Dennis Ciapura /
01.01.2010 12:00 PM
Turn down the volume
Uncle Sam plans to control digital TV audio.

With all of the complexities of digital TV broadcasting, who would ever have thought that audio level control would become a national issue? It's become an issue so much so that the Commercial Advertisement Loudness Mitigation Act (the CALM Act, H.R. 1084) is inexorably inching its way through Congress and is expected to gain broad consumer support.

It's not as though this is a new issue. The FCC issued a Notice of Inquiry on the subject in 1962, a second notice in 1979 and an Opinion and Order in 1984. The perfect storm that has finally forced the situation to a head is the intersection of digital television's far greater audio dynamic range and the proliferation of high-quality 5.1 TV audio systems in the home as companions to the large-screen HDTVs that have been flying off the shelves.

Why digital audio is an issue

Dialnorm, the audio metadata protocol, was supposed to provide absolute level assignments to all sources, and in a perfect world, DTV audio level control would not be a problem. Commercials would be assigned appropriate levels compatible with surrounding program levels, and the Dolby decoders in the home would dutifully reproduce the desired level scaling. Unfortunately, as Gilbert Besnard pointed out in his article “Getting loudness under control” (in Broadcast Engineering December 2008), it is virtually impossible to preserve the original audio metadata through the complexities of production, storage, distribution and transmission in a modern TV plant.

Therefore, viewers with digital receiver outputs feeding 5.1 Dolby decoders are essentially getting raw audio, and most commercials are processed to produce consistently high average levels. They are intentionally loud. This is further exacerbated by the fact that many viewers are enjoying their 5.1 program audio at high levels, and when loud commercials hit, they really hit! Even before digital, and with significant analog program audio compression at the station, the inherent commercial loudness differential was prompting a regular stream of viewer complaints. And even with cable or satellite set-top boxes with additional audio compression enabled, many commercials still sound louder than the programming.

Government steps in

There are three major components to the commercial loudness problem. It's certainly a broadcast technical problem, but there's also a consumer electronics component as well as a growing political problem. Of these, the political aspect may be the most vexing. Broadcasters and advertisers loathe the idea of government intervention. The advertiser and ad agency perspective is revealingly reflected in a June 29, 2009, “Adweek” column by Robert Thompson, wherein he points out that “noisy and strident are part of the very foundation of advertising aesthetics.” Broadcasters obviously strive to super serve advertisers and the agencies, particularly in today's difficult economic environment with ever increasing shares of ad dollars going to alternative media.

But TV broadcasters can no longer ignore the reality of the pressure for a legislative remedy after 40 years of complaints. As Joel Kelsey of the Consumers Union stated in his June 11, 2009, testimony before the House Subcommittee on Communications, Technology and the Internet, 21 of the 25 FCC reports on consumer complaints since 2002 have listed loud commercials as a top grievance. Jim Starzynski of NBCU and David Donavan of MSTV provided effective testimony at the same session. They described the ongoing industry efforts to resolve the commercial loudness problem and requested that legislation not be moved forward pending the introduction of the new Recommended Practice for implementing the ATSC audio standard.

In late October, Starzynski presented a demonstration of how the Recommended Practice would work to subcommittee representatives, and although the demo was well received, it looks like H.R. 1084 is moving forward anyway. It has been amended to reference the Recommended Practice, but calls for the FCC to mandate its implementation. The original bill was clumsily based on “modulation” levels and maximum program loudness without reference to program length time integration, so at least the amended version would be based on meaningful industry-developed standards.

The ATSC Recommended Practice was introduced at an ATSC seminar on Nov. 4, 2009, and will be summarized in an article by Jim Starzynski in the March 2010 issue of Broadcast Engineering. This recommendation is the culmination of years of work by many of the brightest minds in the business and is intended to provide a path to effective commercial loudness control while maintaining the exciting program dynamic range that consumers have come to expect.

The reality is that in H.R. 1084, Rep. Anna Eshoo, D-CA, has a bill that almost nobody other than advertisers, TV broadcasters, cable and satellite operators would oppose. After all, how many representatives would like to explain to their constituents back home why they opposed a bill to stop loud TV commercials? And with consumer-oriented FCC chairman Julius Genachowski at the helm, it is expected that there will be effective enforcement.

