Skip to main content

ATSC revises recommended practices for audio loudness to support CALM

Members of the Advanced Television Systems Committee (ATSC) have approved new revisions to its “Recommended Practice A/85, Techniques for Establishing and Maintaining Audio Loudness for Digital Television” document. The revised version of A/85 includes a new annex entitled “Requirements for Establishing and Maintaining Audio Loudness of Commercial Advertising in Digital Television,” which is suitable for the FCC’s citation in its rules as per the Commercial Advertisement Loudness Mitigation (CALM) Act.

The CALM Act was enacted into law on Dec. 15, 2010, requiring the FCC to adopt the relevant portions of the ATSC A/85 standard. On May 27, 2011, the FCC released its Notice of Proposed Rulemaking as required by the CALM Act. The proposed rules apply to all TV broadcasters, cable operators and other multichannel video programming distributors (MVPDs).

The ATSC said its A/85 specification addresses audio measurement, production and post-production monitoring techniques, and methods to effectively control loudness for content delivery or exchange. It recommends methods to effectively control program-to-interstitial loudness, discusses metadata systems and use, and describes modern dynamic range control. This RP also includes specific information on loudness management at the boundaries of programs and interstitial content. ATSC Recommended Practice
A/85:2011, 25 May 2011, is the successor document to Recommended Practice A/85:2009, 4 November 2009.