Patent ID: 8238421

Claim:
An apparatus for estimating an H.264 compression mode, the apparatus comprising: a macroblock mode estimator which comprises mode history tables and a table management unit managing these tables, in order to estimate a mode of a current macroblock from input macroblock coordinates, wherein the macroblock mode estimator comprises: the mode history tables, each comprising a mode history indexing field and a mode estimation sequence field corresponding to each indexing field; and the table management unit comprising a mode estimator estimating a mode using the mode history tables and an estimated mode updater updating a mode stored in a table to the estimated mode; a macroblock image characteristic calculator calculating a macroblock image characteristic from macroblock image information, wherein the macroblock image characteristic calculator comprises: a macroblock evenness calculator obtaining variance of pixel values in a macroblock in order to calculate the evenness of the macroblock from input macroblock image information; and an evenness classifier determining a number of a mode history table by dividing the calculated macroblock evenness by n and outputting this 1/n-classified evenness as a mode history table selection signal, wherein n is an integer equal to or greater than 1.