An architectural design of a media processor core optimized for MPEG4/H26x video codec targeted for use in mobile multimedia terminals is presented. The architecture consists of a maximum 6.4 GOPS SIMD (Single Instruction Multiple Data) processor, RISC-processor, VLC-processor, and intelligent DMA controller. The unique SIMD processor completes 2-D DCT processing in 132 clock cycles, or block matching (16 by 16 pixels) in 24 clock-cycles. VLC-processor allows the completion of 8 by 8 block run-level coding in average 10 clock cycles in the case of low bit-rates. The functions of transpose-registers in the SIMD processor, data sub-sampling technique in the DMA, or data-sliding technique between PEs (Processor Elements) in the SIMD processor eliminate a large amount of cycle loss for data handling, and extract the highest level of performance. Through the use of the above architecture and the lower power approach, CIF 30 frames/s MPEG4 Simple Profile video codec @ 100 MHz can be achieved. Estimated dissipation is as low as 280 mW. 300 kgates and 16 kBytes four port SRAM are contained on a 12 mm2 area by using 0.18 µm process technology. The combination of the RISC-processor and SIMD-processor can also operate MPEG4 core profile (shape coding) that requires flexibility and performance.