CAM-based VLSI architecture for Huffman coding with real-time optimization of the code word table [image coding example]

Huffman coding is probably the best known and most widely used data compression technique. Nevertheless, the task of further decreased compression ratio through Huffman code up-dating in real-time is still a largely unsolved problem. In this paper, a novel architecture for CAM (content addressable memory)-based Huffman coding with real-time optimization of the code word table, called CHRC, is proposed. A CAM is exploited to implement fast Huffman encoding, and simultaneously the code word table is reconstructed and up-dated in realtime. The effectiveness of the proposed architecture is verified by structure, encoding flow and simulation results. The example of a JPEG application shows that our proposed CHRC method is able to achieve up to 40% smaller encoded picture sizes, and 6 times smaller clock cycle number for the encoding hardware than conventional Huffman coding methods.