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post #1 of 8 Old 11-09-2009, 12:27 AM - Thread Starter
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ATSC Sets DTV Audio Loudness Guidelines

By Greg Tarr -- TWICE, 11/6/2009

Washington - The Advanced Television Systems Committee (ATSC) said Thursday it has approved a recommended practice for establishing and maintaining audio loudness for digital television.

The recommended practice provides guidance to broadcasters and content producers on best production, distribution and transmission practices, for the highest quality audio soundtracks.

The document focuses on audio measurement, production and postproduction monitoring techniques, and methods to control loudness.

It also 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.

"High quality multichannel sound is an important element of the digital television experience," said ATSC president Mark Richer. "The new recommended practice provides the industry with uniform operating strategies that will optimize the audience listening experience by eliminating large changes in sound levels."

"The adoption of a recommended practice for implementing audio loudness culminates years of work by the ATSC. These efforts will benefit American consumers by resolving problems associated with loud commercials.' We look forward to working with ATSC to help television stations across the country implement this important decision," said David Donovan, president of Maximum Service Television (MSTV).

The guidelines were presented at a Nov. 4 seminar and included presentations focused on the ATSC's work on audio loudness, the ATSC said.

The program discussed related legislative activities and key topics such as industry outreach, real-world applications in audio, loudness measurement, monitoring, program interchange, interstitial loudness and metadata.

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post #2 of 8 Old 11-09-2009, 01:15 AM
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Originally Posted by Ken H View Post


It also 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.

It's about time. My local ABC affiliate jumps +/- 15-20dB going into breaks, news bumps and the like.
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post #3 of 8 Old 11-09-2009, 10:08 AM
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Originally Posted by Ken H View Post

The Advanced Television Systems Committee (ATSC) said Thursday it has approved a recommended practice for establishing and maintaining audio loudness for digital television.

They have finally published it on their website: http://www.atsc.org/standards/A_85.pdf
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post #4 of 8 Old 11-09-2009, 11:30 AM
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There is no station in the USA that fails as poorly as our local ABC KTRK. Their 5.1 is basically useless with these basic attributes:

1. Extreme harmonic distortion

2. Very muddy and muffled combined with a constant harmonic “beating”

3. Excessive and extreme “equalization” issues – peaks and valleys of +/- 20db or more.

4. Constantly and floating surround; such as all front left, all front right, etc. Never true 5.1 or balanced 5.1. Often music will blare out of rear speakers and the voices out of the front cannot be heard at all. “None” of Live Sports come through our local ABC 13-1 with functional 5.1 sound.


Less than 10% of the national feed commercials will come through that are understandable. Only about half the national news programs comes through in an understandable fashion. Virtually, all local generated sound sources are completely trashed.

The above only applies to the ABC HD 13-1. Their 13-2 which is 2.0 sound and 720p is fine.

The major issue with the ABC 13-1 we cannot watch the News, Primetime, or Live Sports on the Home Theater. Have to use the cheap TV’s with just plain crummy 2” speakers and 2.0 sound.


Our other local HD OTA stations put out excellent 5.1 sound. FOX and CBS are very close to HD quality sound. Crystal clear, Perfect EQ, zero distortion etc. Live sports is like being at the game! Music content shows are “real”. Most of those programs I use without compression, the dynamic range is stunning.
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post #5 of 8 Old 11-14-2009, 08:12 PM
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Maybe the ATSC document will help show broadcasters how to control their audio. The threat of legal action has scared many into finally taking care of this. Truth is, the rules have always been on the books. Lucky for them (and unfortunate for us) the FCC never bothered to enforce them!
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post #6 of 8 Old 11-15-2009, 12:51 AM
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We wouldn't have to buy new AVRs with Dolby Volume if they did. We just got done getting HDMI AVRs so they gotta keep the cycle going.
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post #7 of 8 Old 11-15-2009, 05:22 AM
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Originally Posted by hphase View Post

The threat of legal action has scared many into finally taking care of this.

Wrong. The "rules" you refer to only specifically refer to speech, not over all audio level. Audio in the digital world is much more complicated than just turning a volume control up and down. You can thank Dolby for that forcing AC-3, eh I am sorry, it is NOW called "Dolby Digital multichannel audio system for DTV" into the ATSC system. ATSC's new protocol answers many of the questions broadcasters have been asking for years. The biggest was to set a dialnorm standard for all to use. That has now happened with this new protocol, -24db. And to set which digital measurement standard to use, ITU's BS.1770.

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post #8 of 8 Old 11-15-2009, 05:27 PM
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Originally Posted by foxeng View Post

Wrong. The "rules" you refer to only specifically refer to speech, not over all audio level..

That is a typical misinterpretation of the existing rules. There is no loophole in the standard that implies that there is one rule for speech and another rule (or no rule) for everything else. If you were to do what the standard said -- set the dialnorm to the measured loudness of speech in the program or commercial -- you would have solved 90% of your problems.

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Audio in the digital world is much more complicated than just turning a volume control up and down. You can thank Dolby for that forcing AC-3, eh I am sorry, it is NOW called "Dolby Digital multichannel audio system for DTV" into the ATSC system. .

That is just "Oh,woe is me" hand-wringing. "This audio stuff is just too hard." The DTV audio system tried to be better than NTSC. Maybe no one wanted it to be...

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Originally Posted by foxeng View Post

ATSC's new protocol answers many of the questions broadcasters have been asking for years. The biggest was to set a dialnorm standard for all to use. That has now happened with this new protocol, -24db. And to set which digital measurement standard to use, ITU's BS.1770.

The document does NOT say what to set your dialnorm to. In addition to showing how to measure loudness, it says that dialnorm should be set to be the same value as the measurement. That is exactly what the standard said -- still says. You can't just set the dialnorm without measuring the program. The existing standard even says what algoritm to use. LA(eq), which is also an international standard. My guess is that the standard will be changed to specify the new BT.1770 standard. The end result will be the same for speech, and slightly better on the few commercials that don't have any speech.
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