The easy way

While prebuilt binaries are not yet available for all platforms, OCIO is available via several platform’s package managers.

Please note that the package managers are still installing the previous stable release, 1.1.1. If you want OCIO v2, you currently must build from source. See Building from source.

Fedora and RHEL

In Fedora Core 15 and above, the following command will install OpenColorIO:

yum install OpenColorIO

Providing you are using the Fedora EPEL repository (see the FAQ for instructions), this same command will work for RedHat Enterprise Linux 6 and higher (including RHEL derivatives such as CentOS 6 and Scientific Linux 6)

OS X using Homebrew

You can use the Homebrew package manager to install OpenColorIO on OS X.

First install Homebrew as per the instructions on the Homebrew homepage (or see the Homebrew wiki for more detailed instructions)

Then simply run the following command to install:

brew install opencolorio

To build with the Python library use this command:

brew install opencolorio --with-python

Building from source


The basic requirements for building OCIO are the following. Note that, by default, cmake will try to install all of the items labelled with * and so it is not necessary to install those items manually:

  • cmake >= 3.12

  • *Expat >= 2.2.8 (XML parser for CDL/CLF/CTF)

  • *yaml-cpp >= 0.6.3 (YAML parser for Configs)

  • *Imath >= 3.0.5 (for half domain LUTs)
    • *IlmBase (Half only) >= 2.4.0 (Alternative half implementation when OpenEXR 2 is available. Use -DOCIO_USE_OPENEXR_HALF=ON CMake option to enable).

  • *pystring >= 1.1.3

Some optional components also depend on:

  • *Little CMS >= 2.2 (for ociobakelut ICC profile baking)

  • *pybind11 >= 2.6.1 (for the Python bindings)

  • Python >= 2.7 (for the Python bindings)

  • Python 3.7 or 3.8 (for the docs, with the following PyPi packages)
    • Sphinx

    • six

    • testresources

    • recommonmark

    • sphinx-press-theme

    • sphinx-tabs

    • breathe

  • NumPy (for complete Python test suite)

  • Doxygen (for the docs)

  • OpenImageIO >= 2.1.9 (for apps including ocioconvert)

Example bash scripts are provided in share/ci/scripts for installing some dependencies. These are used by OpenColorIO CI so are regularly tested on their noted platforms. The script will install all dependencies for building OCIO documentation and is available for all supported platforms. Use GitBash (provided with Git for Windows) to execute this script on Windows.

Automated Installation

Listed dependencies with a preceeding * can be automatically installed at build time using the OCIO_INSTALL_EXT_PACKAGES option in your cmake command (requires an internet connection). This is the default. C/C++ libraries are pulled from external repositories, built, and statically-linked into libOpenColorIO. Python packages are installed with pip. All installs of these components are fully contained within your build directory.

Three OCIO_INSTALL_EXT_PACKAGES options are available:

  • NONE: Use system installed packages. Fail if any are missing or don’t meet minimum version requireements.

  • MISSING (default): Prefer system installed packages. Install any that are not found or don’t meet minimum version requireements.

  • ALL: Install all required packages, regardless of availability on the current system.

Existing Install Hints

When using existing system libraries, the following CMake variables can be defined to hint at non-standard install locations and preference of shared or static linking:

  • -Dexpat_ROOT=<path> (include and/or library root dir)

  • -Dexpat_STATIC_LIBRARY=ON (prefer static lib)

  • -Dyaml-cpp_ROOT=<path> (include and/or library root dir)

  • -Dyaml-cpp_STATIC_LIBRARY=ON (prefer static lib)

  • -DImath_ROOT=<path> (include and/or library root dir)

  • -DImath_STATIC_LIBRARY=ON (prefer static lib)

  • -DHalf_ROOT=<path> (include and/or library root dir)

  • -DHalf_STATIC_LIBRARY=ON (prefer static lib)

  • -Dpystring_ROOT=<path> (include and/or library root dir)

  • -Dpystring_STATIC_LIBRARY=ON (prefer static lib)

  • -Dlcms2_ROOT=<path> (include and/or library root dir)

  • -Dlcms2_STATIC_LIBRARY=ON (prefer static lib)

  • -Dpybind11_ROOT=<path> (include and/or library root dir)

  • -DPython_EXECUTABLE=<path> (Python executable)

To hint at Python package locations, add paths to the PYTHONPATH environment variable prior to configuring the build.

