Abstract
This document describes breifly some of the terms and techniques that are used to describe and control the loudness and level of audio in broadcasting. Sometimes misunderstanding can occur because of loose or inaccurate use of terminology. The purpose of this document is to reduce that.
The kind of terms that are often used, are things like dB, dBFS, LUFS, LU, LKFS, dBu, dBm, V, alignment level, programme reference level, target level, dialogue level, loudness level, together with a range of "standard" numbers: 0.775, 0, -18, -20, -23, -24, -27, -31.
A description of dBFS, LU, LUFS, and related terms is given, together with an explanation of some of the common numerical values that are associated with measurements that use these units. Two methods of loudness normalisation using meta-data are briefly described and compared.
True peaks of an audio signal can exceed the highest sample value (the sample peak) when the signal is processed, potentially leading to clipping. Proper metering and control of levels is therefore necessary.
White Paper copyright
© ±«Óãtv. All rights reserved. Except as provided below, no part of a White Paper may be reproduced in any material form (including photocopying or storing it in any medium by electronic means) without the prior written permission of ±«Óãtv Research except in accordance with the provisions of the (UK) Copyright, Designs and Patents Act 1988.
The ±«Óãtv grants permission to individuals and organisations to make copies of any White Paper as a complete document (including the copyright notice) for their own internal use. No copies may be published, distributed or made available to third parties whether by paper, electronic or other means without the ±«Óãtv's prior written permission.
