By Vincent Grivet, chairman of DVB CM-T Group and vice president, broadcast development at TDF
For many years, radio and TV services could be delivered only via terrestrial transmitters. Despite the successful development of alternatives to terrestrial broadcasting, terrestrial transmissions still play an essential role in many markets.
However, the rapid evolution of digital technology and the media landscape could have far-reaching consequences. As a consequence, terrestrial broadcasting may need to be adapted to ensure that it will continue to bring the huge social benefits of an affordable, large reach and high quality access to media.
In order to develop standards and technologies one needs a sound understanding of the market and business context in which they will be used. DVB has developed a holistic vision of what terrestrial broadcast would likely be (or have to be) in the future to ensure that DVB specifications evolve in a consistent manner to achieve this vision.
A dedicated study mission, with participants from leading national and global companies and institutions, undertook this challenging exercise over the past year and arrived at some interesting conclusions1. The findings are based on a thorough review of the most important trends for change in the current environment (21 key context factors were identified) together with a survey from a large array of qualified worldwide experts, both inside and outside DVB.
Generally speaking, the DVB task force identified two main directions for change in terrestrial broadcast. Perhaps the most urgent and important one is to create the conditions where terrestrial broadcast can better ‘connect’ or adapt and serve the new media consumption paradigms. These include: the massive shift to on-demand viewing; the need to feed several different screens connected on a home network; the growing habit to consume media on mobile devices while on the move; and the trend to personalised media experiences.
Clearly there is much to be done to arrive to this point. It is not unrealistic to envisage that the power of terrestrial broadcast will have a role to play in the support of these new use cases. As a matter of fact, in many circumstances, unicast networks are facing or will face significant limitations such as capacity or coverage, which are less of a problem for broadcast based solutions.
The second axis for change is the need to plan further improvements in technical efficiency and performance of terrestrial broadcast technology. This is less of a priority as DVB-T2, the most recent terrestrial specification, when combined with the power of the emerging HEVC codecs provides enormous capacity and efficiency, and its full roll out is still ongoing.
And from a long-term perspective, improvements to performance will not be neglected. DVB has already carried out work that leads to promising possibilities in this direction. More precisely, a prospective study to quantitatively model the demand and supply for terrestrial broadcast capacities projected that a mid/long term gain of roughly a factor of 1,8 would be desirable to meet future demand with a drastically reduced supply as in the case of the re-allocation of 700 MHz band.
This growth in demand for capacity is fuelled principally by the overwhelming desire for higher image quality (HD and UHD) and the progressive emergence of new applications (eg. on-demand and mobile media delivery), which could take advantage of the wide reach and high efficiency of terrestrial broadcast. Thankfully this potentially large increase in demand can be mitigated by the high efficiency gains to be derived from deploying the latest DVB-T2/HEVC technologies.
In summary, the findings of the study mission point to the opportunity, and the need, for the continued contribution of terrestrial broadcast for the delivery of media to mass audiences. This can only happen with a determined collective effort of terrestrial broadcast stakeholders, including the DVB, to engage and deliver the necessary adaptations in line with the major changes that are taking place.
These changes are required to keep terrestrial broadcast as relevant as it is now, and has been for many years, for hundreds of millions of people. If this is not done with sufficient speed, there is a high risk of excluding equally huge numbers of people from the new media and digital services they are aspiring to enjoy.