OS X and Linux

While there is a huge range of possible setups, the following steps should work on OS X and most Linux distros. To keep things simple, this guide will use the following example paths - these will almost definitely be different for you:

  • source code: /source/ocio

  • the temporary build location: /tmp/ociobuild

  • the final install directory: /software/ocio

First make the build directory and cd to it:

$ mkdir /tmp/ociobuild
$ cd /tmp/ociobuild

Next step is to run cmake, which looks for things such as the compiler’s required arguments, optional requirements like Python, OpenImageIO etc

For this example we will show how to install OCIO to a custom location (instead of the default /usr/local), we will thus run cmake with CMAKE_INSTALL_PREFIX.

Still in /tmp/ociobuild, run:

$ cmake -DCMAKE_INSTALL_PREFIX=/software/ocio /source/ocio

The last argument is the location of the OCIO source code (containing the main CMakeLists.txt file). You should see something along the lines of:

-- Configuring done
-- Generating done
-- Build files have been written to: /tmp/ociobuild

Next, build everything (with the -j flag to build using 8 threads):

$ make -j8

Starting with CMake 3.12, you can instead run a portable parallel build:

$ cmake --build . -j 8

This should complete in a few minutes. Finally, install the files into the specified location:

$ make install

If nothing went wrong, /software/ocio should look something like this:

$ cd /software/ocio
$ ls
bin/     include/ lib/
$ ls bin/
ociobakelut ociocheck  (and others ...)
$ ls include/
OpenColorIO/   PyOpenColorIO/ pkgconfig/
$ ls lib/
libOpenColorIO.a      libOpenColorIO.dylib

Windows Build

While build environments may vary between user, here is an example batch file for compiling on Windows as provided by @hodoulp:

@echo off

REM Grab the repo name, default is ocio
set repo_name=ocio
if not %1.==. set repo_name=%1

REM Using cygwin to have Linux cool command line tools
set CYGWIN=nodosfilewarning

set CMAKE_PATH=D:\OpenSource\3rdParty\cmake-3.12.2
set GLUT_PATH=D:\OpenSource\3rdParty\freeglut-3.0.0-2
set GLEW_PATH=D:\OpenSource\3rdParty\glew-1.9.0
set PYTHON_PATH=C:\Python27

REM Add glut & glew dependencies to have GPU unit tests
set PATH=%GLEW_PATH%\bin;%GLUT_PATH%\bin;D:\Tools\cygwin64\bin;%CMAKE_PATH%\bin;%PATH%

REM Add Ninja & jom to speed-up command line build i.e. one is enough
set PATH=D:\OpenSource\3rdParty\ninja;D:\OpenSource\3rdParty\jom;%PYTHONPATH%;%PATH%

call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x64
REM call "C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\VC\Auxiliary\Build\vcvarsall.bat" x64

set OCIO_PATH=D:\OpenSource\%repo_name%


echo %OCIO_PATH% does not exist
exit /b


echo *******
echo *********************************************
echo ******* Building %OCIO_PATH%
echo **
echo **
set are_you_sure = Y
set /P are_you_sure=Build in %CMAKE_BUILD_TYPE% ([Y]/N)?
if not %are_you_sure%==Y set CMAKE_BUILD_TYPE=Debug

set BUILD_PATH=%OCIO_PATH%\build_rls
set COMPILED_THIRD_PARTY_HOME=D:/OpenSource/3rdParty/compiled-dist_rls

