Patent ID: 8045614

Claim:
A method for digital encoding and decoding, comprising processing digital symbols representing a moving image, each symbol S having a bit depth N, to provide intermediate variables X, each having a bit depth N+K, where K is a function of the processing, quantizing each intermediate variable X with a quantizing step size QS N to produce a quantized data word Q, wherein QS N is a function of a quantization parameter QP, which function has been normalized to the most significant bit of the N-bit bit depth, processing, including entropy coding, the quantized data words Q to provide an encoded bitstream, processing, including entropy decoding, the encoded bitstream, to provide quantized data words Q, dequantizing each quantized data word Q with a dequantization step size QS M to produce a dequantized intermediate (M+K)-bit variable X′ that approximates the intermediate (N+K)-bit variable X, wherein QS M is the same function of the quantization parameter QP as is QS N but has been normalized to the most significant bit of an M-bit bit depth, and processing the intermediate variables X′ to produce digital symbols, each symbol S′ having a bit depth M, representing an approximation of said moving image.