Patent ID: 8218621

Claim:
A data-mapping method for use in a motion compensation system, comprising: partitioning a frame stored in an external memory into a plurality of macroblocks; providing a plurality of access units each comprising at least one macroblock; fetching a plurality of frames from the external memory by loading the plurality of access units in a predetermined sequence; and providing a first cache index corresponding to a first memory group of a circular cache for a current data by selecting a plurality of bits in a first physical address of the external memory which is associated with the current data according to a frame width, wherein the current data is for decoding a first macroblock in the first access unit among the plurality of access units; providing a second cache index corresponding to a second memory group of the circular cache for a reference data by selecting a plurality of bits in a second physical address of the external memory which is associated with the reference data according to the frame width, wherein the reference data is for decoding a second macroblock loaded from a second access unit among the plurality of access units; mapping the current data to the first memory group according to the first cache index and mapping the reference to the second memory group according to the second cache index.