IMAGE CODING METHOD, IMAGE DECODING METHOD, IMAGE CODING DEVICE, AND IMAGE DECODING DEVICE

摘要

Provided is an image coding method whereby it is possible to alleviate image quality degradation when inter-screen prediction is continuously employed. An image coding method which quantizes a plurality of pictures and codes the plurality of pictures comprises: a quantization width determination step (S101) which determines a first quantization width for a first picture of a plurality of pictures, which is defined in each prescribed interval in display order, and a second quantization width for a second picture which differs from the first picture; and a quantization step (S102) which quantizes the first picture at the first quantization width and quantizes the second picture at the second quantization width. In the quantization width determination step (S101), the first quantization width and the second quantization width are determined such that the first quantization width is smaller than the second quantization width.