The move to video over IP is inevitable. But when will the pros definitely
outweigh the cons?
Hello, and welcome to the fifth and final episode of Connecting OB: Discussing the
challenges of outside broadcasting. OB's are always being asked to do more. More
cameras, more slow-mo, higher resolution, higher framerate. But their size and
weight continue to be a limiting factor. Even with triple expanding sides it's
still a squeeze to fit everything in and still leave sufficient room for the
operators. Traditionally, an OB would have a large central SDI router. All the
cables running from the equipment into it. Alongside these cables would be these
reference distributions and yet more cables for the control. Using IT
technologies for routing and signal distribution offers advantages to the
truck designer. Firstly, the powerful IT switches necessary to route video are
physically much smaller and lighter than an SDI router, saving valuable space. Having a central
IT switch still means all the cables need to run back to one spot in the
truck, but I'm sure that as the technology matures distributed switching
systems will become more common, reducing the amount of cable. And this brings me
to my second point. The underlying IT connectivity is largely agnostic to the type
of data being transported. So video, audio, reference in the form of PTP or
precision-time-protocol and control can all be carried on a single, probably fiber, cable.
This greatly reduces the number of cables to be installed in a truck and
also the trucks weight. So here we see a central IT switch with single cables now
running from the equipment to it. A single cable from the control panel, and
more importantly, a single cable from the SPG carrying the reference signal. Of
course, using PTP to lock the equipment in an OB means there is no longer a requirement
to distribute separate reference signal. So this gains the truck designer more
space where the Black and Burst DA's would have gone. And talking about
reducing the number of distribution amplifiers, the IT switch is also the
signal distribution system. Nearly all of the equipment is connected to it and
therefore it is both switch and distributor in one package.
Another advantage of distributing video over IP is that both the connecting
cables and the switching devices are not limited to any video or audio format. Their
only real limitation is how much data can pass in a given time.
So assuming sufficient headroom has been allowed in the system,
there should be no reason to change the core infrastructure in a truck to
accommodate higher picture resolution, higher framerates, or increased color
space - or indeed all three. A lot of these connections will be based on fiber optic
cables, which are less resilient than copper, but there should now be sufficient
additional space within the OB to include some form of protection for
these cables. And as the IP system is data agnostic it is possible to use it to
carry other signals, such as the HDMI feeds into the multi-viewers, and also
to bundle signals together, such as video, talkback and queues, and send these
over long distances to the talent positions. So using video over IP will
solve a lot of problems, right? Well yes, but not all of them, and not right now.
there are still many hurdles to overcome. The common signal format being carried
in video over IP systems now is SMPTE 2022-6 which is simply SDI
packetized, sent over an ethernet link. You still need to de-embed the audio if
you need to use it, just like SDI. Other formats are being put forward such as TR-03
where the video, audio and data are carried in separate streams, but none of
them are really at the point where manufacturers are including them in
their equipment. And not all manufacturers have equipment that
currently works with S2022. So OB designs include a large number of SDI-to-2022
and 2022-to-SDI converters. And also some manufacturers have not adopted
PTP, so that although the signal is carried in video over IP, the reference
is still Black and Burst. A lot of the equipment is specified with 10 Gig E
connections, which means if you're going to use UHD which requires 12 gig, you
need to slightly compress the signal. There is no doubt that video over IP is the
future. Trucks are being built with an IT core but they also have a large number
of modular chassis full of converter cards. And the users are facing challenges in
cleanly and reliably switching the signals.
Yes, we're on the verge of a large change. But if you have to build a truck, think
long and hard before adopting this exciting new technology. Video over IP
offers many advantages to OB truck operators, both in terms of reduced
size and weight, but also in increased flexibility regarding signal standards
and ease of future upgrades. But think hard before committing to it right now.
Is this the right time to switch to video over IP? Join the discussion on
connectingob.tv or use the hashtag #connectingOB on Facebook, LinkedIn or Twitter.
Thank you for watching Connecting OB. We hope you've learned
from it and we'll see you next time.
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