Shannon-Fano Codes

This lecture introduces Shannon-Fano codes, a method for uniquely decodable and prefix-free coding. The instructor explains the definitions of uniquely decodable, prefix-free, and instantaneous codes, as well as encoding maps and trees. The lecture covers the Craft inequality and the existence of D-ary prefix-free codes. The instructor demonstrates the construction of a Shannon-Fano code for a given source distribution and discusses the optimality of these codes compared to the entropy. The lecture concludes by showing that Shannon-Fano codes are not optimal but provide a close approximation to the entropy, making them a practical choice for coding applications.