Dirac is a new general purpose video compression system, suitable for resolutions from internet streaming to HDTV, that has been developed by the BBC. Dirac achieves state of the art compression performance and is expected to improve as it develops. It is a hybrid motion compensated codec that uses modern techniques such as wavelet transforms and arithmetic coding. The design of Dirac is intended to minimise complexity, thereby facilitating understanding and reducing the resources needed for implementation. Dirac is open technology, which means it is freely available and can be used without the payment of licence fees. Open technology is well suited to the business model of public service broadcasters. The open model of development adopted for Dirac supports open collaboration by anyone interested in its future development.