FIELD: information technology.
SUBSTANCE: invention relates to image decoding and encoding. Image decoding method includes steps of obtaining, when a block adjacent on left side with current block, and a block adjacent from above with current block, can be used as reference blocks, a prediction quantization parameter based on average value of quantisation parameter for block adjacent on left side, and a quantisation parameter for block adjacent from above; obtaining, when a block adjacent on left side with current block, and a block adjacent from above with current block, cannot be used as reference blocks, a prediction quantization parameter based on quantisation parameter of a processing module, not adjacent to current block; obtaining from stream information difference information, indicating difference between obtained prediction quantisation parameter and quantisation parameter of current block; and generating a quantisation parameter for current block based on prediction quantisation parameter and difference information.
EFFECT: high efficiency of encoding quantisation parameters.
20 cl, 33 dwg
