In this paper we propose an efficient implementation of CABAC's binary arithmetic coder and context management system. CABAC is the Context Adaptive Binary Arithmetic Coder used in new H.264/AVC video standard. Arithmetic coding allows a significant enhancement in compression. However, implementation complexity is a drawback due to hardware cost and slowness. In this paper we show the need for a hardware implementation of arithmetic coding in current video compression systems. We propose a fast and efficient implementation of the encoding algorithm. We prove that memory accesses constitute a bottleneck and propose solutions that apply to the encoding algorithm and context management system. As a result, a fast architecture is presented, able to process one symbol per cycle.