JPH065918B2 - Video mixing amplifier - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television video mixing amplifier, and more particularly to a video mixing amplifier for performing wipe and border wipe.

[Conventional technology]

An example of a conventional video mixing amplifier of this type is shown in FIG. 4 and explained. In the figure, A, B and BC are input signals which are video signals, S ₁ is a wipe signal, S ₂ is a border signal, and S ₄ is It is an output video signal.

Reference numeral 11 denotes a key signal processing circuit that receives the wipe signal S ₁ and the border signal S ₂ and processes the key signal.
Reference numerals 3 and 14 denote first, second, and third multiplication circuits that receive the input signals A, B, and BC and perform multiplication. The first, second, and third multiplication circuits perform the key signals processed by the key signal processing circuit 11. 3 multiplication circuit
Keying is performed with 12, 13, and 14, and the first to
Wiping and border wiping are performed by synthesizing the three outputs of the third multiplication circuits 12 to 14, and the output video signal S ₄ is obtained at the output side of the addition circuit 15.

The waveforms of the output key signal, the input wipe signal, and the input border signal of the key signal processing circuit 11 are shown in FIGS. 5 and 6.

FIG. 5 shows the case of border wipe, and FIG. 6 shows the case of wipe.

Then, (a) shows an input wipe signal, (b) an input border signal, (c) a key signal for the first multiplication circuit 12, (d) a key signal for the second multiplication circuit 13, and (e) ) Indicates the key signal for the third multiplication circuit 14, respectively.

[Problems to be solved by the invention]

In the above-mentioned conventional video mixing amplifier, the third video amplifier is used for wiping.
There is a problem that I am using the multiplication circuit of
When obtaining the key signals for the first and second multiplication circuits, there is a problem that the key signal processing circuit needs to calculate the wipe signal and the border signal.

[Means for solving problems]

The video mixing amplifier according to the present invention controls a switching circuit which receives a plurality of video signals as input and switches these signals, and a wipe signal, a border signal and a border wipe control signal as input and performs processing of a key signal. The key signal processing circuit for performing, the first multiplication circuit and the second multiplication circuit for receiving and multiplying the signals from the switching circuit and the key signal processing circuit, and the outputs of the first and second multiplication circuits are added. And an adder circuit for obtaining an output video signal.

[Action]

In the present invention, attention is paid to the fact that the wipe boundary is keyed by the border signal and does not appear on the screen when the border wipe is performed.
Two screens are combined, and at the time of border wipe, the switching circuit combines the two screens, and the multiplication circuit processes the border portion.

〔Example〕

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a video mixing amplifier according to the present invention.

In FIG. 1, the same reference numerals as those in FIG. 4 indicate corresponding parts, and 1 is a switching circuit for inputting a plurality of input signals A, B and BC which are video signals and switching them, and 2 is a wipe signal S. ₁ and border signal S ₂ and border wipe control signal S
_A key signal processing circuit for controlling the switching circuit 1 with ₂ as an input and for processing a key signal, and 3 and 4 are first multiplications for receiving and multiplying signals from the switching circuit 1 and the key signal processing circuit 2. The circuit and the second multiplication circuit 5 are addition circuits for adding the outputs of the first and second multiplication circuits 3 and ₄ to obtain an output video signal S ₄ .

The operation of the embodiment shown in FIG. 1 will be described below with reference to FIGS.

FIG. 2 and FIG. 3 are diagrams showing signal waveforms of respective parts used in the explanation of the operation of FIG. FIG. 2 shows a wipe operation, and FIG. 3 shows a border wipe operation. In FIG. 2, (a) shows an input wipe signal, (b) an input border signal, (c) a key signal for the first multiplication circuit 3, and (d) a second multiplication circuit 4. Shows key signal,
In FIG. 3, (a) is an input wipe signal, (b) is an input border signal, (c) is a switching signal for switching the video signal input to the first multiplication circuit 3, and (d) is the first multiplication signal. The key signal for the circuit 3 and (e) show the key signal for the second multiplication circuit 4, respectively.

First, the operation of each part when performing a wipe will be described with reference to FIG.

The border wipe control signal S ₃ is given to the key signal processing circuit 2 to control the border wipe OFF, and the key signal processing circuit 2 controls the switching circuit 1 to input the input signal A and the second signal to the first multiplication circuit 3. Control is performed so that the input signal B is output to each of the multiplication circuits 4. The key signal processing circuit 2 receives the wipe signal S ₁ as an input and outputs the first multiplication circuit 3
To the second multiplying circuit 4 and the inversion of the wipe signal to the second multiplying circuit 4 (see FIGS. 2C and 2D). And this first
In the second multiplication circuits 3 and 4, keying is performed with these key signals, and the addition circuit 5 adds the signals to wipe the input signal A and the input signal B (second).
See figure).

Next, the operation at the time of border wipe will be described with reference to FIG.

First, under the control of border wipe ON, the key signal processing circuit 2 uses the wipe signal S ₁ to generate a switching signal for switching the video signal input to the multiplication circuit. That is, the input video signal of the first multiplication circuit 3 is the wipe signal S
_The input signal A and the input signal B are switched at the boundary of ₁ , and the input video signal of the second multiplication circuit 4 is the input signal B.
It becomes C (border color signal).

Next, in the first multiplication circuit 3, the video signal in which the input signal A and the input signal B are switched and the key signal obtained by inverting the border signal are multiplied. Then, in the second multiplication circuit 4, the border color signal (input signal BC) is multiplied by the border signal S ₂ . Then, by adding these two results in the adder circuit 5, the input signal A and the input signal B are added.
You can get a screen with border wipe.

In the above embodiment, the input signal A and the input signal B are
However, the present invention is not limited to this, and a wipe signal for switching is added to the key signal processing circuit 2 and
By adding an input signal to the switching circuit 1, it is possible to switch the input signals, which are a plurality of video signals, and add a border thereto.

〔The invention's effect〕

As described above, according to the present invention, since two screens are performed by using the multiplication circuit at the time of wiping, soft wiping is also possible, and at the time of border wiping, it is possible to perform two screens by the switching circuit.
By combining two screens and processing the border portion by the multiplication circuit, the multiplication circuit can perform two circuits, and the addition circuit can perform border wipe by two-input addition. Therefore, the practical effect is extremely large.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a video mixing amplifier according to the present invention, FIGS. 2 and 3 are waveform diagrams showing waveforms of signals of respective parts used for explanation of operation of FIG. 1, and FIG. FIG. 5 is a block diagram showing an example of a video mixing amplifier, and FIG. 5 and FIG. 6 are waveform diagrams showing waveforms of signals of respective parts used in the explanation of the operation in FIG. 1 ... Switching circuit, 2 ... Key signal processing circuit, 3, 4 ...
Multiplier circuit, 5 ... Adder circuit.

Claims (1)

[Claims] 1. A switching circuit for inputting a plurality of video signals and switching these signals, and a key signal processing for controlling the switching circuit by inputting a wipe signal, a border signal and a border wipe signal and processing a key signal. A circuit, a first multiplication circuit and a second multiplication circuit for receiving and multiplying signals from the switching circuit and the key signal processing circuit, and outputs of the first and second multiplication circuits and output video signal An image mixing amplifier comprising: