European digital TV standards body DVB has introduced a new, slimmed-down profile as part of the latest version of its next-generation DVB-T2 standard, targeting ‘low-capacity’ applications such as mobile broadcasting.
Known as ‘T2-Lite’, the new profile avoids processing- and memory-heavy modes, allowing more efficient receiver designs to be used – e.g. for a DVB-T2 tuner in a smartphone or tablet.
T2-Lite is limited to a maximum bit-rate of 4MBit/s, whereas the full HD-centric profile can run up to 48MBit/s (in the UK, DVB-T2 uses around 40MBit/s for DTT HD – see here.)
DVB says that “One possible use for T2-Lite enables the simulcasting of two different versions of the same service, with different bit-rates and levels of protection, which would allow better reception in fringe areas.”
According to a post on the BBC’s R&D blog, the BBC has been testing T2-Lite since July 7. In the trial, an HD signal for fixed reception and a T2-Lite version are combined within a single multiplex, with the T2-Lite frames placed in the gaps between the HD ones.
The concept that a single DVB signal could contain different versions of a broadcast which could be extracted by different receivers with different capabilities was proposed by the ‘god-father’ of DVB, Prof Ulrich Reimers, when DVB was originally set up, but has yet to prove popular in practice.
The BBC solution will be demonstrated at the forthcoming IBC exhibition in Amsterdam.