This paper presents an efficient software cache implementation for H.264 motion compensation on scratchpad memory based systems. For a wide range of applications - especially multimedia applications, the data set is predictable, making it possible to transfer the necessary data before the computation. Some kernels, however, depend on data that are known just before they are needed, such as the H.264 motion compensation (MC). MC has to stall while the data is transfered from the main memory. To overcome this problem and increase the performance, we analyze the data locality for the MC. Based on this analysis, we propose a 2D Software Cache (2DSC) implementation. The 2DSC exploits the application characteristics to reduce overheads, providing in average 65% improvement over the hand programmed DMAs.