Patent ID: 7269219

Claim:
An encoder for encoding video signals, comprising: a processing circuit to generate blocks of video data from a video information signal; a transform circuit to generate DC luminance coefficients, DC chrominance coefficients, and AC chrominance coefficients for each of said blocks; a quantizer circuit to: receive a quantization parameter for at least one of said blocks; scale a luminance coefficient by a luminance scaling function Q luminance (p), that is at least three-segment piece-wise linear function, where p is a coefficient value; scale a chrominance coefficient by a chrominance scaling function Q luminance (p), that is at least three-segment piece-wise linear function; and quantize said luminance coefficient according to said luminance scaling function and quantize said chrominance coefficient according said chrominance scaling function; and a variable length coder to generate a variable length code based on the quantized luminance and chrominance coefficients.