JPS63207283A - Stripe effect circuit - Google Patents

Abstract

PURPOSE:To interchange band-shaped pictures by providing at least one counter for memory address, at least two latches where data is held, and at least two comparators which compare the value of the counter for memory address with the contents of latches. CONSTITUTION:Data on a data bus B from a CPU is inputted to latches 7-10 to assign them as I/Os or the like of the CPU, and a strobe signal (STRB) is given by an 1/O write instruction or the like of the CPU to hold data H1-H4 in latches 7-10 independently of one another. Gate circuits 11-13 output a horizontal direction key signal S. If the key signal S outputs an image by logical '1' and masks the image by logical '0', a vertical band-shaped image is obtained. Values of data H1-H4 are changed to change bands of an image area. With respect to the vertical direction of the image, a horizontal band- shaped image is obtained by the same method. Further, a lattice-shaped image is obtained by AND between horizontal-direction and vertical-direction key signals.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a digital video effects device in television.

[Conventional technology]

Conventionally, this type of key signal generating circuit has been designed to output uniformly within the edge of the screen as its boundary.

[Problem that the invention seeks to solve]

In the conventional key signal generation circuit described above, the picture appears continuously on the screen, vertically.

It is not possible to obtain the effect of replacing the screen with horizontal bands or rectangles.

SUMMARY OF THE INVENTION An object of the present invention is to provide a stripe effect circuit that can replace screens in a strip-like manner.

[Means for solving problems]

The stripe effect circuit of the present invention includes at least one counter for a memory address in at least one of a horizontal direction and a vertical direction, at least two latches for holding data, and the value of the counter of the memory address and the contents of the latch. and at least two comparators for comparing the two.

〔Example〕

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

FIG. 1 shows an embodiment of the present invention, and this embodiment is intended for a horizontal key signal generation circuit.6 In FIG. 1, 1 is a horizontal memory address counter. , holds multiple bits of data. 2 to 6 are comparators that compare two inputs A and B consisting of multiple bits, and due to the magnitude relationship of inputs A and H, A>B
, outputs a signal where A<B. Numerals 7 to 10 are latches, which input data bus B from the cPU (not shown), are allocated as Ilo, etc. of the CPU, and are given a strobe signal (STRB) by the CPU's I10 write command, etc. to each latch 7 to 10.
10 to independently hold data old to H4. 11-13
is a gate circuit which outputs a horizontal key signal S.

The horizontal memory address counter 1 changes from the beginning to the end of the horizontal video period.

For example, it changes from 0 to 3FF (hexadecimal number, H).

3 Let FFH be called the maximum horizontal address value HMA A<B output, A of comparator 5>
The B output and the A<B output of the comparator 6 are as shown in FIG.

Therefore, the output 11 of the AND of the outputs of comparators 3 and 4
The output 12 of the AND of the comparators 5 and 6 is as shown in FIG. The A<B output of the comparator 2 and the OR output 13 of the outputs 11 and 12 are obtained as shown in FIG. 2, and a horizontal key signal S is obtained. This key signal S is logic '1'
If the image is output at the portion ``0'' and the image is masked at the portion ``0'', an image as shown in FIG. 3 will be obtained. Here, the white part W is the area where the image appears, and the shaded part B
is the area where the image is masked. By changing the values of old to H4, the band of the video area can be changed. An image as shown in FIG. 4 can be obtained by a similar method in the vertical direction of the image. Further, by ANDing the horizontal and vertical key signals, an image as shown in FIG. 5 can be obtained.

Although only a horizontal memory address counter is used in the embodiment, it may be applied to a vertical key signal generation circuit having a vertical memory address counter, or even a horizontal and vertical memory address counter. The present invention may also be applied to a key signal generation circuit having a key signal generation circuit.

〔Effect of the invention〕

As explained above, since the present invention generates a band-shaped key signal, it has the effect of being able to change the screen in a band-like manner by using it for changing the scene of a video.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
Figure 3 shows an example of the image obtained by the circuit in Figure 1. Figure 4 shows the circuit in Figure 1 and the output of the horizontal key which is the final output. A diagram showing an example of an image when a similar method is applied to a vertical key. Figure 5 is a key obtained by ORing the horizontal and vertical key signals shown in Figures 3 and 4. FIG. 3 is a diagram showing an example of a video obtained from a signal. 1...Horizontal memory address counter, 2 to 6.
・2-man power comparator, 7~lO...latch, 1
1 to 13...gate circuit

Claims (1)

[Claims] (1) A video key signal generation circuit includes at least one counter for a memory address in at least one of the horizontal and vertical directions, at least two latches that hold data, and the value of the counter at the memory address. and at least two comparators for comparing the contents of the latches.