| commit | b3d3723f62e0ae088d38d9effaf3bd1d0b3acf21 | [log] [tgz] |
|---|---|---|
| author | Zoltan Szabadka <szabadka@google.com> | Fri Jun 12 16:25:41 2015 +0200 |
| committer | Zoltan Szabadka <szabadka@google.com> | Fri Jun 12 16:25:41 2015 +0200 |
| tree | dae7f929c88fc1ce3df4124dbc70ee466c18f86f | |
| parent | 94b337699f3cb27203c272415f3e780fc9e2de7e [diff] |
Add "zopfli"-style backward reference search to brotli. This commit adopts the backward reference search algorithm from the zopfli project (see https://github.com/google/zopfli) to brotli. This slower backward reference search is run only in quality 11 and it runs two iterations of entropy cost modeling and shortest path search. As a result, the original backward reference search function can be simplified a bit, since we can remove some heuristics that were replaced with the zopfli-style search.
Brotli is a generic-purpose lossless compression algorithm that compresses data using a combination of a modern variant of the LZ77 algorithm, Huffman coding and 2nd order context modeling, with a compression ratio comparable to the best currently available general-purpose compression methods. It is similar in speed with deflate but offers more dense compression.
The specification of the Brotli Compressed Data Format is defined in the following internet draft: http://www.ietf.org/id/draft-alakuijala-brotli
Brotli is open-sourced under the Apache License, Version 2.0, see the LICENSE file.
Brotli mailing list: https://groups.google.com/forum/#!forum/brotli