Shannon–Fano coding
From Just Solve the File Format Problem
Shannon–Fano coding is an algorithm for constructing a bit-oriented prefix code, for use in data compression. It is analogous to Huffman coding.
From a file format perspective, most formats that purportedly use Shannon–Fano coding do not actually rely on any particular algorithm, so you can often think of Shannon–Fano coding as a synonym for Huffman coding. An exception would be if a format uses adaptive Shannon–Fano coding.
