The document discusses Huffman coding, a lossless data compression algorithm that uses variable-length codes to encode symbols based on their frequency of occurrence. It explains that Huffman coding assigns shorter codes to more frequent symbols for efficient data compression. The document provides details on how the Huffman coding algorithm works by constructing a binary tree from the frequency of symbols and assigning codes based on paths in the tree. It also discusses different types of Huffman coding like static, dynamic and adaptive probability distributions and provides examples to illustrate the adaptive Huffman coding process.