if not %CMAKE_BUILD_TYPE%==Release (
set BUILD_PATH=%OCIO_PATH%\build_dbg
set COMPILED_THIRD_PARTY_HOME=D:/OpenSource/3rdParty/compiled-dist_dbg



echo **
echo **

REM cmake -G "Visual Studio 14 2015 Win64"
REM cmake -G "Visual Studio 15 2017 Win64"
REM cmake -G "Ninja"
cmake -G "NMake Makefiles JOM" ^
    -DPython_LIBRARY=%PYTHON_PATH%\libs\python27.lib ^
    -DPython_INCLUDE_DIR=%PYTHON_PATH%\include ^
    -DPython_EXECUTABLE=%PYTHON_PATH%\python.exe ^


REM Find the current branch
for /f %%I in ('git.exe rev-parse --abbrev-ref HEAD 2^> NUL') do set GITBRANCH=%%I

if not "%GITBRANCH%" == ""  prompt $C%GITBRANCH%$F $P$G

TITLE %repo_name% (%GITBRANCH%)

echo *******
echo *********************************************
if not "%GITBRANCH%" == "" echo branch  = %GITBRANCH%
echo *
echo Mode         = %CMAKE_BUILD_TYPE%
echo Build path   = %BUILD_PATH%
echo Install path = %INSTALL_PATH%
echo *
echo compile = jom all
echo test    = ctest -V
echo doc     = jom doc
echo install = jom install
echo *********************************************
echo *******
You could create a desktop shortcut with the following command:

%comspec% /k "C:\Users\hodoulp\ocio.bat" ocio

Also look to the Appveyor config script at the root of repository for an example build sequence.

Enabling optional components

The OpenColorIO library is probably not all you want - the Python libraries bindings, the Nuke nodes and several applications are only built if their dependencies are found.

In the case of the Python bindings, the dependencies are the Python headers for the version you wish to use. These may be picked up by default - if so, when you run cmake you would see:

-- Python 2.6 okay, will build the Python bindings against .../include/python2.6

If not, you can point cmake to correct Python executable using the -D PYTHON=... cmake flag:

$ cmake -D PYTHON=/my/custom/python2.6 /source/ocio

The applications included with OCIO have various dependencies - to determine these, look at the CMake output when first run:

-- Not building ocioconvert. Requirement(s) found: OIIO:FALSE

Quick environment configuration

The quickest way to set the required Environment variables is to source the share/ocio/ script installed with OCIO.

For a simple single-user setup, add the following to ~/.bashrc (assuming you are using bash, and the example install directory of /software/ocio):

source /software/ocio/share/ocio/

The only environment variable you must configure manually is OCIO, which points to the configuration file you wish to use. For prebuilt config files, see the Downloads section

To do this, you would add a line to ~/.bashrc (or a per-project configuration script etc), for example:

export OCIO="/path/to/my/config.ocio"

Environment variables

Note: For other user facing environment variables, see Environment Variables.


This variable needs to point to the global OCIO config file, e.g config.ocio


The lib/ folder (containing libOpenColorIO.dylib) must be on the DYLD_LIBRARY_PATH search path, or you will get an error similar to:

dlopen(.../, 2): Library not loaded: libOpenColorIO.dylib
Referenced from: .../
Reason: image not found

This applies to anything that links against OCIO, including the PyOpenColorIO Python bindings.


Equivalent to the DYLD_LIBRARY_PATH on Linux


Python’s module search path. If you are using the PyOpenColorIO module, you must add lib/python2.x to this search path (e.g python/2.5), or importing the module will fail:

>>> import PyOpenColorIO
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named PyOpenColorIO

Note that DYLD_LIBRARY_PATH or LD_LIBRARY_PATH must be set correctly for the module to work.


When building the OCIO OpenFX plugins, include the installed OpenColorIO/lib directory (where OpenColorIO.ofx.bundle is located) in this path. The path to a shared OpenColorIO lib (*.so, *.dll, *.dylib) should also be present on PATH.