JPH0516711B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a video special effect circuit used in an editing device of a broadcasting station, and more particularly to a video special effect circuit capable of producing mix swipes.

Background Art and Problems When wiping a second image over a first image, the first and second video signals are mixed at an appropriate mixing ratio to form a composite video signal, and this signal is added to the section to be wiped. A mix-swipe type video special effect circuit that mixes a first video and a second video only during the wipe section by supplying a composite video signal is already known.

This conventional mix-swipe type video special effects circuit is configured such that the mixing ratio can be changed only during the wipe period, and the wipe period, that is, the insertion position of the second image to be wiped into the first image is fixed. There is. For this reason, for example, when a present scene and a past scene are superimposed, such as in a flashback scene, we not only change the mixing ratio, but also express the scene in an image that imagines the passage of time. It is preferable to make it possible.

In conventional video special effect circuits, the position to be wiped is fixed, so it is difficult to obtain sufficient video effects for such flashback scenes.

Purpose of the Invention Therefore, in this invention, the first image and the second image are configured so that they can be mixed at an appropriate mixing ratio, and the position to be wiped can also be changed over time. This paper proposes a special effects circuit.

Summary of the Invention Therefore, in the present invention, there is provided a mixing circuit that mixes a first video signal and a second video signal to obtain a composite video signal; It consists of a forming circuit that obtains a mix control pulse that can vary the signal mixing ratio and wipe position, and this forming circuit is supplied with a horizontal or vertical cycle wipe signal and a variable reference voltage that allows the wipe position to be varied. It is configured as follows.

Embodiment Next, an example of a video special effect circuit according to the present invention will be explained in detail with reference to FIG. 1 and subsequent figures.

In FIG. 1, reference numeral 10 indicates a video special effect circuit according to the present invention, which is composed of a mixing circuit 20 and a mix control pulse forming circuit 30.

The _first video signal (main video signal) _{S Both} video _{signals S} A composite video signal S _O having this mixing ratio is obtained at the terminal 23.

30 is an example of a forming circuit for forming this mix control pulse V _M , and in this example, it is applied to obtain a so-called horizontal wipe waveform as shown in FIG. 4C.

A reference voltage (DC voltage whose value can be varied) V _DC is supplied to the terminal 31, and this is supplied to the level shift circuit 32, which has a constant voltage interval ΔV as shown in FIG. 2A, for example. In this example there are four level-shifted reference voltages V _A to V _D
are formed, and these reference voltages V _A to V _D are supplied to the slice circuit 33.

The slice circuit 33 has four differential amplifiers 33A to 33D as shown in the figure, and the corresponding differential amplifier 3
The above reference voltages V _A to V _D are applied to the - terminals of 3A to 33D.
is supplied to the + terminal from the terminal 34,
A wipe signal V _S having a sawtooth waveform with a horizontal period as shown in FIG. 2B is commonly supplied.

Here, the relationship between the wipe signal V _S and the reference voltages V _A to V _D is set in advance so that the minimum reference voltage V _A is a predetermined level higher than the peak value of the wipe signal V _S. If this wipe signal V _S that changes in a horizontal period is supplied to the differential amplifiers 33A to 33D, different levels of the wipe signal V _S will be sliced depending on the values of the reference voltages V _A to V _D , respectively. , the time point at which the slice output is obtained differs depending on the reference voltages V _A to V _D.

The slice outputs (voltages) output from these differential amplifiers 33A to 33D are supplied to a resistance attenuator 35. Each resistance attenuator 35 is composed of a pair of resistors 35A and 35B connected in series,
The respective resistance values are selected to be different predetermined values. The level-controlled pulse voltages V _MA to V _MD of predetermined values obtained from the connection midpoint of the resistors 35A and 35B are supplied to the voltage synthesis circuit 36.

The voltage combining circuits 36 each include transistors Q _A to Q _D.
The pulse voltages V _MA to V _MD are supplied to the bases of the corresponding transistors Q _A to Q _D , respectively, and the emitters of these transistors Q _A to Q _D are commonly connected to the resistor R _O. The voltage obtained across this resistor R _O , that is, the composite voltage V _M is used as the mix control pulse V _M .

