Highly Parallel and Fully Reused H.264/AVC High Profile Intra Predictor Generation Engine for Super Hi-Vision 4k*4k@60fps

Abstract

One high profile intra predictor generation engine is proposed in this paper. Firstly, hardware level algorithm optimization for intra 8 × 8 (I8MB) mode is introduced. The original candidate pixels for generating prediction samples of I8MB are replaced with boundary pixels of intra 4 × 4 (I4MB) blocks. Based on this adoption, full data reuse between predictors of I4MB and filtered samples of I8MB can be achieved with almost no quality loss. Secondly, one lossless two-4 × 4-block based parallel predictor generation flow is proposed. The original predictor generation flow is optimized from 16 stages to 10 stages for I4MB and Intra 16 × 16 (I16MB), which saves 37.5% processing cycles. For I8MB, similar methodology with different processing order of 4 × 4 scaled blocks is introduced. Thirdly, fully utilized hardwired engines for I4MB, I16MB and I8MB are proposed in this paper. Except DC (direct current) and plane modes, full data reuse among all intra modes of high profile can be achieved. Fourthly, for DC mode, one combined predictor generation process is introduced and predictor generation of I16MB's DC mode is merged into the process of I4MB's DC mode. Moreover, by configuring proposed hardwired engines, predictor generation of I16MB's plane mode and chrominance plane mode can be accomplished with only 50% cycles of original design. Totally, when compared with original full-mode design and latest dynamic mode reused design, the proposed predictor generation engine can achieve 89.5% and 73.2% saving of processing cycles, respectively. Synthesized by TSMC 0.18µm technology under worst work conditions (1.62V, 125°C), with 380MHz and 37.2k gates, the proposed design can handle real-time high profile intra predictor generation of Super Hi-Vision 4k × 4k@60fps. The maximum work frequency of our design under worst condition is 468MHz.