Patent ID: 8331449

Claim:
An intra prediction method of compressing and encoding an image by a computer processor, the method comprising the steps of: comparing an SAD value C calculated from macro block data of a present frame and a previous frame with a reference value K and determining a prediction method; and selectively performing on input macro block data a first method of determining a best mode and a block size by prediction in a plurality of prediction modes based on spatial directivity and generating prediction data and a second method of generating prediction data using the best mode and the block size used in the previous frame, depending on the determined prediction method; wherein the step of determining the prediction method includes: calculating an average value SAD_avg of the SAD values calculated from the previous frame and a pre-previous frame; and comparing the average value with a threshold value K — 1 adaptively determined in advance and adjusting the reference value K in accordance with the comparison result; and wherein the step of adjusting the reference value includes: raising the reference value by determining that the image has a small variation between the previous frame and the present frame when the average value is equal to or less than the threshold value; and lowering the reference value by determining that the image has a great variation between the previous frame and the present frame when the average value is greater than the threshold value.