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STREAMING: New Tools for the Optimal
by Jon Schorah
F or media companies steeped in
traditional workflows, the exploding
demand for over-the-top (OTT)
content on many different devices is offering
up significant new opportunities as well as
challenges. If content owners can re-purpose their assets
effectively, they can reach existing and new audiences
through channels that didn’t even exist. decade ago.
Although multi-screen video content is currently making
all the headlines, there’s also tremendous demand for
audio-only OTT programming ranging from music and
audiobooks to podcasts of popular radio shows.
Re-purposing audio for streaming and podcasting that was
originally mixed for broadcast is not for the squeamish.
There are key challenges related to audio quality and
listener satisfaction, not the least of which is intelligibility in
often less-than-ideal listening environments (think subway
cars and park benches). Other factors come into play, such
as the quality of the user’s ear buds or laptop speakers, or
lack thereof. Also, podcasts often utilize data compression
techniques in order to maximize the use of limited available
bandwidth, which can lead to distracting artefacts if
measures aren’t taken at the production stage. In this
article, we’ll discuss these challenges in more detail and
describe several new tools that were designed specifi cally
for re-purposing of audio over streaming services.
The Balancing Act: Exciting
Audio With Clear Dialog
One of the biggest challenges with audio re-purposing.
especially for podcasts. is to ensure dialog clarity while
reducing the dynamic range of material that was
originally mixed for. much more optimal sound
environment, such as home radio/TV or. cinema.
Programs with the highest dynamic range, i.e.
the widest difference between the softest and
loudest sounds, are consequently, some
of the most diffi cult to repurpose. Since
60 | KITPLUS - THE TV-BAY MAGAZINE: ISSUE 99 MARCH 2015
most people don’t listen to podcasts in the quiet of their
living rooms, ambient noise such as. passing subway train
or. blaring siren require the listener to turn up the volume to
hear the soft sections, which results in discomfort during
the louder sections. And, as we’ve mentioned, the wide
variation in the quality of playback equipment is. major
factor in the overall quality of the listening experience.
Podcast content with commercial breaks presents another
layer of complexity. In one loudness normalisation method,
an anchor element. most typically the human voice. is used
as. loudness reference. However, for the most exciting
mixes with the widest dynamic range,. variance exists
between program loudness and the average level of voices.
Depending on the balance of louder sections with average
voice level in. mix, the average voice level can drop within
the mix considerably after dynamic repurposing. Once
again, the viewer reaches for the volume knob to make
the spoken dialog more understandable. and interrupting
commercials that have been correctly set to programmed
loudness are now perceived as irritatingly loud.
Until now, the best way to address these challenges
has been to assign. mix engineer to remix the audio; i.e.
manually go through the mix and turn the volume up for
soft sounds and turn it down for louder sounds, however
not only is this process expensive and time-consuming, it
can be diffi cult to achieve. satisfactory result if the original
audio stems are not available and traditional compression
techniques are employed.
Loudness Normalisation Goals for Podcasts
One of the most important goals for content owners is to
maintain control of loudness normalisation, because if they
don’t do it, the OTT services will. Many steaming services
now employ loudness normalisation techniques (for
instance, Soundcheck for iTunes). If non-compliant audio
is submitted to these services, the resulting processing
can lead to transmission of audio that was not as originally