Patent ID: 7970055

Claim:
An image data compression apparatus for performing compression processing of image data, comprising: a bit rate value detection unit for detecting an effective bit rate based on an image data volume after compression processing; a quantization step size value changing unit for inputting a a-target bit rate and a maximum value and a minimum value of a quantization step value used in the compression processing, wherein the quantization step value is increased by one step size between the maximum value and the minimum value is then output if the detected effective bit rate is higher than a first predetermined ratio of the target bit rate, and wherein the quantization step value is decreased by one step size between the maximum value and the minimum value and is then output if the detected effective bit rate is lower than a second predetermined ratio of the target bit rate; a frame rate control unit for inputting the maximum value and the minimum value of the quantization step value, wherein a number of skip frame is set to be increased by one number if the output quantization step value is equal to the maximum value, and wherein the number of skip frame is set to be decreased by one number if the quantization step value is set to be decreased down to a value which is the minimum value multiplied by a predetermined coefficient which is equal to one or more; and a frame skip unit for performing a frame skip process which discards frames corresponding to the set number of skip frame after passing one frame of the image data in before or after the compression process, wherein the frame skip process is executed if the quantization step value is higher than the maximum value.