ATSC unveils standard guidelines for audio loudness

After more than two years of technical work, the Advanced Television Systems Committee (ATSC) has given final approval to a large document that establishes rules and suggests methods for dealing with audio loudness across television programming.

The new Recommended Practice (RP) offers broadcasters a document they have sorely needed. The networks all currently have different ways of controlling audio levels in the broadcast chain. Now, there should be little disagreement about how to keep a spike in audio level from a local car commercial to cause a viewer to change the channel.

The ATSC document represents a series of uniform operating strategies designed to eliminate or at least reduce disruptive changes in sound levels: mainly between commercials and TV shows. Now it’s up to the stations themselves to implement the recommended strategies or risk government intervention and possible technical mandates.

The “ATSC Recommended Practice: Techniques for Establishing and Maintaining Audio Loudness for Digital Television” was approved by the ATSC membership on Nov. 4, 2009, the same day the ATSC hosted a seminar on the topic of audio loudness at the Wiley Rein Conference Center in Washington, D.C.

The RP for controlling audio loudness gives guidance to broadcasters and creators of audio for HD or SD television content, and also recommends production, distribution and transmission practices for providing the highest quality audio soundtracks to digital television broadcasters. The document focuses on audio measurement, production and post-production monitoring techniques, and methods to effectively control loudness for content delivery or exchange.

In addition, the RP recommends methods to effectively control program-to-interstitial loudness, discusses metadata systems and use, and describes modern dynamic range control. It also includes specific information on loudness management at the boundaries of programs and interstitial content.

The Nov. 4 ATSC seminar — attended by members of the broadcasting, cable and satellite industries, as well as equipment manufacturers and consulting engineers — included presentations focused on the ATSC’s work on audio loudness. The program focused on related legislative activities and key topics such as industry outreach, real-world applications in audio, loudness measurement, monitoring, program interchange, interstitial loudness and metadata. Some of the presentations from the seminar are available online.

Presenters at the seminar included many of the same audio experts who worked for more than two years to develop the RP document. They included Pat Waddell (Harmonic), David Donovan (MSTV), Steve Lyman (Dolby), Graham Jones (NAB), Jim Starzynski (NBC Universal), Ken Hunold (Dolby), Tim Carroll (Linear Acoustic), Jim DeFilippis (Fox), Gregg Coppa (CBS), Sean Richardson (Starz Entertainment), and Adam Goldberg (AGP).

Dr. William Check, senior vice president, science and yechnology of the National Cable & Telecommunications Association, said the cable industry was involved with the ATSC development effort early on and that operators have said they will adhere to the recommendations laid out by the ATSC’s new document.

The IEEE Broadcast Technology Society, DaySequerra, Dolby, Junger Audio, Linear Acoustic, National Association of Broadcasters (NAB), National Cable & Telecommunications Association (NCTA), RTW, and Wiley Rein sponsored the audio loudness seminar. A/85 has been published on the Recommended Practices page of the ATSC Web site.