Abstract: A chroma keyer color discriminator wherein orthogonal color difference signals B-Y and R-Y are rotated through an angle .phi. corresponding to a desired chroma keying signal where R and B are red and blue signals and Y is the luminance signal where Y=0.3R+0.59G+0.11B. The rotated signals (R-Y)' and (B-Y)' are processed to develop B'-G' and B'-R' signals to enhance the selectivity of the discriminator. Difference signals other than B-Y, R-Y, B'-G', and B'-R' may also be employed.

Abstract: This invention relates to a mix/effects switch arrangement and a mix/effects switching system including the switch arrangement. The mix/effects switch arrangement includes five switches each of which has two input terminals, an output terminal and a control terminal. One of the switches is the output switch, and a first and second one of the remaining switches are serially arranged to constitute an input to one of the input terminals of the output switch. The remaining two switches are serially arranged in parallel to constitute the input to the other input terminal of the output switch. At least the output switch constitutes a soft switch, and, preferably, the two input switches also are soft switches. In the switching system, a source of first background video signal is applied to one input terminal of an input switch, and a source of second background video signal is applied to one input of the other input switch.