Patent ID: 8660261
Filing Date: 2014-02-25
Classification: H04N

Abstract:
1. An encryption-enabled entropy coder for a multimedia codec, comprising: a read-only memory (ROM) storing a single set of code tables, each code table being a code which maps a plurality of symbols to a plurality of codewords; a table lookup section coupled to the ROM, the table lookup section receiving an input bitstream containing a plurality of symbols, the table lookup section performing table lookup using the code tables stored in the ROM to convert the symbols to original codewords, the table lookup section further generating a codeword complete signal to indicate boundaries of the original codewords; and a table randomizer section coupled to the table lookup section for receiving the original codewords, an encryption/decryption key and the codeword complete signal, the table randomizer section converting the original codewords to randomized codewords based on the encryption/decryption key and the codeword complete signal using an isomorphic code generator algorithm, wherein each randomized codeword is an isomorphic codeword of the corresponding original codeword, the isomorphic codeword corresponding to a location in an isomorphic code tree which is identical to a location of the original codeword in an original code tree, the isomorphic code tree and the original code tree having identical topographies, the isomorphic codeword having identical length as the original codeword but having a different value from the original codeword.