Image processing apparatus and method

An image processing apparatus comprising:

• a quantization selection section for selecting a quantizer step for each quantization unit from among a plurality of quantizer steps;
• a temporary coding section for quantizing image data with the quantizer step selected by the quantization selection section to generate temporary quantized data, and calculating a quantization unit generated code amount, the quantization unit generated code amount being a generated code amount of each quantization unit of the temporary quantized data;
• a storing section for storing relationship information on a plurality of pieces of quantized data for prediction having different quantization unit generated code amounts at the quantizer step selected by the quantization selection section, the relationship information indicating a relationship between the plurality of quantizer steps and the quantization unit generated code amounts;
• a data selection section for selecting quantized data for prediction from the relationship information based on the quantization unit generated code amount of the temporary quantized data and the quantizer step selected by the quantization selection section;
• and
• a code amount prediction section for predicting the quantization unit generated code amounts for situations where the image data is quantized with quantizer steps not selected by the quantization selection section out of the plurality of quantizer steps, based on the quantized data for prediction selected by the data selection section.