Low Power Motion Estimation and Motion Compensation Block IPs in MPEG-4 Video Codec Hardware for Portable Applications

Chi-Weon YOON  Hoi-Jun YOO  

IEICE TRANSACTIONS on Electronics   Vol.E86-C   No.4   pp.553-560
Publication Date: 2003/04/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on High-Performance, Low-Power System LSIs and Related Technologies)
Category: Architecture and Algorithms
low power,  motion estimation,  motion compensation,  MPEG-4,  

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In this paper, two low power hardware structures essential for MPEG-4 video codec are proposed for portable applications. First, an adaptive bit resolution control (ABRC) scheme is proposed for a processing element (PE) in a systolic-array type motion estimator (ME). By appropriately modifying the datapath of PE to exploit the correlations in pixel values, its structure is optimized in terms of both hardware cost and low power consumption. As a result, power is saved up to 29% compared with a conventional PE while the computation accuracy is preserved and the overhead is kept negligible. Second, a low power motion compensation (MC) accelerator is proposed. By embedding DRAM whose structure is optimized for low power consumption, the power consumption for external data I/Os is dramatically reduced. In addition, distributed nine-tiled block mapping (DNTBM) with partial activation scheme in the frame buffer reduces the power for accessing frame buffer up to 31% compared to a conventional 1-bank tiled mapping. With the proposed MC accelerator, MPEG-4 SP@L1 decoding system is fabricated using 0.18 µm embedded memory logic (EML) technology.