Method and system for high order conditional entropy coding utilizing an incremental-tree-extension technique to design a conditional tree for the coding. For complexity reduction, code table reduction and non-uniform quantization of conditioning symbols or pixels is provided. A pattern matching technique is provided for fast conditioning state extraction, and a multistage pipelined structure is provided to handle the case of a large number of conditioning pixels. Using the complexity reduction techniques and the hardware structures, it is possible to implement practical high order conditional entropy codecs using current low-cost VLSI (Very Large Scale Integration) technology.