The document discusses data compression techniques including lossless and lossy compression. It focuses on Huffman coding, a lossless compression algorithm. It explains how Huffman coding works by assigning variable-length binary codes to characters based on their frequency, with more common characters getting shorter codes. This allows the data to be compressed. It provides an example showing the construction of a Huffman tree from character frequencies and the assignment of codes. The codes generated satisfy the prefix property to allow for unique decoding.