Image processing apparatus and method

An image processing apparatus for decoding a bit stream, the image processing apparatus comprising:

• a decoding unit that decodes a bit stream including a difference quantization parameter which is a difference between a current quantization parameter which is set for a current coding unit and a predicted quantization parameter, with a size-variable coding unit as a unit of processing, and generates quantization data, the size-variable coding unit is obtained by recursively dividing a maximum coding unit of fixed size in a unit of sequence according to a quadtree structure;
• a predicted quantization parameter setting unit that sets a quantization parameter which is set for a surrounding coding unit located nearby which is not adjacent to the current coding unit as a predicted quantization parameter, when it is determined, based on a location of the current coding unit in a maximum current coding unit, that all adjacent coding units adjacent to the current coding unit are located outside the current maximum coding unit, and are not in an available state;
• a quantization parameter setting unit which sets the current quantization parameter by adding the difference quantization parameter to the predicted quantization parameter set by the predicted quantization parameter setting unit;
• and
• an inverse quantization unit that inversely quantizes quantized data generated by the decoding unit using the current quantization parameter set by the quantization parameter setting unit.