Patent ID: 7778468
Filing Date: 2010-08-17
Classification: H04N

Abstract:
1. A decoding apparatus for decoding lossy, encoded transform code data, comprising: a histogram acquiring section that generates a frequency distribution of quantization index values from the encoded transform code data, the frequency distribution being based on a number of quantization indexes that become the quantization index values; a correction value estimating section that calculates a correction value r corresponding to each quantization index based on the frequency distribution of quantization index values generated by the histogram acquiring section; an expected-value calculating section that calculates an expected value of a probability density function of the quantization indexes based on the frequency distribution generated by the histogram acquiring section by using a linear function approximate to at least a portion of the frequency distribution generated by the histogram acquiring section; and a dequantization value outputting section that outputs corrected dequantization values corresponding to the quantization index values based on the frequency distribution of quantization index values generated by the histogram acquiring section and the correction value r for subsequent use in efficient decoding of the lossy, encoded transform code data, wherein the correction value estimating section corrects the dequantization values based on the expected value calculated by the expected-value calculating section, and when the expected-value calculating section determines a probability density function for a given quantization index value, the expected-value calculating section determines the linear function approximate to the frequency distribution using a value of where h(q) represents a frequency value of the given quantization index value, and h(q−1) and h(q+1) represent respective frequency values of adjacent quantization index values.