QVGA/CIF resolution MPEG-4 video codec based on a low-power and general-purpose DSP

This paper describes a QVGA/CIF resolution MPEG-4 video codec based on a low-power, general-purpose 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 DMA queue reduces the wasteful DSP wait cycles that can result from massive access to external frame memories. The resulting codec executes QVGA × 15 fps codec, or CIF × 15 fps encoding at 384 kbps, in real time, performance levels sufficient for next-generation wireless videotelephony.