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Immersive Sound: Mark Richer on ATSC 3.0 Audio

WASHINGTON—The next-generation broadcast transmission standard typically evokes discussions about mobile distribution and interactive functionality, but it will also include an emerging type of audio that places discrete sounds in a specific space. Think of it as all-around sound versus the 5.1 channels most often associated with surround sound. The Advanced Television Systems Committee issued a Call for Proposals last month for the ATSC 3.0 Audio Standard. ATSC President Mark Richer provided an overview of the developing standard in a back-and-forth with TV Technology’s Deborah McAdams.

TV TECHNOLOGY: How big of a departure does the developing ATSC 3.0 Audio Standard represent from broadcast audio as we know it?
RICHER: Immersive audio for ATSC 3.0 is composed of two different sound enhancements over the current ATSC 1.0 system; first, personalization and the ability to customize the audio program based on the viewer’s unique needs, environment or device and second, enhanced surround sound, bringing a much more enveloping experience to both the home theater and headphone listener.

Personalization includes enhancement to the control of dialog level, use of alternate audio tracks and mixing of assistive audio services, other-language dialog, special commentary, and music and effects. Plus, the system will support both the normalization of content loudness and contouring of dynamic range, based on the specific capabilities of a user’s fixed or mobile device and its unique sound environment. All of this is done in a much more bit-efficient manner than possible, if at all, by current DTV standards. Enhanced Surround will bring 7.1+4 to home theater enthusiast, supplying four overhead channels in addition to 7.1 surround.

TV TECHNOLOGY: The CFP includes stereo, 5.1 surround and 11.1 immersive. Are there speakers and systems that now accommodate immersive audio?
RICHER: At the 2015 CES, major consumer electronics companies were already demonstrating A/V receivers and speakers capable of immersive surround using a consumer version of already developed cinema technology. We know of plans for soundbars as well. 

TV TECHNOLOGY: Immersive audio for headphones? It sounds like an audiophile’s dream.
RICHER: Immersive surround on headphones is a requirement of the ATSC 3.0 system and can be a great sounding experience with the right content.

TV TECHNOLOGY: Is there a reason to expect TV manufacturers to enable immersive audio as much as they’ve embraced 4K resolution?
RICHER: Just as 5.1 surround sound is a an important part of the HDTV experience, immersive audio is a great complement to UHDTV (4K). 

TV TECHNOLOGY: The ATSC 3.0 Audio Standard Call for Proposals defines four receiver types: Fixed, handheld, vehicular and portable. How will these platforms affect the way broadcast audio is delivered?
RICHER: The ATSC 3.0 audio experience will adapt to the user’s unique needs and environment. The adaptive dynamic range control feature, just to name one, will be able to contour the range of a program to make sure the listener’s soundtrack is presented without the need to “ride the volume control” regardless of the listening devices capabilities or location.

TV TECHNOLOGY: This implies that tablet and smartphone manufacturers will add the necessary decoding chipset, correct? What stage is this in?
RICHER: : Consumer electronics will require a published standard before products are rolled out. The new 3.0 audio standard is still in the developmental stage. 

TV TECHNOLOGY: The CFP calls for “scalable” audio that’s responsive to reception conditions, connection speeds and device types. What’s the inherent challenge here?
RICHER: We are in the process of considering the benefits and challenges of scalability, which include efficiency versus complexity. Scalable coding could be used to provide a very robust base layer audio to all devices including TV’s tablets and phones. The enhancement layer could be used with the base layer to provide more sophisticated and complex audio services.

TV TECHNOLOGY: The CFP defines a “sweet spot.” Will I have to sit on top of the back of a chair in the middle of my living room to find it?
RICHER: All audio systems have a “sweet spot” where the listening conditions are optimal. New capabilities of the 3.0 system will enlarge the sweet spot and increase immersive soundtrack quality over a broad range of speakers that may not be placed in ideal locations.

TV TECHNOLOGY: Does the CFP define object-audio for broadcast TV?
RICHER: Objects are a method to increase the sonic elements of the soundtrack and minimize the necessary bandwidth to do so. A static object may be an additional language track or video description. Dynamic objects will contribute to the enhanced surround sound experience by eliminating “channel” restrictions. Objects—effects like a bird twitter or a canon blast—appear in precisely in the correct position in the sound environment regardless of where the speakers are located.

TV TECHNOLOGY:Is that a “yes?”
RICHER:We anticipate an accompanying Recommended Practice for audio that will describe best practices for the 3.0 audio standard. We would expect objects to be well defined in that documentation.

TV TECHNOLOGY: What else should we know about it?
RICHER: In addition to the features that have been mentioned, the ATSC 3.0 audio standard will be more efficient and robust compared to first generation DTV systems.

TV TECHNOLOGY: What is the timeline for completion?
RICHER: We expect the ATSC 3.0 audio Candidate Standard to be published in October of 2015.