Here, in this example, it is assumed that the pulse voltages V _MA to V _MD are all equal to ΔE.

Now, in this invention, the mixing ratio and wipe position of the wipe video signal S _Y with respect to _the main video signal _S Resono Mix Control Pulse
It is variably controlled by the position of V _M.

That is, in this example, as shown in FIG. 3, when the voltage of mix control pulse V _M is 0, the level of wipe video signal S _Y is 0,
In other words, it is not wiped at all, whereas the mix control pulse V _M level is V _MA
(equal to ΔE, which is obtained when V _A < V _M ), the level of _the main video signal _S
The wiped video signal S _Y is mixed at a mixing ratio such that the level of the wiped video signal S Y is 25%, and a composite video signal S _O is formed.

The peak value of mix control pulse V _M is
2ΔE, that is, V _MA + V _MB (when V _B < V _M ), _the main video signal _S Similarly, the level of the mix control pulse V _M is 3ΔE, that is, V _MA + V _MB +
When V _MC (when V _C < _VM ), the level of _the main video signal _S The mixture is mixed at a good mix ratio, and the mix control pulse V _M level is 4ΔE,
That is, when V _MA +V _MB +V _MC +V _MD (when V _D < V _M ) or more, only the horizontal section Td where a voltage of 4ΔE is obtained,
The video mixing circuit 20 is configured to output only the wipe video signal S _Y.

Therefore, if the reference voltage V _DC is gradually lowered,
The mixed images obtained at this time are shown in FIGS. 4 to 7.

First, in the state of V _A > V _S , the differential amplifier 33A ~
Since all 33D outputs are low level,
Pulse voltages V _MA to V _MD are all zero, and transistors Q _A to Q _D are all off.

As a result, the level of mix control pulse V _M obtained at terminal 37 is zero. As a result, the composite video signal S _O obtained at terminal 23 is the main video signal
Available in S _X only.

On the other hand, if the reference voltage V _DC is varied, that is, the voltage V _DC is lowered so that the level becomes low, a state as shown in FIG. , a predetermined pulse voltage V _MA is output, and accordingly, the transistor Q _A is turned on, and a mix control pulse as shown in FIG. 4B is output to the terminal 37.
V _M is output. Therefore, during the period Ta during which the mix control pulse V _M is obtained, the main video signal S _X is output with a mixing ratio of 75% and the wipe video signal S _Y is 25%.

As a result, as shown in FIG. 4C, the image _X corresponding to the main video signal S During the period , the wipe image Y is superimposed on the main image X at a mixing ratio as shown.

If the reference voltage V _DC is fixed at that position, a wipe waveform as shown in Fig. 4C will be obtained, but from this state, the reference voltage V _DC can be further controlled towards a lower level, for example, as shown in Fig. 5A. If the reference voltage V _DC is controlled in such a state, the second
Since a predetermined slice output is also obtained from the differential amplifier 33B, the pulse voltage V _MB becomes positive, and as a result, the transistor Q _B is also turned on and a DC output in which the pulse voltage V _MB is superimposed on the pulse voltage V _MA for the period Tb is generated.
2ΔE is obtained as mix control pulse V _M.

As a result, the period Ta during which the pulse voltage V _MA is obtained is
Whereas main image X and wipe image Y are mixed at the same mixing ratio as explained in Fig. 4,
In period Tb, 50% as shown in Figure 3.
The main image X and the wipe image Y are superimposed on each other at a ratio of .

Here, the slice position of the reference voltage V _A with respect to the wipe signal V _S shifts from the right to the left as the reference voltage V _A decreases, so the period Ta also becomes wider than in the case of FIG. 4. Figure 4C
Even with the mixture ratio shown in , the overlapping area gradually expands and its position shifts from the right side to the left side.

However, even with the mixing ratio shown in FIG. 4C, the area synthesized is a horizontal period of 0≦Ta≦W/4.

