ATSC Modernizes Industry Audio Loudness Guidance With Revision To A/85 Recommended Practice
ATSC, The Broadcast Standards Association, has completed a major revision of its A/85 Recommended Practice: Techniques for Establishing and Maintaining Audio Loudness for Digital Television, marking the first comprehensive update to the industry reference since 2013.
The revision reflects more than a decade of technological evolution in television production, distribution and content delivery, providing broadcasters, equipment manufacturers, content creators and streaming providers with modern guidance for delivering a consistent, high-quality audio experience.
For years, ATSC A/85 has served as the industry's authoritative guidance for measuring and managing television audio loudness and has been widely used by broadcasters to support compliance with the U.S. Commercial Advertisement Loudness Mitigation (CALM) Act. More recently, the State of California has enacted a new law on commercial audio loudness for various Internet-streaming media services, mandating practices “consistent with the regulations adopted by the FCC pursuant to the CALM Act.”
The newly revised ATSC Recommended Practice modernizes the document with numerous technical clarifications and introduces two important new annexes:
- Guidance for establishing and maintaining consistent loudness for streaming media services using both metadata-based and non-metadata-based audio codecs.
- A new Loudness and True Peak Quick Reference designed to simplify implementation for engineers and content providers.
The revised A/85 Recommended Practice provides recommendations for audio measurement, monitoring, production, metadata management, dynamic-range control and loudness management throughout the content creation and delivery chain. By incorporating lessons learned from more than a decade of implementation, as well as addressing emerging streaming workflows, the document helps ensure consistent audio presentation regardless of how viewers access content.
The revision represents an important milestone for the broadcasting industry, as media organizations continue to transition toward IP-based and hybrid broadcast-broadband delivery models. Extending loudness guidance beyond traditional broadcast applications supports greater consistency for audiences while reducing operational complexity for organizations delivering content across multiple platforms.
You might also like...
The Changing Face Of Live Sports: Part 1 - The Rise Of Nimble Production
Live sports broadcasting has always been the preserve of big leagues and big broadcasters with the infrastructure, the clout and the resources to match. But it is no longer the only game in town.
Standards: Audio - High Efficiency Audio Codecs (HE-AAC)
HE-AAC builds on the foundations of AAC to deliver near CD-quality audio at bitrates as low as 32 kbps, making it the codec of choice for mobile TV, digital radio and low-bandwidth streaming. This guide unpacks the key technologies behind its…
IP Security For Broadcasters 2026 – The Psychology Of Security
As engineers and technologists, it’s easy to become bogged down in the technical solutions that maintain high levels of computer security. But as the boundaries between traditional broadcast engineering and IT continue to dissolve, the first port of call i…
Standards: Audio - Advanced Audio Coding (AAC)
AAC succeeded MP3 by delivering better quality at lower bitrates. This guide examines how it works, compares the leading encoder implementations, and explains where it sits within the broader MPEG audio standards landscape.
Broadcast Standards - The Science Of AI: New Foundations
We begin this series with the foundational building blocks of AI. Basic principles, the technology stack and the types of AI based upon it, and how to apply them effectively in a broadcasting enterprise.