3-tier dynamically adaptive power-aware motion estimator for h.264/AVC video encoding

The limitation of energy in portable communication/entertainment devices necessitates the reduction of video encoding complexity. The H.264/AVC video coding standard is one of the latest video codecs and features a complex Motion Estimation scheme that accounts for a major part of the encoder energy [2]. We therefore present a power-aware Motion Estimator for H.264 that adapts at run time according to the available energy level. We perform a set of adaptations at different Processing Stages of Motion Estimation. Our results show that in case of CIF videos (typically used in portable devices; but our approach is equally applicable to other video resolutions too), we achieve an average energy reduction of 52 times and 27 times as compared to UMHexagonS [12] and EPZS [14] respectively. This energy saving comes at the cost of an average loss of only 0.39 dB in Peak Signal to Noise Ratio (PSNR: an objective quality measure) and 23% increase in area (synthesized for 90nm technology).