Datacasting Applications: Real World Experience

It is now a cliché to say that everything is becoming digital. This is particularly true for all broadcast media: satellite, cable and terrestrial. At the present time 75% of all satellite TV transponders are digital, and this ratio will soon reach 98%. The predominant, if not the only, standard for digital TV is MPEG-2. It was initially designed to carry video, audio and related data. But typically in an MPEG-2 Transport Stream, between 1 and 3 Mbps are unused and filled with empty or “null” packets. This represents a loss of at least $150,000 a year for a satellite transponder. As a consequence, MPEG-2 is more and more frequently being used to carry all kinds of value-added data. Internet Protocol (IP) is by far the most common way of carrying data; thus, the most sensible way of broadcasting data is to encapsulate IP frames into MPEG-2 packets. — So far, because of an early standardization process, most existing data casting applications are based in Europe. In this region “datacasters” can be classified in 3 categories: (1) Satellite operators (Astra, Eutelsat) who provide turnkey solutions to service providers, (2) Telecom operators (Belgacom, British Telecom, Deutsche Telekom, France Telecom, Telia) who provide professional services like corporate communications, distance learning, etc., (3) Broadcasters (Canal Satellite, Teracom, TPS) who inject add-value data as a complement to their digital TV programs. — Some use whole transport streams to carry their data, some use a constant part only and some others use the remaining bandwidth, injecting the data in an opportunistic way. Thomcast is by far the major supplier of IP to MPEG-2 gateways, thanks to its multiple award-winning product, Opal, based on OpenMux® technology. These experiences taught us several things: what are the most profitable applications, what pieces of equipment and software are needed in each case, and what functionality should an IP to MPEG-2 gateway and injection system provide. — This paper presents several European datacasting applications, the features that are important for our customers and gives an overview of how this can apply to the UNITED STATES terrestrial broadcast market.

Published

2001-02

Content type

Original Research

DOI

10.5594/M00352

ISBN

978-1-61482-934-8