Bandwidth Optimized and High Performance Interpolation Architecture in Motion Compensation for H.264/AVC HDTV Decoder

摘要

In this paper, we present high performance motion compensation architecture for H.264/AVC HDTV decoder. The bottleneck of efficient motion compensation implementation primarily rests on the high memory bandwidth demand and six-tap fractional interpolation complexity. To solve the bottleneck for H.264/AVC HD applications, three combined bandwidth optimization strategies are proposed to minimize the memory bandwidth for MB-based decoding process. To improve the interpolation hardware utilization and reduce the interpolation cycles, an interpolation classification scheme is proposed. By classifying the fifteen fractional pixels into five types and processing correspondingly, the interpolation cycles decrease significantly. A direct mapping memory cache characterized with circular addressing, byte-aligned addressing and horizontal and vertical parallel access is designed to support the proposed scheme. The hardware of proposed motion compensation is implemented at 100 M with 31.841 K logic gates, averagely 70-80% reduced memory bandwidth can be offered and the interpolation hardware can be fully utilized and interpolate one MB within 304 cycles, which can satisfy the real time constraint for H.264/AVC HD (1,920 x 1,088) 30 fps decoder. The design is implemented under UMC 0.18 μm technology, and the synthesis results and comparisons are shown.