PPM compression without escapes

PPM compression without escapes

A significant cost in PPM data compression (and often the major cost) is the provision and efficient coding of escapes while building contexts. This paper presents some recent work on eliminating escapes in PPM compression, using bit-wise compression with binary contexts. It shows that PPM without escapes can achieve averages of 2.5 bits per character on the Calgary Corpus and 2.2 bpc on the Ca...

PPMexe: PPM for Code Compression

With the emergence of software delivery platforms such as Microsoft’s .NET, code compression has become one of the core enabling technologies strongly affecting system performance. In this paper, we present compression mechanisms for executables that explore their syntax and semantics to achieve superior compression rates. The fundament of our compression codec is the generic paradigm of predic...

Implementing the PPM data compression scheme

The “Prediction by Partial Matching” (PPM) data compression algorithm developed by Cleary and Witten is capable of very high compression rates, encoding English text in as little as 2.2 bits/character. Here it is shown that the estimates made by Cleary and Witten of the resources required to implement the scheme can be revised to allow for a tractable and useful implementation. In particular, a...

SPIHT image compression without lists

Data Compaction - Compression without Decompression

Data compaction is a new approach for lossless and lossy compression of read-only array data. The biggest advantage over existing approaches is the possibility to access compressed data without any decompression. This makes data compaction most suitable for systems that could currently not apply compression techniques due to real-time or memory constraints. This is true for the majority of all ...