Burrows–Wheeler compression: Principles and reflections

AbstractAfter a general description of the Burrows–Wheeler transform and a brief survey of recent work on processing its output, the paper examines the coding of the zero-runs from the MTF recoding stage, an aspect with little prior treatment. It is concluded that the original scheme proposed by Wheeler is extremely efficient and unlikely to be much improved.The paper then proposes some new interpretations and uses of the Burrows–Wheeler transform, with new insights and approaches to lossless compression, perhaps including techniques from error correction

Fast compression with a static model in high-order entropy

We report on a simple encoding format called wzip for decompressing blocksorting transforms, such as the Burrows-Wheeler Transform (BWT). Our compressor uses the simple notions of gamma encoding and RLE, organized with a wavelet tree, to achieve a slightly better compression ratio than bzip2 in less time. In fact, our compression/decompression time is dependent on Hh, the hth order empirical entropy. This relationship of performance to the compressibility of data is a key new idea among compression algorithms. Another key contribution of our compressor is its simplicity. Our compressor can also operate as a full-text index with a small amount of data, while still preserving backward compatibility with just the compressor.

Fast compression with a static model in high-order entropy

We report on a simple encoding format called wzip for decompressing block-sorting transforms, such as the Burrows-Wheeler Transform (BWT). Our compressor uses the simple notions of gamma encoding and RLE organized with a wavelet tree to achieve a slightly better compression ration than bzip2 in less time. In fact, our compression/decompression time is dependent on Hh, the empirical hth order entropy. Another key contribution of our compressor is its simplicity. Our compressor can also operate as a full-text index with a small amount of data, while still preserving backward compatibility with just the compressor.