Method and apparatus for image encoding and image decoding

An image encoding method comprising:

• performing prediction processing by using a reference image signal in accordance with a selected prediction mode in units of block obtained by dividing an image frame in order to generate a predicted image signal in units of prediction block;
• performing transform and quantization with respect to a prediction error signal indicative of a difference value between the predicted image signal and an input image signal in order to generate a quantized transform coefficient;
• performing entropy encoding with respect to the quantized transform coefficient in order to generate encoded data;
• performing inverse quantization and inverse transform with respect to the quantized transform coefficient in order to generate a decoded prediction error signal;
• adding the predicted image signal to the decoded prediction error signal in order to generate a locally decoded image signal;
• deriving prediction complexity indicative of a degree of complication of the prediction processing;
• determining filtering strength for the locally decoded image signal to become low as the prediction complexity increases;
• performing deblocking filter processing with respect to the locally decoded image signal in accordance with the filtering strength;
• and
• storing the locally decoded image signal after deblocking filter processing to be used as the reference image signal.