Control of Loudness in Digital TV

To facilitate better consistency between programs and stations, ITU, EBU and ARIB have investigated the standardization of broadcast loudness. This paper examines some consequences of a global loudness standard with regard to metering and control at the Ingest, Production and Transmission stages. Findings are reported from the latest research into mono, stereo and multichannel loudness measurement of real-world broadcast sounds. The improvements achieved by the new loudness models are quantified against previous level descriptors, such as, for example, PPM and Leq(A). Besides from reducing consumer annoyance with jumping levels, less engineering time needs being spent per audio stream. This too, is important because digital broadcast means a significant proliferation of the number of channels and the number of platforms. Each platform, such as TV, radio, internet, podcast, and other personal entertainment systems, has its own requirements for dynamic range, frequency range and speech intelligibility, so more automated handling is simply a necessity. The paper also introduces the term Dynamic Range Tolerance, DRT, which specifies the most desirable audio treatment for various broadcast platforms, and therefore is a practical tool for optimizing listener pleasure in digital broadcast. Examples of digital broadcast installations relying on static and dynamic metadata for loudness control are given. This paper is targeted radio and TV production, installation and management professionals. It provides user and technical info, and does not endorse or promote commercially available equipment.