Patent ID: 6496228
Filing Date: 2002-12-17
Classification: G06F,G06K,G11B,H04N

Abstract:
A system for detecting significant scenes and selecting keyframes of source video, comprising:a receiver which receives source video as macroblocks including blocks of DCT coefficients and frames; a summer which calculates a sum for each type of block within a macroblock based on: SUM[I]=&Sgr;k,jABS(DCT1k,j[I]âˆ’DCT2k,j[I]) â€ƒwhere: k is the number of macroblocks in width of a frame, k=1 to Frame-width/16, j is the number of macroblocks in height of a frame, j=1 to Frame-height/16, I is the number of blocks in a macroblock, I=1 to number of blocks in macroblock, DCT1k,j and DCT2k,j are DCT coefficients for the specified macroblock for a previous and a current frame, respectively, and ABS is an absolute value function; a threshold adjustor which adjusts a first threshold and a second threshold based on the category of the source video, a first comparator for comparing each SUM[i] to the first and second thresholds and saving the current frame as a keyframe in a frame memory if SUM[i] is greater than the first threshold, incrementing a static scene counter if less than the second and saves the previous frame in a temporary memory, and resets the static scene counter otherwise; and a second comparator which compares the static scene counter to a predetermined number and transferring the most previous video frame saved in the temporary memory to the frame memory as a keyframe.