Welcome to Coherence

-- Newsflash -- Stable version: Development version: 0.6.7 (github)


older news...

What is it?

For Users

The Coherence toolkit offers the following multi-media related components:

  • DLNA/UPnP Media Server (Coherence), which exports local files or online media to UPnP clients. There are many backends to fetch media from:
    • local applications media collections like those from Rythmbox or Banschee,
    • Audio-CD or DVB,
    • online services like Flickr, last.fm, YouTube, Picasa Web Albums and other.

Due to the comprehensive plug-in architecture, these can easily be expanded.

Coherence also contains an audio/video DLNA/UPnP MediaRenderer application, based on the GStreamer framework. It includes the source-code framework used by the other components. The media server supports Transcoding (experimental).

  • Coherence-Config is a cross-platform GUI frontend for 'Coherence'.
  • An image DLNA/UPnP MediaRenderer (Cadre), which can display pictures from the local filesystem or from a MediaServer.
  • An application level proxy for UPnP devices (Mirabeau) which allows to share your UPnP content between two or more local networks over the Internet. It uses XMPP as a transport (work in progress).
  • The UPnP-Inspector is a graphical UPnP Device and Service analyzer, and a debugging tool. Detected devices are displayed in a tree-view, where - amongst other things - actions can be called and state-variables be queried. It can also be used as a UPnP ControlPoint.
  • Plugins or extensions for other applications to open them to the UPnP world, thanks to the framework (either as MediaServers, ControlPoints or MediaRenderers). This includes Totem, Nautilus, Eye Of Gnome, Rythmbox, Banshee, Elisa, amarok...

If you are new to DLNA/UPnP you may want to read the Short Introduction to DLNA?.

Additionally there is a command-line tool to work with UPnP Internet Gateway Devices (Puncher). Many routers offer an UPnP InternetGatewayDevice to query informations about the WAN connection, the link status, external IP address and to enable port-mappings that allow inbound connections to the local LAN. Puncher allows you interacting with these devices.

The toolkit is known to work on various Linux flavors, BSD, (Open)Solaris and Windows. It can be installed either as a standard python source-code download or through various OS-specific packages.

For Application Developers

Developers get a framework written in Python with an emerging DBus API. This framework is designed to automate all UPnP-related tasks as much as possible and enable applications to participate in digital living networks, primarily the UPnP universe.

The core framework of Coherence provides:

  • an SSDP server
  • an MSEARCH client
  • server and client for HTTP/SOAP requests
  • server and client for Event Subscription and Notification (GENA)
  • A device implementation dock

UPnP device implementations are pluggable. For instance, we can pick the MediaServer device and plug it into the core. Or attach the MediaRenderer device. Or attach both, or two MediaServers and a ControlPoint - this is the point where one of Coherence's particular features kicks in.

This probably makes more sense if we look at how UPnP devices are implemented within Coherence. On one side of the device we have the connectors to the core, but on the other side there is a dock for a backend to be plugged in. So a device implementation is generally a simple translation map between the the core and its backend.

As an example, a MediaServer connects to the core via the ContentDirectory and ConnectionManager services and bridges them to a filesystem backend. Or bridges them - let's say - to a less skimpy one, the MediaStore? of a MediaCenter exposing its content in a way already presorted by album, artist, genre,...etc.

More information is available in the Architectural Overview.

Current State

At the moment Coherence is primarily focused on the UPnP A/V devices but any other UPnP device can be addressed, too. Such as a Lighting Controls bridge to EIB home-automation.

The core itself is fairly complete and can be used on its own for debugging purposes.

The media server includes an early implementation of transcoding support.

Supported Devices

Here is a list of devices which have been reported to work with Coherence. Please keep us informed about your devices.


  • Binary packages are available for various environments: they are listed on the packages page
  • Alternatively, there is an entry in the Python Package Index enabling you to install and upgrade with easy_install: easy_install Coherence
  • The source tarball for the current stable version is available here
  • Source checkouts via Git are possible too:
    • current stable release: git clone -b master https://github.com/coherence-project/Coherence.git Coherence-stable
    • current development head: git clone -b master https://github.com/coherence-project/Coherence.git Coherence

Any contribution (esp. pull-requests) is welcome.

Documentation & Hacking

For information about installation and using Coherence with(in) your application and writing backends and plugins, please visit the DocumentationDepartment and the slowly growing list of SupportedDevices.

For developing Coherence and the related projects we strongly suggest checking out the Development repository. It holds tools, tips and tricks, esp. scripts for setting up the development-environment.

There are also some posts about Coherence in my blog, these will sooner or later get incorporated into this site.

Contact and Discussion

  • Please add your bug-reports, suggestions, patches or comments as tickets to this trac instance
  • You may also add your feature requests here
  • You need to register first, to reduce spam.
  • Developers and users usually hang around on IRC: irc://irc.freenode.net/#coherence or irc://irc.freenode.net/#moovida
  • There are two mailing-list for Coherence:
    • coherence-announce: only announces about updates and new releases, read-only (Archive)
    • coherence-dev: discussions, questions,... about development and usage issues (Archive). For searching the history of the coherence-dev mailing list you can use Nabble.

Frank Scholz, the lead developer of Coherence, can be reached at dev@coherence-project.org.


Coherence has its roots in the work of


Coherence is licensed under the MIT license.


  • Coherence in written in Python, and currently tested against version 2.4, 2.5 and 2.6
  • depends on setuptools for the installation process and plugin management
  • profits from the excellent event-driven networking framework Twisted
  • needs ElementTree for its XML processing (included in Python 2.5)
  • uses Louie for signal dispatching (included in Coherence >= 0.5.8)

Optional Components


There are other projects that are similar to Coherence or provide related functions, such as a dedicated UPnP MediaServer implementation. They are listed on the Resources page.