Abstract: The red, green and blue video output of a camera, telecine channel or video tape recording is fed into a video effects unit including red, green and blue circuits, each of which are the same. Each of these color circuits includes an emitter follower feeding into a paraphase amplifier which produces inverted and non-inverted signals which are fed into an emitter follower arrangement, across which is coupled a potentiometer having a tap feeding into an amplitude mixer. Also feeding into the amplitude mixer are signals derived from an audio circuit, signals derived from a blanking circuit and signals derived from a luminance circuit. These four signals or selected of these signals are amplitude mixed and fed into a further emitter follower arrangement and thence to a buffer amplifier, whereat a clamping circuit exerts a clamping action based on clamping pulses generated from a synchronization or composite video signal.