In Broadcast - October 2013 - 52

I N T E R N A T I O N A L

WWW.INBROADCAST.COM | ISSUE 24 - OCTOBER 2013

N E W S

InSOUND

Practical Loudness
Management
Jünger Audio provide some advice on integrating
a real-time hardware based loudness processor
into a transmission chain...

Jünger Audio’s T*AP loudness processor

T
52

he subject of controlling
loudness for TV transmission
has become more and more
important for broadcasters over
recent years. There are now
well established measurement
standards (ITU-R BS.1770-3),
recommended practices (EBU R128,
ATSC A/85 etc.) and a plethora of
tools, products and solutions to
deal with loudness at all stages of
the broadcast chain. These range
from production and ingest through
to play-out, both in the ﬁle based
and real-time domains. With so
many options, it can be confusing
to know how best to approach
the task of effectively managing
loudness in the real world of TV
broadcast.
Although it is widely accepted
good practice to get loudness
right as early as possible in the
chain, there are still many reasons
why a real-time processor just
prior to encoding for transmission
is desirable. In an ideal world, all
content would have either been
produced or normalised according
to the relevant recommendation
before it reaches the play-out
stage, but in the real world this
is not always the case. Content
received from external sources
may or may not be compliant and
good practice is, where possible, to
avoid re-processing content that has
already been normalised correctly.
In reality therefore, this means
switching the processor into different
operating modes depending on the

content status. For example:
• Loudness is known and is
compliant – Force the processor
into bypass mode;
• Loudness is known and is not
compliant – Force the processor
into ﬁxed gain normalisation with
True Peak Limiting;
Loudness is not known at all –
Force the processor into full dynamic
processing with True Peak Limiting.
Doing t his of course means
integrating the processor into the
broadcast scheduling or play out
automation system. With modernday loudness processors such as
Jünger Audio’s D*AP, T*AP or C8000
products, this can be easily achieved
in different ways. The simplest
way is external control via a GPI
trigger which is easy to set-up and
implement, but has limitations on
the number of triggers and therefore
parameters that can be addressed.
More comprehensive control can be
achieved by implementing an open
protocol such as L-S-B’s EmBER,
which is becoming an industry
standard for accessing individual
parameters across equipment from
different manufacturers and provides
a method of communication with
many of the play-out automation
systems in use today. The concept
relies on the automation system
holding information (Metadata)
about the loudness status and
generating flags to trigger the
processor into the desired state at
the appropriate point.

http://www.linkedin.com/pub/dir/?first=Phillip&last=Izzard&search=Go https://twitter.com/inbroadcast http://www.youtube.com/watch?v=qpzEatLsHdE&feature=youtube_gdata_player https://www.facebook.com/InBroadcast http://itunes.apple.com/gb/app/inbroadcast/id468652679?mt=8 https://play.google.com/store/apps/details?id=com.branded.inbroadcast&feature=search_result#?t=W251bGwsMSwyLDEsImNvbS5icmFuZGVkLmluYnJvYWRjYXN0Il0. http://WWW.INBROADCAST.COM http://www.cavena.com http://junger-audio.com/solutions/integrated-loudness/ http://www.cavena.com

In Broadcast - October 2013

Table of Contents for the Digital Edition of In Broadcast - October 2013