From a channel in many boxes to many channels in a box
(Broadcast Engineering Via Acquire Media NewsEdge) The last decade or so has seen a mushrooming of television
channels. Stations have added 24-hours news, sports channels, and
mobile channels to their multiplexes. The large content owners have
spawned movie channels and themed channels. But this explosion in
the number of channels has fragmented audiences. Although revenues
remain strong for prime networks, other channels look to minimize
operational costs. The demand for channels has driven down costs
for master control equipment, with vendors leveraging commodity IT
platforms. The lowering of costs has conversely enabled more
channels to launch, feeding the seemly endless demand for channels
to serve cable, satellite and IPTV viewers.
The old hardware-centric model of automation stems from the
early days where the need for realtime operation, with absolute
frame accuracy, naturally led to designs based around traditional
video processing: the master control switcher and separate video
servers and cart machines. The equipment was usually controlled via
RS-422 serial communications, supplemented with GPI triggers. An
automation chassis needed special cards with the requisite number
of RS-422 and GPI ports to drives switchers, video servers and CGs.
This interfaces are not a conventional IT component, and called for
bespoke designs just for the broadcast sector. The chassis also
needed a house timecode input for synchronization, again not a
commodity IT component.
Most equipment can now be controlled via IP over Ethernet,
removing the need for the interface cards. Even sync can use
Network Time Protocol (NTP) over IP. The end of the tape machines
removes the need to control the cueing of tapes, catering for the
ballistics of the transport. However, if the function of server and
switcher could be integrated into the automation computer chassis,
the need for all the control interfaces goes away. The remaining
issue is base-band video and audio. That needs a video card with
SDI in and out.
Channel in a BoxMuch of the recent marketing and development efforts in the
sphere of broadcast automation have been centered around the
“channel-in-a-box”. These products collapse the
functions of video server, switcher and graphics, along with the
playout automation, into a software application running on
commodity IT hardware with the I/O handled by a video interface
The issue is perhaps not the one box solution, but the fact that
software running on a computer server replaces dedicated broadcast
hardware like master control switchers and video servers.
Conflating functionality can save processes, as the external
communications and synchronization between devices are replaced
with more efficient interprocess communications within the
automation application. This means more bang for the bucks out of
The first step in the integrated solution was to combine the
automation with a video server and keyer using a commodity server
platform. The need for audio and video I/O led naturally to the
channel in a box, with the interface card occupying a PCI slot.
More channels means more I/O, and is it simplest to run each
channel on a single server.
Caution PrevailsBroadcasters are naturally reluctant to change their automation
systems. The revenue stream of the station, the commercial spots,
emanate from the automation system. Any stalled video, clipped
frames or other quality issues mean a makegood a direct loss
of revenue. So caution prevails.
As the processing power of computer servers has increased
radically over the last decade, it has become very possible to run
all the functions of a master control channel on a single IT server
chassis. As well as using the CPU, any vendors are also using
hardware acceleration from the graphics processor (GPU) and using
I/O cards with onboard video processing engines, with Matrox being
a popular choice.
NLEs have used commodity computer platforms since the 1980s, but
they use operations like pre-rendering of dissolves and effects to
save the load on the processor. They also use hardware acceleration
in all but the latest implementations.
Playout is different. Everything must be performed on the fly.
The defining factor for automation is whether the platform can
perform all necessary realtime operations within one television
frame. That way frame-accuracy can be achieved. However, some
operations present a varying load to the processor, graphics being
one. A poorly designed automation channel may run out of resources
during complex graphics sequences. During commercial breaks, the
only operation is to run each commercial, so the revenue stream is
protected, but the discerning eye may see stalling in graphics
interstitials. Over time Moore’s Law will eliminate this
No baseband?Many master control operations are playing out compressed files
from disk, or receiving MPEG files streamed from remote locations
in SMPTE 2022 format, RTP/UDP over IP. Such streams can be
delivered to the automation server over Ethernet, with no need for
conventional SDI interfaces. Where SDI interconnections are needed,
a gateway can link the baseband and IP domains.
To feed IPTV or mobile, there is no real need for SDI and the
goal of running a channel on a commodity IT platform becomes a
Disaster RecoveryIt is the wish of any channel with good revenue to provide
business continuity though any disaster that may prevent the
operation of the master control. Unusual weather events or
earthquakes are potential problems, or other disasters like fire
and floods. To provide a complete mirror of playout operations can
rarely be justified, but some compromise operations which keep the
brand running is perfectly possible. Cost is key for any disaster
The move to file-based operations has been the catalyst for more
broadcasters to consider the cost of setting up DR. The cost of
copying and transporting tape made DR operations very expensive,
but now files can be simply replicated to a site possibly thousands
of miles away, the economics have changed radically. A tapeless
operation, generating an MPEG transport stream become a wholly
software operation, with no need for baseband video.
Such a system could even be virtualized, running on a blade
chassis, maybe even in a private cloud. Using multiple multicore
CPUs deliver huge processing power. It becomes possible to run many
channels on a single server, currently 16 channels can be run on a
single machine, and number will increase. So we have truly moved
from a channel running on many boxes, to many channels in a single
box (see figure 1).
© 2012 Penton Media
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