Patent ID: 8098736
Filing Date: 2012-01-17
Classification: H03M,H04N

Abstract:
1. A coding method comprising: an audio coding step of coding audio data; and an image coding step of arithmetic coding, on a block basis, coefficients of frequency components which are generated by frequency transformation performed on picture data of a block which has a predetermined size of pixels, wherein said image coding step includes: scanning two-dimensional coefficients of a block in a predetermined scanning order starting at a low frequency component toward a high frequency component to obtain one-dimensional coefficients; generating a sequence made up of combinations including a Run value and a Level value from the one-dimensional coefficients, wherein the Run value indicates the number of proceeding zero coefficients, the value of which is zero, and the Level value indicates a value of non-zero coefficient, the value of which is non-zero, and is subsequent to the zero coefficients; performing arithmetic coding on each absolute value of the Level value included in the combinations according to a predetermined order starting at a high frequency component toward a low frequency component, by using a plurality of probability tables; and switching a probability table to a new probability table based on a result of a comparison of an absolute value of a target Level value to be coded with a predetermined threshold value, wherein, in the switching, the switching between a plurality of probability tables is performed into one direction such that each probability table, which has been used before said new probability table, is not used after switching to said new probability table.