Pression  1.1.1
Compressor, decompressor, uploader and downloader plugins
Pression Documentation


Welcome to Pression, a C++ library for implementing and loading compression and CPU-GPU data transfer plugins.

The API documentation can be found on As with any open source project, the available source code, in particular the unit tests provide a reference for developing applications.

Technical questions can be posted to the Equalizer Developer Mailing List, or directly to

Commercial support, custom software development and porting services are available from Eyescale. Please contact for further information.


Pression provides the following major features:


Pression is a cross-platform library, designed to run on any modern operating system, including all Unix variants and the Windows operating system. Pression uses CMake to create a platform-specific build environment. The following platforms and build environments are tested:

  • Linux: Ubuntu 14.04, RHEL 6.6 (Makefile, Ninja)
  • Windows: 7 (Visual Studio 2012)
  • Mac OS X: 10.8 (Makefile, Ninja)

Building from source is as simple as:

git clone
mkdir Pression/build
cd Pression/build
cmake ..


On what basis where the compression parameters determined?

They are relative numbers when compared to the RLE compressor and the data compressed. Since both change over time with new compilers, CPUs and tested data, they are a somewhat arbitrary snapshot. Typically, all compressor parameters are updated when a new plugin is added on a representative visualization cluster node at the time. They are determined by running the tests/compressor benchmark which calculates them.