High-Level Synthesis Implementation of Transform-Exempted SATD Architectures for Low-Power Video Coding

This paper presents the first known high-level synthesis (HLS) implementation for the Sum of Absolute Transformed Differences (SATD) calculation. The proposed hardware architecture is designed for two SATD algorithms: a widespread Fast Walsh-Hadamard Transform (FWHT-SATD) and a recently introduced Transform Exempted scheme (TE-SATD). This 2-stage architecture is made up of two 1-D Walsh-Hadamard Transform (WHT) stages and a transpose buffer (TB) between them. The chosen HLS approach cuts down design time over contemporary design methods and thereby made it feasible to implement a set of dedicated FWHT-SATD and TE-SATD architectures for 4x4, 8x8, and 16x16 pixel blocks. All these six architectures were synthesized for 28 nm and 45 nm standard cell technologies, and their area and energy consumptions were analysed. TE-based implementations provide 6.0-8.3% total cell area savings and 6.9-12.7% better energy-efficiency than traditional FWHT approaches. Our proposal is the first to introduce TE-SATD architectures for up to 16x16 blocks and each of these tailored architectures was shown to provide better trade-off between silicon area and performance than their reference implementations.