该文档详细描述了关于AAC音频的Huffman编码部分的两种隐写算法：码字符号位和码字空间映射。文档描述了算法的原理以及嵌入提取过程，并配有流程图以便参考。-

This document describes in detail the two hidden About AAC audio Huffman coding portion of the write algorithms: sign bit codewords and codeword space map. Document describes the principles and algorithms embedded in the extraction process, and with a flow chart for easy reference.