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EBU nears end of work on loudness

The EBU working group on loudness is close to a breakthrough in its work on consistency of audio levels between different types of programme material, writes Kevin Hilton.

The EBU working group on loudness (some of its members pictured) is close to a breakthrough in its work on consistency of audio levels between different types of programme material, writes Kevin Hilton. Meeting in Vienna at the end of last week PLOUD “practically finished” the key Recommendation on loudness, R128, according to the group’s chairman, ORF audio engineer Florian Camerer. R128 is described as a short and precise description of how to monitor loudness and after nearly two years of work it is nearing finalisation. “There is only a tiny bit of wording to be done but the details of the bulk of the recommendation are finished,” says Camerer. The meeting in Vienna was attended by representatives from leading European broadcasters, including ORF (Austria), NDR (Germany), SSR (Switzerland), RTBF (Belgium), TSR (Switzerland), YLE (Finland), BBC R&D (UK) and TVP (Poland), together the EBU and the Dutch Loudness Committee. Manufacturers working in the area of loudness were represented by TC Electronic, Salzbrenner Stagetec, Dolby, RTW and Pinguin Engineering. Camerer comments that in a “textbook example of constructive collaboration” the companies had moved the EBU metering specification on to define the EBU Loudness Mode, a conformance point that covers interoperability between meters. The meeting also discussed the four technical documents that accompany R128. These are: Loudness Range, which describes how to compute R128; Loudness Metering, defining precise details for loudness meters, known as EBU Mode; Practical Guidelines for Production and Implementation, outlining the practical application of R128; and Distribution Guidelines, covering how material is distributed, with different levels for analogue and digital broadcasting, metadata and set-top box characteristics. Sub-groups of PLOUD discussed live production, post-production, file-based workflows and alignment, with overall agreement on a generic workflow for loudness levelling. Camerer says the workflow will be based on three descriptors: programme loudness, loudness range and maximum true peak level. “This will be adapted to specific areas like live production, post and file-based working,” he explains, “and we will build separate flow charts based on generic building blocks.” The hope is for PLOUD to complete all its work on loudness over the next four weeks, after which R128 will be submitted to the EBU Technical Committee for approval. Once that has been granted it will be published, together with four accompanying technical documents. Camerer says publication is planned for just before IBC 2010.