pydvbcss is a set of Python 2.7 libraries that implement some of the protocols defined in the DVB CSS specification "Bluebook A167-2". These protocols enable synchronisation of media presentation between a TV and Companion devices (mobiles, tablets, etc).
This library includes simple to use high level abstractions that wrap up the server or client behaviour for each protocol as well as low level code for packing and unpacking messages sent across the protocols. There are also objects that work with the rest of the library to represent clocks and timelines.
This code is intended as an informal reference and is suitable for building prototypes and testing tools that implement TV (server) or Companion (client) behaviour. It is not considered production ready or suitable for integration into consumer products.
The code does not implement media playback functionality and this is not a planned feature.
pydvbcss requires ws4py for use in clients and servers, and also cherrypy for server implementations. The steps below describe how to install these.
pydvbcss has been developed on Mac OS X 10.10 but has also been used successfully on Microsoft Windows 7 and Ubuntu 14.04.
The latest docs for the library can be read online here.
The master branch is the latest state of the code, including any recent bugfixes. It is mostly stable but might have occasional small API changes. Alternatively you can download a release snapshot.
On Mac OS X and Linux you may need to run one or more of the commands as root.
We recommend using pip to install dependencies from the Python Package Index PyPI:
$ pip install cherrypy
$ pip install ws4py
Then take (or update) your clone of the repository master branch, or
download and unzip a snapshot release and run the setup.py script to
install:
$ python setup.py install
This will install all module packages under 'dvbcss'.
There is a limited test suite (it only tests certain classes at the moment). Run it via setup.py:
$ python setup.py test
This checks some timing sensitive implementation issues, so ensure you are not running any CPU intensive tasks at the time.
There is a set of examples demonstrating simple servers and clients for the protocols included with the library. See the quick start guide in the documentation to see how to run them.
They demonstrate simple clients and servers. As appropriate, they pretend that there is content playing and that it has a progressing timeline. These examples serve to demonstrate how to use the library. They are not intended as finished and useful tools.
DVB has defined 3 protocols for communicating between a companion and TV in order to create synchronised second screen / dual screen / companion experiences (choose whatever term you prefer!) that are implemented here:
-
CSS-CII - A WebSockets+JSON protocol that conveys state from the TV, such as the ID of the content being shown at the time. It also carries the URLs to connect to the other two protocols.
-
CSS-WC - A simple UDP protocol (like NTP but simplified) that establishes a common shared clock (a "wall clock") between the TV and companion, compensating for network delays.
-
CSS-TS - Another WebSockets+JSON protocol that communicates timestamps from TV to Companion that describe the current timeline position.
The TV implements servers for all 3 protocols. The Companion implements clients.
There are other protocols defined in the specification (CSS-TE and CSS-MRS) that are not currently implemented by this library.
You can also build the documentation yourself. It is written using the sphinx documentation build system.
Building the documentation requires sphinx and the sphinx "read the docs" theme. The easiest way is using PyPI:
$ pip install sphinx
$ pip install sphinx_rtd_theme
The docs directory contains the configuration and main documentation
sources that descibe the structure. Most of the actual words are in the
inline docstrings in the source code. These structural pages pull these in.
To build docs in HTML format, either:
$ python setup.py build_sphinx
or:
$ cd docs
$ make html
Discuss and ask questions on the pydvbcss google group.
The original author is Matt Hammond 'at' bbc.co.uk
All code and documentation is licensed under the Apache License v2.0.
If you would like to contribute to this project, see CONTRIBUTING for details.