If the reference voltage V _DC is further lowered and a slice level relationship is achieved as shown in FIG. 6A, for example,
Since a predetermined slice output is obtained from each of the first to fourth differential amplifiers 33A to 33D, pulse voltages V _MA to V _MD are formed correspondingly, and each transistor Q _A to Q _D is Turn on at different times,
As a result, a mix control pulse V _M as shown in FIG. 6B is obtained at the terminal 37. Here, the periods Ta to Tc are all W/4, and the period
Td is the period of slice level V _D.

By using such a mix control pulse V _M , wipe patterns having different mix amounts as shown in FIG. 6C can be obtained.

If the reference voltage V _DC is further lowered, a slice state as shown in FIG. 7A will occur;
Mix control pulses as shown in Figure B
As a result of the formation of V _M , correspondingly, wipe patterns having different mixing ratios are obtained shifted from the right side to the left side, as shown in FIG.

To summarize the above, by continuously varying the reference voltage V _DC , the state shown in Fig. 4C changes to the state shown in Fig. 7 C, and by further lowering the reference voltage V _DC , the wipe video signal Only image Y based on S _Y will be displayed.

Such image transitions are very effective video processing when the current scene is unfolded while remembering the past scene.

As described above, according to this embodiment, the composite images superimposed with different mixing ratios are sequentially scrolled from the right side to the left side in a band-like manner so that the mixing ratios are successively different, so that images such as flashback scenes, etc. Suitable for use in scenes.

In addition, by changing the mixture ratio in the horizontal wipe state described above, the wipe position and mixture amount were changed and scrolled sequentially to the left, but if the polarity of the wipe signal V _S is reversed, the same result as described above can be achieved. Even with a mixture ratio and a strip pattern, it is possible to scroll from left to right, and if both the vertical and horizontal wipe signals V _S are supplied to terminal 34 as shown in FIG. 8, as shown in FIG. The image Y accompanying the wipe video signal S _Y can be scrolled diagonally from the upper right to the lower left with a wipe pattern. Therefore, the wipe signal applied to terminal 34
By setting V _S to various values, it becomes possible to wipe composite images with different mixing ratios depending on the desired wipe pattern.

In addition, in the above, the reference voltage V _DC is applied to the terminal 31.
and a wipe signal V _S to terminal 34;
By varying the reference voltage V _DC with respect to a common wipe signal V _S , composite images as shown in Figures 4 to 7 _were formed. The wipe signal V _S supplied to the terminal 34 is, for example, a wipe signal having four levels of peak levels as described above, and is supplied to the corresponding differential amplifiers 33A to 33D, as well as the commonly supplied reference voltage V. Even if the value of _DC is varied, a wipe waveform similar to that described above can be realized.

Effects of the Invention As explained above, in this invention, the mix control pulse forming circuit 20 is provided which can vary the mixing ratio of the wipe video signal to the main video signal and the wipe position, and the mix control pulse V _M can be changed. Therefore, we have made it possible to change multiple composite images with a predetermined mixing ratio over time with different wipe positions, so that the current scene and past scene can be changed over time like a flashback scene. Changes can be made in a flow-like manner, and special video effects with high video effects can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a connection diagram showing an example of a video special effect circuit according to the present invention, and FIGS. 2 to 9 are waveform diagrams for explaining its operation. 10 is a video special effect circuit, 20 is a video mixing circuit, 30 is a mix control pulse V _M forming circuit, V _DC is a reference voltage, V _S is a wipe signal, 32
is a level shift circuit, 33 is a slicer, 36 is a synthesis circuit, S _X is a first video signal, S _Y is a second video signal, and S _O is a composite video signal.

Claims (1)

[Claims] 1 A mixing circuit that mixes a first video signal with a second video signal to be wiped to obtain a composite video signal; It consists of a forming circuit that obtains a mix control pulse that can vary the mixing ratio and wipe position, and this forming circuit is supplied with a horizontal or vertical synchronized wipe signal and a variable reference voltage for varying the wipe position. Video special effects circuit.