The amended bill, which would be effective a year after passage, gives operators that can demonstrate hardship a one-year waiver with a possible one-year renewal, and this is a big loophole that many operators will jump through. This in turn will likely create an awkward mix of conforming and nonconforming outlets for some time, which may lead consumers to conclude that nothing much has changed, resulting in a continued flow of complaints to the FCC for years.

Understanding the technology

The least controllable element in the commercial loudness control challenge is consumer equipment in the field, and there can be some unexpected interactions with broadcast 5.1. For example, some commercials are not produced with 5.1 audio, but are transmitted as digital 5.1 with stereo audio “enhancement.” The receiver decoder senses the 5.1 digital input and applies whatever sonic processing the user has selected for normal 5.1 audio. This often results in phase-shifted mono or stereo audio that has an echo, which makes it louder than the surrounding program audio, even if the level is the same. In a mix with other commercials that have been properly encoded, this also creates a spot-to-spot differential.

And there are other anomalies. While most produced long-form programming these days comes with excellent 5.1 audio, local- and even some network-generated programs may lack true 5.1 capability. A convenient solution is to feed the available stereo audio to the left and right 5.1 channels. The problem with this is that home video/audio systems typically include a crossover to the subwoofer channel at 100Hz-200Hz. With no subwoofer input, the viewers get thin-sounding audio with the low end band limited by the crossover frequency. The subwoofer is essentially out of the picture — until a nice punchy compressed commercial comes along! In this age of sophisticated home video/audio, program producers and broadcasters must understand the technology that consumers are using.

Conclusion

The key to the successful implementation of the Recommended Practice, and heading off further government intervention, is in universal adoption. While the major networks and most major market affiliates can be expected to conform, the cable and satellite systems may lag. Local spot inserts in cable systems are a particularly weak point. These are usually local direct retail spots sold by local salespeople who are desperate to get their client's spots noticed. Hopefully, advertisers and their agencies at all levels will come to realize that the ATSC Recommended Practice is a far better solution than the viewer's mute button.


Dennis Ciapura is president of Performance Broadcasting, a broadcast management consulting company.

How to make your loudness comply

With or without additional government regulations, ATSC standards published back in the mid-1990s and adopted as the law by the FCC mandate that loudness be correct. If you didn't know that, you are not alone. There is no practical guidance as to how to make this happen. However, a new ATSC recommended practice attempts to distill a lot of information into one reference.

ATSC A/85 “Techniques for establishing and maintaining audio loudness for DTV” lays out a comprehensive plan for managing loudness from production to transmission. Essentially, it boils down to measuring content using an ITU-R BS.1770-compliant loudness meter to ensure that all audio either matches a loudness reference (-24 LKFS +/-2 ) or that the audio and corresponding metadata match. In either case, content that does not match can be rejected or adjusted, or metadata can be reauthored.

Guidance on both permanent and reversible dynamic range control is presented to help broadcasters understand the choices, and practical advice is given for setting monitor levels properly in production and post production so that an appropriate dynamic range will result during mixing and not be relegated to arbitrary adjustment later. A useful quick start guide is included to point readers directly to areas of interest.

What does a broadcaster need from the station side? At a minimum, you need a copy of A/85 and at least one real-time ITU-R BS.1770-compliant loudness meter to act as the station's DTV audio “mod monitor.” It may be wise to invest in more than one to allow monitoring of incoming content and to keep live productions in check. There's no need for mixers to worry; loudness meters work alongside the existing devices they are comfortable with.

Since the overwhelming passage of A/85 in November, broadcasters now have a reference to point to in their own delivery specifications and can send a clear and united message to program and commercial providers that they require loudness consistency in order to preserve audio quality, maintain legal compliance and most importantly satisfy viewers.

ATSC A/85 can be downloaded online at www.atsc.org/standards/practices.php.


Tim Carroll is the president and founder of Linear Acoustic.



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