N.J.—When we look at where television audio standards stand
today, it’s hard to reconcile the initial mono sound broadcasts from
television’s infancy to where it has evolved with the capabilities of
the next generation of broadcast standards, part of ATSC 3.0. This progression
of television audio from mono led first to stereo, then a second audio language
program (SAP), to ATSC 1.0 digital with the availability of Dolby AC3 Surround
Sound—each step advancing audio technology on a steady progression
towards making sound more realistic and engaging.
to the Next Generation TV Hub at the 2017 NAB Show check out immersive audio
Now, however, new doors are being
opened for content developers to leverage the ATSC 3.0 next-generation audio
standards and offer a more immersive sound environment, as well as provide end
users with a more personalized sound experience. An exploration of ATSC 3.0
audio standards capabilities demonstrates their impact on how we deploy and
engage with new sound systems that are evolving along with rapid advancements
in the digital world.
3D IMMERSION &
Building upon surround sound
that’s laid out in a plane (5.1)—such as with initial
surround sound systems like Dolby AC3—ATSC 3.0 audio standards take
sound to a full 7.1+4 implementation, meaning seven channels of sound in a
plane, one channel for a subwoofer (or the low frequencies), and four channels
On first look, this may just seem
like throwing more sound into the mix, but how that sound is delivered is what
makes it so unique. With audio experts having a detailed understanding of how
the ear works and how humans perceive sound, the new standards can be used more
effectively to convey directionality. And, what’s more, this can be
done not just on fully equipped home theater speaker systems leveraging all
channels, but on something as simple as a sound bar attached to a digital TV.
It’s even possible to replicate this immersive 3D sound environment
using ordinary headphones.
Imagine the sound of raindrops
hitting leaves over your head in a scene filmed in a tropical forest or the
oncoming sounds of a helicopter approaching from the side and crossing overhead
before moving on and away from you. The possibilities for sound technicians
truly are expansive and these new ATSC 3.0 standards involved are designed to
scale and accommodate newer, more sophisticated audio scenarios as they emerge,
making for a truly immersive 3D, and much more attractive, user experience
today and for the future.
While there’s likely to be
some time delay related to broadcasters implementing full capability of the new
standards, (as well as end users not running out to purchase advanced sound
systems), there are other aspects of the new audio technologies that are going
to probably be used right away, and that will ultimately be very impactful.
For example, the coding technology
for next-generation audio systems has moved away from being simply
channel-based systems. In today's 5.1 implementations, there are five channels
of surround sound and one channel for subwoofer, or low frequency, with fixed
assignments: front left, front right, center, the two rears, and then the
subwoofer. All sounds fall into these channels. Next-generation audio standards
additionally incorporate object audio, whereby audio objects can move and be
maneuvered into different positions to register sound information.
As an example, imagine someone
filming a skateboarder while they run a circuit in a skate park, where the
sound tech is following the skater using a joystick to control the movement of
a sound object in three dimensions. In this scenario, the sound will follow the
skateboarder around the course and record a more realistic representation of
sound as it changes with the skater’s movements. This allows for more
diversity as objects can be positioned and moved to accommodate a lot of unique
and intriguing audio scenarios.
Another change enabled by
next-generation audio standards—including audio objects instead of
just channels—is that it allows viewers to control and choose objects
that they want to hear (personalization). This enhances the user experience by
vastly increasing a viewer’s control over audio content. For example,
because you are dealing with objects, it makes it possible to offer controls
that allow viewers to turn one object up, or turn another down, based on their
own personal preference. For example, you might broadcast a football game where
one object is the home team announcer and the other is the visiting team
announcer. With next-generation audio systems, it’s fairly simple to
give the viewer control over the audio so that they can choose and customize an
audio experience tailored to their individual likes (choose which announcer to
listen to in this example). Another scenario might be a visually-challenged
viewer looking to “turn up” an object that is providing
some audio detail describing what is coming over the television screen (known
as descriptive video). Personalized audio is likely to be simpler to implement
than full immersive audio (especially regarding fitting into existing station
workflows) and will be very attractive to many viewers.
BUILT FOR THE
Technology is always evolving, as
are the capabilities of devices. Because it’s understood that
evolution will happen, ATSC 3.0 has been developed to gracefully move from what
we have today to what will be coming in the future. The need for this is
something learned from past experience and incorporated into the entire
standard, not just the audio portion. Throughout the entire system, each layer
signals to the layer above what technologies will be used. ATSC 3.0 has set the
stage for carrying both the old technology and new technology as it comes
online—a win-win scenario for all involved in broadcast television
and the viewing public at large.
In my opinion, one of the primary
themes of this years NAB was ATSC 3.0. ATSC 3.0 is clearly a
reality—with demos, products, conference sessions and significant
mention in the keynote speeches from FCC commissioner Ajit Pai, NAB’s
Senator Gordon Smith and Sam Matheny. There was a well-attended Next Generation
TV Hub in the LVCC Grand Hallway that demonstrated the reality of many new
features of the ATSC 3.0 system: Better Pictures, Immersive Sound, Mobility,
Gateway Devices, Targeted Ad Insertion, Audience Measurement, Emergency
Alerting, Content Delivery to Automobiles and a broadcast from Black Mountain.
The ATSC Pavilion in the Futures Park area of North Hall gave a deeper dive
into many technologies and features for ATSC 3.0—including the
systems currently being deployed in South Korea for the launch of UHDTV
services for the 2018 Olympics.
Dr. Richard Chernock is
the Distinguished Lecturer Chair for the IEEE Broadcast Technology Society
(IEEE BTS). He is currently the Chief Science Officer at Triveni Digital. In
that position, he is developing strategic directions for monitoring, content
distribution and metadata management for emerging digital television systems
and infrastructures. Dr. Chernock is active in many of the ATSC, SMPTE and SCTE
standards committees, particularly in the areas of future DTV, monitoring,
metadata, and data broadcast. He is chairman of the ATSC Technology Group on
ATSC 3.0 (TG3) and chairs the AHG on service delivery and synchronization for
ATSC 3.0. He was previously chairman of the ATSC Technology and Standards Group
(TG1). Previously, he was a Research Staff Member at IBM Research,
investigating digital broadcast technologies.
For more on this subject,
visit ourATSC 3.0 silo.