Low-power data-dependent 8×8 DCT/IDCT for video compression

Abstract

Traditional fast discrete cosine transform (DCT)/inverse DCT (IDCT) algorithms have focused on reducing arithmetic complexity and have fixed run-time complexities regardless of the input. Recently, data-dependent signal processing has been applied to the DCT/IDCT. These algorithms have variable run-time complexities. A two-dimensional 8 x 8 low-power DCT/IDCT design is implemented using VHDL by applying the data-dependent signal processing concept onto the traditional fixed-complexity fast DCT/IDCT algorithm. To reduce power, the design is based on Loeffler's fast algorithm, which uses a low number of multiplications. On top of that, zero bypassing, data segmentation, input truncation and hardwired canonical sign-digit (CSD) multipliers are used to reduce the run-time computation, hence reducing the switching activities and the power. When synthesised using CMC 0.18-μm 1.6V CMOSP technology, the proposed FDCT/IDCT design consumes 8.94/9.54 mW, respectively, with a clock frequency of 40 MHz and a processing rate of 320 M sample/s. This design features lower dynamic power consumption per sample, i.e. it is more power-efficient than other previously reported high-performance FDCT/IDCT designs.