This paper presents a cost-effective platform architecture design for MPEG-4 video coding. A fast motion estimator architecture supporting predictive diamond search and spiral full search with halfway termination is implemented to make good compromise between compression performance and design cost. An efficient block-level scheduling for texture coding engine is employed to reduce the hardware cost. Both these key modules are integrated into an efficient platform in hardware/software co-design fashion. With high degree of optimization in both algorithm and architecture levels, a cost-efficient video encoder is implemented. It consumes 256.8 mW at 40 MHz and achieves real-time encoding of 30 CIF (352/spl times/288) frames per second.