Dolby: Metadata, dialnorm important despite new consumer loudness control technology
By Ken Kerschbaumer
A new product introduced by Dolby at the Consumer Electronics Show designed to help viewers at home address the annoyances of inconsistent loudness in broadcast TV audio has stirred up concern among Dolby’s professional customers that the new technology will impact the way they should approach DTV audio signals and metadata.
But Dolby’s Rocky Graham, director of broadcast products, says that broadcasters need not worry. “We’re still completely behind the metadata system and behind our professional customers and development of professional products,” says Graham. “And the best way to provide the highest-quality signal is still by correct analysis of DialNorm parameters. When DialNorm is set correctly broadcasters will deliver the best overall quality signal.”
The new consumer Dolby Volume product is expected to be resident within TV sets and other consumer electronic equipment and, according to Dolby, models how humans perceive audio to eliminate variable loudness when changing channels or programs, without disruptive audio artifacts. The adjustments are automatic and do not require user intervention as the volume changes.
So, thus, the confusion and concern. “Some professional manufacturers have asked wheter Dolby Volume is going to be implemented on professional equipment. But you’re not going to see it in an Dolby Digital encoders or any professional audio equipment.”
Graham says that broadcasters should continue to work as if Dolby Volume doesn’t exist. First, Dolby Volume can be turned on and off. Second, the vast majority of consumer electronics devices in the market for years will not have the Dolby Volume feature.
“Dolby Volume is simply part of a comprehensive solution to the loudness issue,” says Graham. “It allows for loudness parameters to be placed around signals that are coming in that don’t have metadata. It can also be used on CDs, videogames, and analog TV signals as well as other digital TV signals. DBS, for example, till uses MPEG and has no metadata. So this is a way to address those issues.”
Tim Carroll, president of Linear Acoustic, says the damage may already be done. “Only 10% of viewers today listen to DTV with an audio-video receiver turned on, and that’s being generous,” he says. “So broadcasters might start asking that if 90% are listening through a TV that can control the audio levels why bother with metadata?” And Hollywood film studios, he adds, are outraged because Dolby Volume won’t differentiate between artistic and obnoxious loudness.
“We have always stressed that any audio processing is going to work better if it’s the creator who monitors the effects and levels,” says Graham.