On the Optimality of Binary AIFV Codes with Two Code Trees
Kengo Hashimoto, Ken‐ichi Iwata · 2021
Huffman code is the optimal code in the class of uniquely decodable codes in the sense of the average length of codeword when a single code tree can represent the code. This paper defines hierarchical subclasses of noiseless source codes by allowing$k$-bit decoding delay for positive integer$k$and clarifies a necessary and sufficient condition for the uniquely decodable codes with$k$-bit decoding delay. Furthermore, we show that AIFV code is the optimal code in the class of uniquely decodable codes with 2-bit decoding delay when two code trees represent the noiseless source code.