Abstract: In a composite video system having a digitized composite video signal to be modified, wherein the digitized video signal has discrete values having sampling frequency Nf.sub.s where N is an integer greater than one, and f.sub.s is the color subcarrier frequency of the video input signal, a method and apparatus for utilizing look-up tables to create special color effects without decoding to luminance and chrominance, the method having the steps of storing in memory N sets of predetermined values such that the sets are addressable in a desired predetermined order and such that the predetermined values relate to a discrete equal distant points on a color subcarrier frequency wave corresponding to a desired color, retrieving from memory the stored values at a rate Nf.sub.s such that the N sets are addressed in the predetermined order, and using the digitized composite video signal to address said memory, to produce a digitized video output signal with different values, as desired.

Abstract: In a composite video system having a digitized composite video signal to be modified, wherein the digitized video signal has discrete values having sampling frequency Nf.sub.s where N is an integer greater than one, and f.sub.s is the color subcarrier frequency of the video input signal, a method and apparatus for utilizing look-up tables to create special color effects without decoding to luminance and chrominance, the method having the steps of storing in memory N sets of predetermined values such that the sets are addressable in a desired predetermined order and such that the predetermined values relate to a discrete equal distant points on a color subcarrier frequency wave corresponding to a desired color, retrieving from memory the stored values at a rate Nf.sub.s such that the N sets are addressed in the predetermined order, and using the digitized composite video signal to address said memory, to produce a digitized video output signal with different values, as desired.

Abstract: In a linear video mixer, two video signals are combined into a single output signal in response to any n bit byte digital control signal, the mixer having a buffered isolation input, a series of n electrically controlled double-throw type switches, each of whose control input is connected to a corresponding bit of the desired digital control signal; the two inputs of each switch are connected to one of the two respective buffered video signals to be mixed, and the output of each switch is connected to respective rungs of a 2R/R resistor ladder network that itself is connected to a buffer having relatively high output impedance; the most significant bit down to the least significant bit of the digital control word is connected to the switches in the switch-ladder network to achieve the desired output, which in combination with the resistor ladder network, will achieve the desired combination of input video signals.

Abstract: In a digital composite video processing system where the video signal has a color subcarrier F.sub.sc, horizontal and vertical sync signals and produces multiple color fields, and where the system has system clock of frequency nF.sub.sc for digitizing and a horizontal counter counting to L incremented by the system clock, a method and apparatus is disclosed for synchronizing the system clock to color burst and synchronizing the horizontal counter to horizontal sync, whereby a window of width W clock counts wide is selected such that HSYNC is desired to occur at clock pulse P+W/2 when P is an integer; a determination is made whether HSYNC occurs before, within or after the window, the system counter is reset at counts L-(n/2), L, or L=(n/2) determined by where HSYNC appeared in relation to the window, and color reference signal is sampled to determine which of the four color fields is being processed, all in order to properly process the color video signals.