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This paper describes a quarter video graphic array/common intermediate format (QVGA/CIF) resolution MPEG-4 video codec based on a low-power, general-purpose digital signal processor (DSP) (NEC μPD77210, 160 MHz, 80 mW, 1.5 V). To enhance video codec performance, the codec employs fast algorithms, including, in motion estimation, a successive similarity detection algorithm (SSDA; a fast block matching) whose decision timing for termination of block matching is optimized. Further, the use of a software direct memory access (DMA) queue reduces the wasteful DSP wait cycles that can result from massive access to external frame memories. The resulting codec executes QVGA (320 × 240 pixels) × 15 fps codec, or CIF (352 × 288 pixels) × 15 fps encoding at 384 kbps, in real time, performance levels sufficient for next-generation wireless videotelephony.