feature mobile TV
The idea of broadcasting to mobile devices has
been a hot topic in conferences and the press
for a few years now. But, with the exception of
the remarkably successful services in Japan and
Korea, there has been surprisingly little take-up
of the service. AAre Olafsen, headend segment
director at Grass Valley, reports.
Content to mobile:
the practical challenges
stories for broadcast, mobile and feed, would be cheering the result.hy has take-up been
online is already commonplace, for That is why we developed anso disappointing? I
example, and tools are now becoming automatic reframing system. It was asuspect the reason is
available to provide as much significant challenge, as it involvedthat the commercial
automation to this process as possible. developing a model of the way thatclimate - even
W
before the recent
With all of
News apart, consumers are likely to human vision works, then
economic meltdown - meant it was
the research
demand sport and popular drama on a implementing it in very fast software
difficult to develop a business case for
showing that
mobile service. Neither is likely to be so it can reliably detect the regions of
able to sustain dedicated production, interest in a moving video sequence,a whole new delivery service unless it
subscribers
because of cost in the case of the in real time, with very low latency.could be developed and operated
would only drama and because of practicalities in There are a number of ways in
cost-effectively, as an extension of the
existing headend architecture. consider the case of sport. Already there is which this region is detected. Salience
It also coincided with the rapid rise
mobile
pressure from sports bodies at the estimation looks for the parts of the
of high definition television.
television if
number of camera positions which picture with the greatest information
Production companies were learning a
the
broadcasters demand at big events: and rate of change of information,
asking for another complete set of which is what will attract the eye.new visual vocabulary, presenting the
perceived
cameras will not be warmly received. Sensitivity modelling emulates humanscene and allowing the viewer to
quality was So existing content has to be vision by detecting and giving greaterdiscover the action within the large,
high resolution picture. That works
good, it is
repurposed. In most cases, this will emphasis to image areas such as faces.
well on the new breed of large flat
clear that
involve reframing so that, on the small Having detected the regions of
screens which are proving so popular
simply
mobile screen, you appear to be much interest, you then have a number of
closer to the action. To do that processes you can apply. First andin the home: it does not work at all on
simulcasting
manually would require an operator- most obvious the system can zooma screen which is at most around
an existing intensive post production process. into it to create apparently tighter
80mm diagonal.
With all of the research showing programme, Again, the issue here goes beyond framing. This needs further
that subscribers would only consider
with the
cost. Yes, it would be an additional intelligence in the processing to
mobile television if the perceived
resolution
expense which we are trying to avoid, ensure that zooms and movements
quality was good, it is clear that
down-scaled
but more significantly it would take within the frame are smooth and track
time. The operator or team of the action in a natural way, rathersimply simulcasting an existing
for mobile,
operators would need to watch a than jerking around the frame.programme, with the resolution
was not sequence then run it again, tracking Second, the detected region ofdown-scaled for mobile, was not
going to be acceptable. Sport is not
going to be
the action to create the reframing. interest can be used to drive the
viewable if you cannot see the ball;
acceptable.
If you are watching a live sports encoder. Given that you have a fixed
event this could add minutes of delay bitrate in mobile television systemsdrama is not dramatic if you cannot
to the coverage, which would be (and most other applications) it makessee the faces.
unacceptable. You would be watching sense to bias the bit budget in favourSome dedicated content for mobile
the build-up to a piece of action while of the more interesting parts of thetelevision will need to be created. The
the person next to you, watching a text picture. In our example of sport on acreation of different versions of news
60 l ibe l september/october 2009 l www.ibeweb.com
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