IMAGE ENCODER, ENCODED IMAGE RECORDING MEDIUM, IMAGE DECODER, IMAGE ENCODING METHOD AND ENCODED IMAGE TRANSMITTING METHOD

摘要

PROBLEM TO BE SOLVED: To improve rate control accuracy and the picture quality of the encoded result while well reflecting it with the local character of source image by calculating a local characteristic value from a complexity index value found from a converting input and correcting quantization width while using this value and control information. SOLUTION: A parameter calculating means 9 finds the complexity index value of inputted converting input image, calculates a quantization width correction parameter, valid image discriminated result and valid image area rate from this value, outputs these values to a quantization width determining means 10, determines the quantization width through the quantization width determining means 10 based on these calculated values, target data amount and target bit as the target value of output quantity of the encoded result found by a control information setting means 51 and outputs it to a quantizing means 3. Then, by correcting the quantization width to be used for the quantizing means 3, the rate control is performed concerning the amount of encoded data to be generated.