Apparatus and method for decoding extended color space data

A method for decoding an input signal, comprising:

• receiving image data signals in a digitized gamma-corrected YCbCr format encoded in an extended YCC color space;
• normalizing the received image data signals to recover normalized luminance and chrominance Y′Cb′Cr′ formatted data signals from the YCbCr formatted data signals;
• scaling and offsetting the normalized Y′Cb′Cr′ formatted data signals to offset for guard-banding;
• performing a conversion operation on the normalized, scaled and offset Y′Cb′Cr′ formatted data signals to obtain extended R′G′B′ formatted data signals;
• scaling and offsetting the extended R′G′B′ formatted data signals, the scaling and offsetting for each extended R′G′B′ component determined by an amount of negative offsetting needed so the extended R′G′B′ components will be substantially non-negative for any potential input YCbCr format value and fall within a given positive range of integer values;
• and
• performing a degamma operation on the extended R′G′B′ formatted data to obtain RGB formatted data without gamma correction;
• wherein the scaling and offsetting of the normalized Y′Cb′Cr′ formatted data signals is determined by:
• Y=s11×Y′+s12
• Cb=s21×Cb′+s22
• Cr=s31×CR′+s32
• where s11, s21, and s31 are scaling factors, and s12, s22, and s32 are offset constants.

A method for decoding an input signal, comprising:

• receiving image data signals in a digitized gamma-corrected YCbCr format encoded in an extended YCC color space;
• normalizing the received image data signals to recover normalized luminance and chrominance Y′Cb ′Cr′ formatted data signals from the YCbCr formatted data signals;
• scaling and offsetting the normalized Y′Cb′Cr′ formatted data signals to offset for guard-banding;
• performing a conversion operation on the normalized, scaled and offset Y′Cb′Cr′ formatted data signals to obtain extended R′G′B′ formatted data signals;
• scaling and offsetting the extended R′G′B′ formatted data signals, the scaling and offsetting for each extended R′G′B′ component determined by an amount of negative offsetting needed so the extended R′G′B′ components will be substantially non-negative for any potential input YCbCr format value and fall within a given positive range of integer values;
• and
• performing a degamma operation on the extended R′G′B′ formatted data to obtain RGB formatted data without gamma correction;
• wherein performing the normalized, scaled and offset Y′Cb'Cr' formatted data signals are converted by a matrix multiplication represented by:
• R′=d11×Y+d12×Cb+d13×Cr
• G′=d21×Y+d22×Cb+d23×Cr
• B′=d31×Y+d32×Cb+d33×Cr
• where the matrix coefficients dij represent the contribution of the respective YCbCr component to the respective R′G′B′ component.