SMPTE 2011: Adding Mobile DTV at the Station
HOLLYWOOD: Mobile DTV will eventually need a differentiated
programming stream, but it probably won’t start out that way. That was the
assessment of Triveni Digital’s Dr. Rich Chernock, possibly the only
nuclear physicist working in TV.
Dr. Chernock started with viewing habits. Fixed ATSC viewing is typically by
appointment or DVR, and mainly full-show oriented. If device use is any
indicator, ATSC mobile viewing will be opportunistic, information-seeking, and
likely a mixture of short clips and full shows.
“What does this mean for mobile?” he said. “People will likely start by
simulcasting fixed content,” but separate schedules for mobile will likely
evolve for several reasons. ATSC fixed broadcasting is intended for large
screens. There are also creative considerations, demonstrated by the World Cup
broadcast over Europe’s mobile DVB-H standard, he said.
“A lot of times there you couldn’t figure out where the soccer ball was,” he
said. “Similarly, text or crawls may not be discernible on small screens.”
Audio is another reason to consider a separate stream. ATSC provides the
opportunity to do 5.1 surround sound. Mobile DTV is a different use case. It
will likely be used in a noisier environment. The speakers will be tiny
transducers or ear buds; amplifiers will be low power and sound will be stereo
or even monaural.
These differences need to be taken into account, he said. Pre-processing can
help alleviate problems. Certain elements of dialog can be isolated,
post-processing can be applied to adjust for conditions, and appropriate
downmixes can be used.
Interactivity ads a whole new quite of features and complications. Where do the
clicks land, for example. Servers are necessary to respond to interactivity.
Content management needs to be considered, along with scheduling, inserting and
a streaming timeline. There’s also “TV Mass Effect” to consider, where
interactivity overwhelms servers.
Security is yet another issue and a relatively new domain for most
broadcasters, Chernock said. Mobile DTV will require decisions about
subscription versus free, encryption, selection of a trust authority, customer
management and billing.
One thing about adding a mobile ATSC television service is that it’s unlikely
to require new listing, traffic, automation systems. With regard to
metadata--Triveni makes a PSIP and mobile metadata generator--it will need to
be managed for fixed and mobile reception. Chernock recommended adding mobile
signaling to use existing workflow components.
In summary, he said to consider people’s viewing habits, build on the existing
infrastructure, be aware of the requirements of interactivity and “use