Unified forward+inverse transform architecture for HEVC

The upcoming HEVC video coding standard supports many transform sizes ranging from 4-point to 32-point in square and rectangular form. Multiple transform sizes improve coding efficiency, but also increase the implementation complexity. Furthermore both forward and inverse transforms need to be supported in various consumer devices. This paper presents a unified forward+inverse transform architecture for HEVC. The unified architecture makes use of symmetry properties that exist in the HEVC forward and inverse transform matrices to achieve hardware sharing across different transform sizes and also between forward and inverse transforms. It uses 43-45% less area than separate forward and inverse core transform implementations.