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Taming TV Advert Audio


The last 18 months have been a busy and volatile time for all those concerned with the business of loudness in broadcasting. A comprehensive assessment of the state of this tricky subject was given at the Loudness Summit, held in London at the end of December, 2011.

The event was chaired by Florian Camerer, the senior sound engineer at Austrian public broadcaster ORF. Camerer was chairman and driving force of the EBU PLOUD working group that developed recommendation R128.

In his introduction, Camerer called loudness "the main audio topic of this time" but emphasized that with standards now established in different countries, the priority was to make both professionals and consumers aware of the subject in general.

Regulations are already in place in Italy. Although the German speaking countries, including Germany and Austria, have guidelines drawn up, they will not be implemented until September 1st.

France now has a "global" loudness alignment system, which was outlined by Matthieu Parmentier, innovations and developments manager for France Télévisions. Regulation began on December 19 and is compatible with R128, working to the target of -23 LUFS (Loudness Units relative to Full Scale). This system was agreed upon by all national broadcasters, advertisers and the CSA (Audiovisual Superior Council).

As Parmentier outlined, this consensus was reached after viewer complaints and several previous laws over the last 20 years, with the first law passed in 1986 and a second in 1992. France adopted ITU BS 1770, the basis for all other loudness recommendations, in 2008 and added Dolby Dialogue Intelligence. New loudness tools based on R128 were developed during 2010.

Under the 2011 law, all broadcast material -- including commercials, domestic programmes and bought-in English-language material -- has to adhere to strict guidelines. The regulations apply to distribution companies as well as broadcasters; anyone breaking them faces penalties of up to two percent of revenue. Parmentier explained that French broadcasters looked for a new standard as free-to-air HD services were being introduced and analogue TV was switched off.

Camerer called the French approach "a great role model" for broadcasters and regulators in other countries. But despite regulations being put in place and standards set, there is still uncertainty surrounding loudness in other countries. Camerer addressed this in his own presentation, Pitfalls and Misunderstandings About Implementation, which looked at the three areas that continue to cause confusion. These are target level; loudness range parameters, which he pointed out are not the same as dynamic range; and loudness pressure in the master control room and at output.

-23: Not a Loudness Sausage

The prime misconception appears to be that operators think a programme has to be at -23 throughout. Camerer dispelled this myth, saying the result would be a "loudness sausage" and demonstrated this with a tube-like audio waveform. "We encourage dynamic mixing," he said, explaining that the -23 target should be an average. Camerer observed that people should look at the subject on a macro, not a micro, basis and take a "bird's eye view" of a whole programme.

In his presentation, ‘Delivering Consistent Sound to the Consumer on Any Device, Any Time, Anywhere’, Tim Carroll, president and founder of Linear Acoustic, said audio quality was being jeopardized for the sake of compliance. It should be remembered that four important groups -- programme producers, broadcasters, regulators and consumers -- all had to be satisfied with what was transmitted, he said.

"Producers don't want the audio touched at all," Carroll explained. "Broadcasters don't want complaints and consumers don't want to be annoyed." He went on to discuss how different forms of delivery -- traditional TV, the Internet and mobile services --could complicate an already complicated subject. "We still have to think in terms of TVs with built-in speakers," he said, "but there are others with full bandwidth surround AV systems, and they are more likely to complain. Then there is the Internet, connected services and TV to mobiles. Broadcasters are faced with making four different versions and sending them all out, so there have to be accurate programme delivery specifications."

Carroll concluded that because viewers did not have meters they used their ears to determine what they liked; observing that "a happy consumer creates compliance".

Phil Greene, lead technologist with the BBC’s Technology Division, gave an insight into what the viewing and listening public did and did not like. In 2010 Greene was asked by BBC Audio and Music -- which oversees radio -- to assess the potential of adapting R128 for the broadcaster's operations.

During 2011, many complaints were received about the balance of dialogue or commentary in relation to music and/or effects on dramas and documentaries; both for radio and TV. Greene examined records of complaints for both media from the end of 2010 into the beginning of 2011. His findings, which he stressed were more of a straw poll and not backed by scientific proof, showed 60 percent of calls were about background noise on programmes. The remaining 40 percent of complaints was divided equally, with 20 percent concerning changes in volume from channel to channel and 20 percent about high dynamic range within programmes.

Randy Conrod, product manager for digital products at Harris Corporation, looked at ‘Loudness Management in Today's Systems’. Making the point that loudness is a "collision of biology and technology", Conrod said that "everyone hears differently"; a fact that depends not just on the kind of audio system being used at home but also on ambient/background noise and the listeners’ ages.

Conrod continued that although metadata was originally seen as the solution, with corrections taking place at the consumer end, the information could often be missing or incorrect. While dialogue normalization (dialnorm) was at the heart of systems like AC-3, he said, this could not be the only way of dealing with loudness, because there were different elements in the various programme genres; from drama to music to sport. "We have the tools and the training to deal with the problem -- and if something sounds wrong, it is wrong," Conrod concluded.

Peter Poers, managing director of audio processor and monitor manufacturer Jünger Audio, and Chris Hollebone, marketing manager for Merging Technologies, shared a session on ‘Real-time and File-based Analysis and Correction’; covering servers using data to handle MXF and loudness, integrated plug-ins, off-line loudness scanning and reporting and production chains. Hollebone observed that there are still many "old" TV sets still in use, so if a programme sounds good on those, it was well mixed. However, he said, there will always be a discrepancy between new shows and anything from the archive.

Distribution was covered by Richard van Everdingen, a consultant with Delta Sigma Consultancy in the Netherlands; as well as a member of the Dutch Broadcast Loudness Committee and leader of the Distribution Subgroup of PLOUD.

There are now many different types of services available to viewers, including public, commercial, regional and thematic broadcasts, video on demand services and cable channels through head-end operators, and van Everdingen acknowledged that loudness could be dealt with at any point in these chains. He added that at the end of this, domestic receivers could potentially undo what was done by the broadcaster or distributor.

"More stations are aware of what they are doing now," he said, "but there is a problem with set-top boxes. The money is there to get things right. Distribution companies know they need to do something but the problem is still there to be solved."

Jeffrey Riedmiller, director of Dolby's Sound Platform Group, looked at distribution alongside production and receiving devices in his presentation ‘End-to-End Loudness Control.’ Asking what is the purpose of loudness control, Riedmiller said the possible answers were stopping the phone from ringing with complaints; avoiding being fined by regulators; or reducing the need for the audience to mess with the volume control, which, he hinted, was the correct choice.

After looking at the different standards and technological methods for dealing with loudness, Riedmiller summed up by saying that "inter-programme level differences can and are being solved worldwide", with the best practice being to give the rendering device all information about the programme loudness.

Riedmiller also warned that if broadcasters, particularly at the local level in the US, did not adhere to recommendations, there was a risk of having "1975 sound" on modern TV audio systems. The critical thing, he said, was not to "over-bake" things as loudness was, in reality, extremely simple and the tools and solutions were now available to deal with it.