A configurable H.265-compatible motion estimation accelerator architecture for realtime 4K video encoding in 65 nm CMOS

Abstract

The design for a configurable motion estimation accelerator is presented and demonstrated as suitable for realtime digital 4K as well as H.265/HEVC. The design has two 4-KB frame memories necessary to hold the active and reference frames, designed using a standard cell memory technique, with line-based pixel write, and block-based pixel accesses. It computes a 16 pixel sum of absolute differences (SAD)s per cycle, in a 4 × 4 block, and is pipelined to take advantage of the high throughput block pixel memories. The architecture supports configurable search patterns and threshold-based early termination which allow for run-time tradeoffs to be made between pixel throughput and final quality of result. CMEACC is independently clocked and can operate up to 812 MHz at 1.3 V in 65 nm CMOS, achieving a throughput of 105 MPixel/sec for a single instance while consuming 0.933 pJ × sec/Pixel, and occupying approximately 1.04 mm2 post place-and-route in 65 nm CMOS. While operating at 0.9 V, the presented design consumes 0.393 nJ/Pixel, which scales to 8.06 mW at 22.26 FPS in 720p.