Patent ID: 6650785
Filing Date: 2003-11-18
Classification: H03M,H04N

Abstract:
An image coding method in which variable length coding process is performed to transform coefficients by referring to a variable length code table comprising a plurality of reference events, consisting of Last, Run Level, paired with reference variable length codes, wherein the variable length coding process comprises:obtaining an input event consisting of Last Run, Level corresponding to said transform coefficients, comparing said input event with a reference event in said table, and if said input event accords with maid reference event, outputting a variable length cede corresponding to said reference event, and if said input event does not accord with any reference events in said table, obtaining a second transformed input event, by transforming the Run value of said input event using a predetermined function, comparing said second transformed input event with a reference event in said table, and if said second transformed input event accords with said reference event, outputting a contra code and a third mode code followed by a variable length code corresponding to said reference event, and if said second transformed input event doe not accord with any reference events in said table, obtaining a first transformed input event, by transforming the Level value of said input event using a predetermined function, comparing said first transformed input event with a reference event in said table, and if said first transforms input event accords with said reference event, outputting a control code and a second mode code followed by a variable length code corresponding to said reference event, and if said first transformed input event does not accord with any reference events, outputting a control code an a first mode code followed by a fixed length code corresponding to said input event.