A SRAM-saving two-stage storage strategy for the coefficients memories in HEVC encoders

In the High Efficiency Video Coding (HEVC) standard, the Largest Coding Unit (LCU) is already expanded to 64×64 blocks, which makes the memory cost much higher when compared with H.264 standard. To be more specific, the storage space needed for the coefficients in one LCU is as large as 8 KB. Worse still, a new notation of Transform Unit (TU) is introduced in HEVC to better improve the coding performance, which has 4 different candidate sizes and needs to be traversed to find the best TU partition. Thus, a large number of extra memory would be needed to store the temporary data during the searching process, which makes the total memory cost unbearable. In order to solve such a problem, this paper proposed a two-stage storage strategy for these memory, which fully utilized the feature of transform coefficients. When compared with normal methods, this design shows an obvious advantage both in the area cost and in the power assumption.