Precomp, C++ version - further compress already compressed files
Branch: master
Clone or download
Latest commit c72b94a Dec 20, 2018


Join the chat at Build Status Build status

Packaging status

What is Precomp?

Precomp is a command line precompressor. You can use it to achieve better compression on some file-/streamtypes (works on files and streams that are compressed with zLib or the Deflate compression method, bZip2, GIF, JPG and MP3). Precomp tries to decompress the streams, and if they can be decompressed and "re-"compressed so that they are bit-to-bit-identical with the original stream, the decompressed stream can be used instead of the compressed one.

The result is a .pcf file (PCF = PreCompressedFile) that contains more decompressed data than the original file. Note that this file is larger than the original file, but if you compress it with a compression method stronger than Deflate, the compression is better than before.

Since version 0.4.3, Precomp is available for Linux, too. The Linux and Windows versions are completely compatible, PCF files are exchangeable between Windows and Linux systems.

How can I contribute?

  • You can have a look at the Issue list
  • You can build the project or download the binaries (see below), run it on your system and report bugs or make enhancement proposals.


Official GitHub releases for both Windows and Linux.

Alternative binary download of the latest official release for both Windows and Linux.

Binaries for older version can be found at this Google Drive folder.


Christian Schneider


To donate, you can either use the donate button on my homepage or send bitcoins to



Thanks for support, help and comments:

Legal stuff


Copyright 2006-2018 Christian Schneider

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.