An Efficient VLC for Lossless Data Compression: Leveling

Abstract

Many standard compression methods are based, at their most basic level, on coding digital words of variable length, or VLC, Huffman type, designed in 1952, or any of its variants, as canonical.  This article describes a VLC called "Leveling" that is more efficient than Huffman encoding and employs two variants: "Leveled Reordering" for low redundancy, such as text, and "Segmented Leveling" for moderate and high redundancy, such as image processing. Leveling, invented by Javier Joglar in 1995, employs the notions of "meaning" and "ordering" of the VLC codes generated to achieve the highest "compression ratio" of any non-adaptive VLC.