Patent ID: 8675726
Filing Date: 2014-03-18
Classification: H04N

Abstract:
1. A method of encoding a video, the video including a block of pixel data, the pixel data for the block having been transformed to a set of transform domain coefficients, the method comprising: quantizing the set of transform domain coefficients using a quantization step size to obtain a set of hard quantized coefficients, wherein each hard quantized coefficient is an integer-value hard-quantization level to which the coefficient has been quantized; for each of the transform domain coefficients in the set of transform domain coefficients, without changing the quantization step size or other quantization parameters, performing soft decision quantization to obtain a soft quantized coefficient using a rate-distortion calculation over a search range of quantization levels for that transform domain coefficient, wherein the search range of quantization levels for that transform domain coefficient is a range of integers around the integer-value hard-quantization level and wherein that range is constrained within a number of quantization levels of the hard quantized coefficient, and wherein the number of quantization levels is based on a threshold value less accumulated differences between previous soft quantized coefficients for the set of transform domain coefficients and corresponding hard quantized coefficients; and entropy encoding the soft quantized coefficients to generate encoded video data.