Subjective quality trade-offs in consumer multichannel sound and video delivery systems

EPSRC Project Reference: GR/N 24032
Start date: 1 December 2000
End date: 30 November 2003

Principal Investigator: Dr Francis Rumsey (Sound Recording)
Co-investigator: Dr Bart de Bruyn (Psychology)
Research Fellow: Dr Rafael Kassier
Research Fellow: Dr Slawek Zielinski
Industrial partners: Prof. Søren Bech, Bang & Olufsen, Denmark; David Meares, BBC Research and Development

Project Description

This three year interdisciplinary project is based in the Department of Sound Recording with additional supervisory input from the Department of Psychology. It is designed to study the effects of sound quality degradation on multichannel or 'surround' sound reproduction in consumer entertainment and broadcasting applications based on the recently adopted 5.1-channel or 3-2 surround format specified in ITU-R BS.775. In addition to providing valuable information to product designers and service providers concerning the audibility and relative importance of different quality degradations, the project will also enable the verification and trial of recently proposed methodologies for evaluating intermediate audio quality, such as that introduced by the EBU (European Broadcasting Union).

Perceptual models have been developed and standardised by the ITU-R (1999) that attempt, with reasonable success, to emulate the subjective response of human listening panels and produce 'mean opinion scores' for two-channel signals compared with an unimpaired reference (the so-called PEAQ system - for 'perceptual evaluation of audio quality'), but these models do not currently handle multichannel audio. The outcomes of the proposed work will inform any further developments of such models that may accommodate multichannel reproduction.

Numerous surround sound applications involve the use of moving pictures in some capacity (e.g. home cinema, digital television, multimedia applications), and it is proposed also to investigate the effect of video picture presence and absence on the judgment of sound quality. It is planned to evaluate how attentional conflicts between different sensory modalities influence the awareness of sound quality artefacts.