About HisTV
HisTV provides a complete application framework for Handheld interactive synchronized TV based on DVB-H.
It was introduced first as MiTV on CeBIT 2005 and has proven it's functionality since then on many fairs and in many different live services on air. The HisTV Air Interface is published unter the Free Document License 1.2 and gives everybody the ability to provide conten, client and server applications. Everybody is invited to contribute and use HisTV to make interactive mobile TV happen very soon.
Features
Among all the features HisTV provides the following should be emphasized as the key features.
Layout
HisTV allows free layout of service by providing 255 possible rectangular areas on one screen - the ifields. Layouts have to be provided for both landscape and portrait orientation of the screen. The layouts refer to a QVGA resolution. Every ifield could show - synchronized - content based on bitmaps and text and react on clicks with a big choice of interaction possibilities either by local interaction or return channel interaction.
Synchronization
The content of the ifields could be synchronized to the video stream in areas of fraction of seconds. This makes applications like quiz shows possible, where a questions pops up in the exact same moment than the moderator is giving it to the audience but also subtiteling is very easy to implement.
Interaction
Interactivity does not necessarly mean to use the return channel all the time. By user feedback (through clicking on ifields) the application could change it's local content based on changing a state engine to a different state. The usage of the return channel for feedback, buying, voting and many other purposes is feasible by any mobile network using SMS or http requests.
Bandwith
The content for the ifields is transferred in very small chunks, the HisTV objects. This means, that only the actual scene representation has to be broadcasted together with the changes in the future of about 20 seconds. This leads to very low bandwith usage. A typical HisTV service eats up about 50kBit/sec in addition to the video signal. Although this bandwith is very low, the application starts at the same time than the video. There is no delay caused by a preload of huge amounts of data.
Robustness
The transport conventions and scene representation were developed with a strong view on stable function even in areas of bad reception. Even when objects are missed for the first time, they were broadcasted, the screen will refresh to a consitent view as soon as those objects are received.
Standards
HisTV tries to use as much of the existing standards in the DVB-H area as possible: FLUTE/ALC, AVC/H.264, NTP, http, sms... This makes client implementation easy as many existing applications like video players, browser, flute receivers could be reused and need not to be reimplemented again.