MHEG Activities
MHEG-5
MHEG-5 provides a robust, platform-independent environment for the implementation of interactivity in digital television. Applications are written as simple interpretable scripts and delivered to the receivers in a data carousel along with presentable objects like text and graphics. The application scripts run robustly on any conformant interpreter and do not interfere with the operating software of the receiver. Applications provide a series of scenes which display text and graphics and interact with the broadcast streams and the users through the remote handheld control. MHEG-5 also performs simple arithmetic and logic to provide a capability for local interactivity and games.
MHEG scripts can interact with broadcast video and audio streams, both displaying selected streams and performing actions based on timed events in the broadcast.
Test Suite
Following the announcement of the publication of the updated MHEG-5 UK Profile v1.06 in 2003, DTG Testing started a programme of work to develop the supporting test suite needed as the basis of conformance testing.
The work has been carried out by experts in the MHEG-5 arena, including BBC R&D, Cabot Communications, Sony and Strategy & Technology, as well as staff from DTG Testing itself.
The new Profile allows the development of well-characterised MHEG-5 engines through the removal of many of the ambiguities in the previous profile: it also extends the functionality of the MHEG-5 engines to make them more robust and allow more complex applications to be run. The more rigorous specification calls for an equally rigorous test suite and care has been taken to ensure that every item in the Profile specification is covered by at least one test in the new suite. Consequently the new suite contains about twice the number of tests in its predecessor.
An easy navigation system has been implemented to allow developers to access individual tests or to step through tests as required.
The new MHEG-5 Test Suite is available to product developers under licence from DTG Testing Ltd. A single licence covers one company. The suite is supplied in the form of transport streams with sample MPEG-2 audio and video files recorded on a CD-ROM for playing from a stream player.
For further details please contact DTG Testing Ltd (info@testing.dtg.org.uk).
MHEG engines
The Test Centre facilities enable it to carry out tests on MHEG engines embedded in receivers. The use of a DSM-CC carousel builder and multiplexer allows realistic test signals to be created.