Abstract: A digital input signal having a sampling frequency f is interpolated by a factor N, where N is a positive integer, whereby a first digital signal having a sampling frequency Nf is generated. A non-linear operation is carried out on the first digital signal having the sampling frequency Nf and a second digital signal having the sampling frequency Nf is provided. The second digital signal is decimated by the factor N and thereby provides a digital output signal having the sampling frequency f.

Abstract: An improved luminance video self keyer extracts a key signal from an unshaped input video signal as a function of a low and a high clip level. The input video signal is subsequently "shaped" as a function of the key signal and the low clip level. The result is a shaped video signal and an associated key signal that are combined with a secondary video signal without resorting to double multiplication of the input video signal by its associated key signal to produce a desired combination of the two video signals.

Abstract: A mix effects based switcher architecture provides for processing of video signals with associated key signals throughout, the mix effects (M/E) banks within the switcher outputting both a composited video signal and a composited key signal for use by subsequent M/E banks. The outputs of the M/E banks may be combined together before being input to an output M/E bank. The output M/E bank provides a layered video signal with associated composited key signal at the output of the switcher.

Abstract: Video signal processing apparatus comprises at least first and second source selectors each having a plurality of input terminals, for receiving a plurality of video signals respectively, and at least two output terminals. A set of video processors each have an input terminal and an output terminal. A processor selector is provided for connecting each source selector output terminal selectively to each video processor input terminal. First and second output devices each have a plurality of input terminals connected to the output terminals of the video processors respectively and also have an output terminal. Operator interfaces are connected to the processor selector for defining a first subset of video processors having their input terminals connected to the output terminals of the first source selector and a second subset of video processors having their input terminals connected to the output terminals of the second source selector.

Abstract: A video switcher comprises a source selector having a plurality of input terminals for connection to a plurality of video sources respectively, and at least two output terminals. At least two processing channels each have an input terminal connected to an output terminal of the source selector and also have an output terminal. A video combiner has video input terminals connected to the output terminals of the processing channels and is operative to combine the output signals provided by the processing channels in dependence upon priority signals.

Abstract: A multiple television standards input selector and convertor selects a video signal from among a plurality of television standard format input sources including encoded video, analog component video and digital video. The selected video signal is converted to a predetermined standard format video signal for further processing by a digital video effects device. The selection of the video signal occurs within a vertical interval period so that no visible effect is detectable on a display when switching between video sources.

Abstract: A chroma keying system which prevents the production of a chroma key signal when the primary color signals are equal is described. This system effectively prevents chroma keys on monochrome portions of color foreground camera signals. These monochrome portions are typically caused by uneven studio lighting and the resulting shadows and reflections. The system includes a comparator which compares the R, G, and B signals and generates an inhibit signal therefrom. This inhibit signal is then used to prohibit the generation of a chroma key signal.