Demonstrations Show Off Potential of ATSC 3.0 Audio Standard
The two platforms vying to become the audio element for the ATSC 3.0 standard showed their stuff during a four-day demonstration exhibition in Atlanta in July. Dolby Labs (AC-4 ) and the MPEG-H Audio Alliance (MPEG-H) let ATSC members and other invited guests kick the tires a bit on their systems. The organization’s decision won’t be announced until fall, but, in the ATSC’s latest newsletter, ATSC TG3 Vice-Chair Skip Pizzi, who led the S31 Specialist Group on ATSC 3.0 System Requirements and Program Management, provides some insight into what went on.
Both proponents set up sophisticated and compelling demonstrations of their systems, showing how they would work in both professional broadcast facilities and consumer home environments. Pizzi, who is senior director, new media technologies, National Association of Broadcasters, served as audio-test coordinator, leading the testing and evaluation process of proposed audio systems for ATSC 3.0.
Explaining how ATSC 3.0 audio will be different from ATSC 1.0 audio, he says, “First, the stereo and 5.1-channel surround capabilities of today’s ATSC system will be expanded to include immersive (i.e., fully three-dimensional) sound using 12 or more channels. There will also be far more flexibility for broadcasters in the presentation of multiple languages, accessibility features, immersive sound elements and other effects through the use of audio ‘objects.’ Viewers will be able to personalize their TV sound experience by adjusting the level of dialog, changing the position of certain sound elements, changing dialog language, selecting different narration (like ‘home’ vs. ‘away’ announcers for sporting events) or adding commentary tracks, and so on.
“In consumers’ homes,” he continues, “the new system will accommodate a wide range of speaker and soundbar systems and placements and also include improved loudness and dynamic-range controls. Viewers will be able to merge soundtrack elements available on the Internet with broadcast content in perfect synchronization. And with all these and other features, the system will also be more bandwidth-efficient, so audio will require fewer bits in the payload. This means that these qualitative and quantitative improvements can be delivered to viewers in a highly practical manner, typically occupying the same or less bandwidth than today’s ATSC audio system requires.”
Pizzi further states that a number of chronic issues with broadcast audio, such as loudness management, will be better addressed via the new immersive-audio formats, using “intelligent” — that is, predictive versus simply reactive — loudness management and dynamic-range control.
The feature that consumers may come to appreciate most could be the dialog-enhancement feature that both formats offer, which will allow the user to adjust the level of the dialog track against the background sound. Collectively, these features could be used to keep announce tracks from getting lost in the swell of crowd and effects during moments of excitement in sports broadcasts, or they could allow viewers to dispense with the announcers altogether.
Other features include improved support for multilingual and video-description services and more-flexible methods of addressing the wide range of consumer audio-reproduction systems that exist, including headphones for mobile TV viewing, says Pizzi.
According to ATSC President Mark Richer, the demonstrations were useful in educating broadcasters and technologists who will use the formats. “Although most of the participants in the development of ATSC 3.0 were aware of our goals for a next-generation audio system,” he tells SVG, “they were impressed with the comprehensive demonstrations of the proposed systems.”
Pizzi sees the Atlanta event as a pivot point in the ATSC 3.0 audio process, one that moves it from testing to deliberations leading to a decision.
“While I can’t put a date when that process will conclude, it’s generally on track,” he says. “And following the audio technology selection, the Candidate Standard drafting should proceed fairly quickly. Ideally, a draft Candidate Standard for audio will be available sometime this fall.”