Since the early 1990s, the Digital Video Broadcasting
Project has been working on developing open standards for digital video over
broadcast TV, satellite, cable and mobile. Today the not-for-profit consortium,
based in Geneva, has over 250 members -- broadcasters, equipment manufacturers,
network operators, regulatory bodies and others -- and its open standards are
widely used around the world, with more than 500 million DVB receivers
deployed. In this interview with HD
Update contributor George Winslow, DVB executive director Peter Siebert
talks about the development of its second-generation standards, DVB-S2, DVB-T2,
DVB-C2, which allow, among other things, for high-definition content to be
distributed much more efficiently over satellite, digital terrestrial and cable.
MCN: What are some of
the key things that your organization has been doing that relate to HD?
Peter Siebert: We
have done the second-generation standards for satellite, cable and terrestrial.
One of the main drivers for doing second-generation standards was that HD
content has become more and more the norm. So even when you have efficient
coding schemes, like H.264, you still have a higher data rate for HD, which means
you must provide a more-efficient scheme. That was one of the driving forces
behind the second-generation standards.
In addition, chip sets have become more powerful over the
last 10 years, new algorithms are now available and operators require new technical
features to support new business models.
The first second-generation standard we did was DVB-S2 for
satellite. It is being used on a worldwide basis for the transmission of high-definition
signal via satellite, but obviously can be used to transmit SD more efficiently
as well.
As we speak, the new terrestrial standard [DVB-T2] has been
implemented in the U.K. The set-top boxes are available and Freeview HD just
launched in March.
DVB-C2 has been the latest child of the family. It was finalized
in September of last year. Equipment is being made right now but is not yet on
the market. It typically takes a year or two after finalizing the standard for
the equipment to be announced.
European cable operators are looking into using C2 because
they need more capacity in the networks. So it is a very positive development
for cable operators because it provides improvement in performance and it gives
new flexibility.
C2 and S2 are so close to the theoretical limitations that
we don't expect to develop a 3rd generation standard. T2 [DVB-T2] still has
some options that could be used, but that will be for some later date.
MCN: You have also
been working on 3D?
PS: Yes, though
we are focusing on a specific segment in the overall transmission chain. We
focus at the input of the set-top box and we are working to specify the
necessary signaling so that, for example, a set-top box knows if a program is
2D or 3D.
That is what we are doing in the first phase of 3D. But
there will certainly be a second phase where we go beyond frame compatible
approach.
We expect the documents will be finalized on this by the end
of the year.
Of course, as I said, it is only a piece of the chain that
we are doing and other organizations are doing other parts of the chain. MPEG [Motion
Picture Experts Group] and SMPTE [Society of Motion Picture and Television
Engineers] will do coding, and HDMI [High-Definition Multimedia Interface] is
the interface. Then, of course, maybe one day, you potentially could have
standards for the displays.
Another area that we are focusing on for 3D is subtitles, so
that the set-top box needs to know where in the third dimension the subtitles
should be placed. This information must be transmitted to the set-top box, and we
are looking into how best to do this.
MCN: What
improvements will the DVB-C2 standard offer to operators?
PS: The C2
standard is a very interesting piece of technology that gives various
advantages and new features to the operators. First of all, it obviously gives
more capacity: typically, a 50% to 60% increase in capacity over DVB-C.
Second, it gives much more flexibility. In Europe, you have
8-Megahertz channels; in the U.S., you have 6-MHz channels, but the new
standard does not have a fixed frequency any more. So you can have very narrow
channels, only a few Megahertz, or you can have very big channels, which
basically would allow you to transmit 100 Megabits in one channel easily.
[DVB-C2 doesn't work] like DOCSIS 3.0, where you do channel
bonding to get 100 megabits. Here you really get -- on the physical level -- you
can get 100 Mb if you want to, or you can get very small channels.
This is a very important development for cable operators who
are competing with fiber to the home, because it means you can give very high
data rates to the end user.
The other important thing, which is a feature of all second-generation
standards, is that you can have different quality of service for different
services.
In the first generation of the standards, within one
frequency in satellite or cable channel, all services had the same modulation
scheme and the same forward error correction.
Now, within one frequency channel, we can define pipes and
each pipe can have a different modulation scheme and a different forward-error
correction. That means we can mix services with very different quality-of-service
requirements. For example, with T2 [DVB-T2 standard] you can have a high-definition
service that is transmitted to roof top antennas with a high data rate and very
stringent [quality-of-service] requirements, and you can mix it with a service
for portable television which has a lower data rate and a different [quality-of-service]
requirements.
MCN: How quickly do
you see your DVB-S2 standard being adopted for satellite delivery?
PS: S2 is very
successful in Europe already. It is just a guess, but there are for sure more
than 10 million set-top boxes for S2 in the European market, because the big
satellite operators in Europe have been combining S2 with HD. So, if you want
to receive HD, you need to have a S2 receiver. It is also being used in Asia. I
was in Hanoi in Vietnam two months ago, and Vietnam has 2 million subscribers
for S2 HD.
For the satellite operator, it is not a big investment. For
S2, you just have to change the modulator links. The main investment for
satellite is transponders and by changing the modulators they get 50% more
capacity on the transponders for HD and other services. So it is much more
efficient.
MCN: How quickly do
you see 3D progressing in Europe?
PS: I think you
have to look at two different camps. On one side, you have the pay TV providers,
who see third as a possibility to generate a new premium offer to their users
and get their users to pay extra money for a premium offer. On the other side,
you have the broadcasters who see the cost involved with 3D and have no means
to off load this cost to their customer because they are free to air.
So I think the pay TV operators have quite positive view of
3D. They are quite interested and keen to introduce new services and I think
they will watch Sky [in the U.K.] very closely to see how successful they are
with the service. If Sky is successful, I think they will jump on the bandwagon
whereas free to air broadcasters are a little more reluctant and are taking a more
wait-and-see position.
