the video signal b are output, and the ratio of the scanning lines to be output is changed at a predetermined ratio. The video signal is switched accordingly.

2A to 2F are scanning line diagrams showing an example of the switching operation of the video signal switching circuit of the present invention. The standard system of the current television is about 60 as the field frequency.
Using Hz, two fields form one frame, and one frame displays 525 scanning lines. FIG. 9A shows a state before switching the video signal, the screen display is only the scanning line of the video signal a, and the ratio of the video signal a and the video signal b is 1: 0. (B)
The figure shows the switching state of the first stage, and the control unit 9 controls the video signal a.
Of the scanning lines of the video signal a, for example, after counting the ninth scanning line of the video signal a, the switching unit 10 is switched by the switching signal from the control unit 9 to output the tenth scanning line of the video signal b. And switch the switch 10 again,
The scanning line of the video signal a is output as the eleventh line, the ratio of the video signal a to the video signal b is set to 9: 1, and the switching device 10 outputs the scan line. To the switching state.

FIG. 3C shows the switching state at the second stage. When the control unit 9 counts the number of scanning lines of the video signal a, for example, when the fifth scanning line of the video signal a is counted, the control unit Switching the switch 10 by the switching signal from 9,
The sixth scan line of the video signal b is output, and the switch 1
By switching 0, the scanning line of the video signal a is output as the seventh line, and the ratio of the video signal a and the video signal b is set to 5: 1 so that it is output from the switch 10.
After continuing for 6 frames, the next switching state is set. (D)
The figure shows the switching state of the third stage, and the control unit 9 controls the video signal a.
Of the scanning lines of the video signal a, for example, the third scanning line of the video signal a is counted, the switching device 10 is switched by the switching signal from the control unit 9, and the fourth scanning line of the video signal b is output. Then, the switching device 10 is switched again and 5
The scanning line of the video signal a is output as the main output, the ratio of the video signal a and the video signal b is set to 3: 1 and the switching device 10 outputs the scan line, and after continuing for 6 frames, the next Put in the switching state.

FIG. 6E shows the switching state at the fourth stage. When the control section 9 counts the number of scanning lines of the video signal a, for example, when the second scanning line of the video signal a is counted, the control section Switching the switch 10 by the switching signal from 9,
The third scan line of the video signal b is output, and the switch 1
By switching 0, the scanning line of the video signal a is output as the fourth line, and the ratio of the video signal a and the video signal b is set to 2: 1 so that the switching device 10 outputs the scanning line.
After continuing for 6 frames, the next switching state is set. (F)
The figure shows the switching state of the fifth stage, and the control unit 9 controls the video signal a.
Of the scanning lines of the video signal a, for example, the first scanning line of the video signal a is counted, the switching device 10 is switched by the switching signal from the control unit 9, and the second scanning line of the video signal b is output. Then, the switching device 10 is switched again to output the third scanning line of the video signal a, and the switching device 10 outputs the video signal a and the video signal b at a ratio of 1: 1. Then, after continuing for 6 frames, the next switching state is set.

As the sixth stage switching state, the video signal b
Screen display of only the scanning lines of the video signal a and the video signal b
The ratio is set to 0: 1, and the switching operation of the video signal switching circuit ends. Therefore, it is possible to switch the display screen with a special effect such that the display screen of the video signal selected from the currently displayed screen is blurred. In addition,
In the example shown in FIG. 2, the ratio of the scanning lines output from the video signal a and the video signal b is changed every 6 frames so that the switching is performed in 5 steps, and the time from the start of switching to the end of switching is 30 in total. Since the frame is switched, the switching time is 1 second. Different values may be used as the number of frames, the number of switching steps, and the switching time so that a special effect such that the display screen of the selected video signal becomes blurred.

[0012]

As described above, according to the present invention,
It is possible to provide a video signal switching circuit capable of switching the display screen with a special effect such that the switching screen is blurred from the currently displayed screen.

[Brief description of drawings]

FIG. 1 is an electric circuit block diagram of a video signal switching circuit showing an embodiment of the present invention.

2A to 2F are scanning line diagrams showing an example of a switching operation of a video signal switching circuit of the present invention.

[Explanation of symbols]

 1 Input Terminal 2 Phase Circuit 3 A / D Converter 4 Memory 5 Input Terminal 6 Phase Circuit 7 A / D Converter 8 Memory 9 Control Section 10 Switcher 11 D / A Converter 12 Output Terminal

Claims (3)

[Claims] 1. A first line memory for writing a scanning line of a first video signal, a second line memory for writing a scanning line of a second video signal, and a scanning line read from the first line memory and the second line memory. And a controller for controlling writing and reading to and from the first line memory and the second line memory and for outputting a control signal for counting the number of scanning lines and switching the switch. When a video switching signal is input to the control unit, the ratio of the scanning lines of the first video signal and the second video signal output from the switching device is changed at a predetermined ratio,
A video signal switching circuit characterized by switching video signals. 2. A phase circuit for matching the phases of the input circuits of the first video signal and the second video signal is provided to input the video signals to the first line memory and the second line memory, respectively. The video signal switching circuit according to claim 1, which is characterized in that. 3. The video signal is switched by changing the ratio of the scanning lines of the first video signal and the second video signal output from the switching device at a predetermined ratio for every plurality of frames. 1. The video signal switching circuit described in 1.