Entropy encoder, video coding apparatus, video coding method and video coding program

摘要

An entropy encoder, a video coding apparatus, a video coding method and a video coding program can cope with the adverse effects that arise as a result of a local increase of overhead code quantity. The quantization parameter output form the code quantity control unit of a video coding apparatus is input to a third arithmetic unit before being input to the context initializer in an entropy encoder and a quantization parameter offset value is subtracted from it there. The discrepancy relating the generation probability of a symbol where significant coefficients exist can be improved by initializing an arithmetic coding context by using the quantization parameter obtained by subtracting a predetermined value form the quantization parameter defined by a rate control unit.