Open-source DVB CSS libraries available

MATT HAMMOND, Lead Research Engineer, BBC R&D writes:

2-IMMERSE is seeking to enable the easy creation of multi-screen experiences. In doing so, one of the aims is to leave a legacy of re-usable technology solutions to the technical challenges encountered.

One such technical challenge is synchronising videos playing on different devices. Keeping those videos in-sync helps create the impression of a single unified experience. 2-IMMERSE has adopted a solution defined by DVB, known as DVB Companion Screens and streams (DVB CSS). This same solution has also been adopted by the HbbTV association which defines the interactive capabilities of TVs in many countries in Europe and beyond.

The BBC has previously developed an implementation of DVB-CSS in the Python programming language (pydvbcss). Now, working as part of 2-IMMERSE, they have developed a new version in the JavaScript programming language that is used across the 2-IMMERSE service prototypes.

This new version has now also been open-sourced, making it available for others to use. It takes the form of two software libraries that are available on GitHub and via the popular npm package manager:

• The dvbcss-clocks library (on GitHub and via npm) is a powerful way to represent timing and timing relationships.
• The dvbcss-protocols library (on GitHub and via npm) implements the protocols defined by DVB CSS to synchronise. It uses dvbcss-clocks to model the timing relationships between the devices being synchronised.

2-IMMERSE hopes that these libraries will be of use to anyone wanting to understand and use DVB CSS technologies in the future.