Video signal coding method and device adapted to control code amounts according to the characteristics of pictures

A picture signal coding device comprising:

• an importance calculation portion for detecting a visual importance for each macro block based on the absolute value level of an inputted picture and orthogonal transformation data in the case of intraframe encoding and based on the absolute value level of inputted pictures, orthogonal transformation data, differential picture and motion vector in the case of interframe encoding;
• and
• an activity function generation portion for calculating an activity for each macro block in each frame of the inputted pictures based on the differential picture and visual importance and, generating an activity function indicating an accumulation of the activity for each macro block in a coding frame, and calculating a frame activity of the coding frame;
• a target code amount determination portion for determining a target code amount of the coding frame by using at least one of a remaining code amount at the time of coding the coding frame, a generated code amount of previously encoded frames, an activity of the previously encoded frames, an occupancy of a buffer, and the activity of the coding frame;
• a reference scaling factor calculation portion for calculating a reference scaling factor of the coding frame by using at least one of a scaling factor of the previously encoded frames, the generated code amount of the previously encoded frames, the frame activity of the previously encoded frames, the frame activity of the coding frame, and the target code amount;
• a coding portion for generating a prediction model based on the activity function and the target code amount, coding the coding frame macro block by macro block by using the prediction model, the reference scaling factor, and the importance, and generating encoded data.