Implementing real-time video processing systems put high requirements on computation and memory performance. FPGAs have proven to be effective implementation architecture for these systems. However, the hardware based design flow for FPGAs make the implementation task complex. The system synthesis tool presented in this paper reduces this design complexity. The synthesis is done from a SystemC based coarse grain dataflow graph that captures the video processing system. The data flow graph is optimized and mapped onto an FPGA. The results from real-life video processing systems clearly show that the presented tool produces effective implementations.