Challenges converting between standards
“While some may argue the conversion from a newer standard to an old is a failure of the new standard, I would rather see the ability to convert as an important enabler for success during the introduction of a new standard.”
The work undertaken by DVB is very much about enabling new technology to be introduced in a structured and interoperable way – thus by definition it operates at the forefront of technology. But what happens during and after the introduction of a new standard? With my 20+ years of experience with DVB standards – primarily in the area of re-distribution – I have learned that a very clear indication a new standard is gaining acceptance is when requests for conversion start coming in: receive DVB-T2 and re-modulate to DVB-T, transcode HEVC into H.264, convert an HLS stream to DVB-C, to name a few. And what may come as a surprise is that those requests are not only for a transition period. Still, after more than two decades of digital television, development for PAL/NTSC modulation is very much active – only nowadays the content originates from a DVB-T2, HEVC 1080p source.
Why conversion matters
While some may argue the conversion from a newer standard to an old is a failure of the new standard, I would rather see the ability to convert as an important enabler for success during the introduction of a new standard. Most new DVB standards target direct-to-home applications, while requests for conversion are more from a business to business perspective. Often serving a larger number of end users, re-distribution – re-encryption, re-modulation, re-multiplexing, transcoding, etc. – is a more economically viable alternative than new end-user equipment. And if the conversion is possible, it will certainly be easier to find approval for a new standard from those businesses. Are these re-distribution scenarios well covered by DVB standards? Well, one of few places that mentions re-multiplexing is the document “Implementation and usage of Service Information”, known as DVB-SI, that simply states that “transitions with re-multiplexing” represent “the most complicated and expensive solution”, but provides no guidelines. This re-multiplexing has been basic functionality for even the smallest hotel installation for the past 15 years, so the statement may be somewhat inaccurate...
A related re-distribution functionality for hospitality is re-encryption. Content encrypted over satellite or terrestrial broadcast should, from the content owner’s viewpoint, still be encrypted when distributed in, for example, a hotel. There are several dedicated conditional access systems for hospitality provided by major TV set vendors, but to apply the new encryption the original broadcast obviously must be decrypted. CI+ is an excellent standard providing technology to ensure content is never exposed unencrypted, but the use case of re-encryption for hospitality is unfortunately disregarded. Alternatives include using a set-top-box combined with an encoder or using standard Common Interface. In both cases, the weak link addressed by CI+ remains exposed. CI+ is a success but had the redistribution use case been considered, adoption may have been even broader. DVB being a member-driven organization, there is of course no one to blame but ourselves. It is up to each company providing solutions for re-distribution to engage and ensure our use cases are considered, and I urge both partners and competitors to do so. But understanding the role of legacy formats is important for all of us, and it is my strong belief that awareness of the extent to which old standards are still being used is an important factor when defining new standards. And it will help us enable the introduction of all the forthcoming new fantastic DVB standards!
This article appeared originally in issue 56 of DVB Scene magazine [https://dvb.org/dvb-scene]