Color modification on a digital nonlinear editing system

Abstract

A color modification system and method for reducing the number of computations performed on a pixel color. This reduction in computations increases the rate at which color modification may be performed and decreases the effects of rounding errors. Decreasing the effects of rounding errors produces a more accurate color modification, thereby reducing the likelihood of artifacts. The system and method performs color modification on a pixel color, where the color includes a first, second, and third component and each component defines a value of the color. The system includes a chroma lookup table having a plurality of entries. Each entry corresponds to a luma value and contains chroma coefficients. The chroma coefficients define color modifications to be applied to the components of the color. If a luma value is received, the chroma lookup table generates output chroma coefficients at an output. The output coefficients are generated by accessing the entry corresponding to the luma value, and extracting the output coefficients from the entry. The coefficients may include at least four matrix coefficients. The system may include a first matrix multiplier that receives the four matrix coefficients and at least a first and second of the color at an input and generate at least a first modified component and second modified component as output. The first matrix multiplier applies matrix multiplication to the first and second components using the four output chroma coefficients as the coefficients of the matrices. The chroma lookup table may defines a function of luma, and the function may be nonlinear.

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