BIRLE 1.0

BIRLE is a bijective Run Length Encoding (RLE) compressor implemented in Java.<br /><br />Like BIAC, it is another port of a compressor which was written by Mark Nelson and modified to make bijective by David Scott.<br /><br />I've modified it in such a way that it is no longer compatible with the original. I felt it was not conservative enough - and had too-great a tendency to cause expansion on perfectly normal files. As a consequence I changed it to consider a run as anything starting wiuth three repeated characters (rather than the original two).<br /><br />This modification increased the total compression ratio on the corpus from 11.49% to 12.72%. Increasing the run threshold further appeared to have deleterious results overall.<br /><br />This code is intended to act as a pre-processor for other compression schemes. It leaves the overall format of most files more-or-less intact (and just eliminates runs) leaving the floor open for subsequent compressors of different types.<br /><br />The improvement that can be expected is relatively small on normal files - but is increased if the files in question can be expected to contain many runs.<br /><br />For example, BIAC reduces the files in the corpus from 3,312,291 bytes to 1,841,675 bytes - a reduction of some 44.39%.<br /><br />If BIRLE is applied first, the reduction is to 1,821,284 bytes, making an overall compression ratio of 45.01%. The saving is of 20,391 bytes - or 0.62% of the total.<br /><br />There is a GUI front end as well as a command-line interface.

Requirements:	No special requirements
Platforms:	Mac, Mac OSX
Keyword:	Compressors,  Eliminates,  Floor,  Improvement,  Intact,  Leaving,  Subsequent,  Types
Users rating:	0/10