Personalization in object-based audio for accessibility : a review of advancements for hearing impaired listeners

Hearing loss is widespread and significantly impacts an individual’s ability to engage with broadcast media. Access can be improved through new object-based audio personalization methods. Utilizing the literature on hearing loss and intelligibility this paper develops three dimensions which are evidenced to improve intelligibility: spatial separation, speech to noise ratio and redundancy. These can be personalized, individually or concurrently, using object based audio. A systematic review of all work in object-based audio personalization is then undertaken. These dimensions are utilized to evaluate each project’s approach to personalisation, identifying successful approaches, commercial challenges and the next steps required to ensure continuing improvements to broadcast audio for hard of hearing individuals

Preferred levels for background ducking to produce esthetically pleasing audio for TV with clear speech

In audio production, background ducking facilitates speech intelligibility while allowing the background to fulfill its purpose, e.g., to create ambience, set the mood, or convey semantic cues. Technical details for recommended ducking practices are not currently documented in the literature. Hence, we first analyzed common practices found in TV documentaries. Second, a listening test investigated the preferences of 22 normal-hearing participants on the Loud- ness Difference (LD) between commentary and background during ducking. Highly personal preferences were observed, highlighting the importance of object-based personalization. Sta- tistically significant difference was found between non-expert and expert listeners. On average, non-experts preferred LDs that were 4 LU higher than the ones preferred by experts. A sta- tistically significant difference was also found between Commentary over Music (CoM) and Commentary over Ambience (CoA). Based on the test results, we recommend at least 10 LU difference for CoM and at least 15 LU for CoA. Moreover, a computational method based on the Binaural Distortion-Weighted Glimpse Proportion (BiDWGP) was found to match the median preferred LD for each item with good accuracy (mean absolute error = 1.97 LU ± 2.50)

Improving television sound for people with hearing impairments

This thesis investigates how developments in audio for digital television can be utilised to improve the experience of hearing impaired people when watching television. The work has had significant impact on international digital TV broadcast standards; it led to the formation of the UK Clean Audio Forum whose recommendations based on the research have been included in ETSI international standards for digital television, adopted into ITU standards for IPTV and also into EBU and NorDig digital television receiver specifications. In this thesis listening tests are implemented to assess the impact of various processes with a phantom centre channel and with a centre loudspeaker. The impact of non-speech channel attenuation and dynamic range control on speech clarity, sound quality and enjoyment of audio-visual media are investigated for both hearing impaired and non-hearing impaired people. For the first time the impact of acoustical crosstalk in two channel stereo reproduction on intelligibility of speech is quantified using both subjective intelligibility assessments and acoustic measurement techniques with intelligibility benefits of 5.9% found by utilising a centre loudspeaker instead of a phantom centre. A novel implementation of principal component analysis as a pre- broadcast production tool for labelling AV media compatible with a clean audio mix is identified, and two research implementations of accessible audio are documented including an object based implementation of clean audio for live broadcast that has been developed and publicly demonstrated

FascinatE newsletter 1

This FascinatE newsletter explains how gesture recognition will be used in the FascinatE system, how our first test shoot went at a Premier League football match, and explains about up and coming events

Intelligibility vs. comprehension : understanding quality of accessible next-generation audio broadcast

For traditional broadcasting formats, imple-mentation of accessible audio strategies for hard of hear-ing people have used a binary, intelligibility-based ap-proach. In this approach sounds are categorized eitheras speech, contributing to comprehension of content,or non-speech, which can mask the speech and reduceintelligibility. Audio accessibility solutions have there-fore focused on speech enhancement type methods, forwhich several useful standard objective measures of qual-ity exist. Recent developments in next-generation broad-cast audio formats, in particular the roll out of object-based audio, facilitate more in-depth personalisationof the audio experience based on user preferences andneeds. Recent research has demonstrated that manynon-speech sounds do not strictly behave as maskersbut can be critical for comprehension of the narrativefor some viewers. This complex relationship betweenspeech, non-speech audio and the viewer necessitate amore holistic approach to understanding quality of ex-perience of accessible media. This paper reviews pre-vious work and outlines such an approach, discussingaccessibility strategies using next-generation audio for-mats and their implications for developing effective as-sessments of quality

The clean audio project: Digital TV as assistive technology

Technology used in Digital TV has the potential to enhance the viewing experience for millions of hard of hearing people. The Clean Audio project commissioned by the Independent Television Commission (ITC), and continued by Ofcom, looks at methods by which the extra information contained in 5.1 surround sound broadcasts may be used to improve the intelligibility and enjoyment of television audio for hard of hearing viewers and shows that audio processing can effectively turn a digital TV set top box into an assistive device to make digital TV more accessible. Listening tests were carried out which showed benefits in clarity and in perceived overall sound quality for hard of hearing participants by altering levels of centre and left and right channels. Further testing has shown average improvements in intelligibility of up to 9.4% by using surround sound equipment with a discrete central loudspeaker compared to stereophonic reproduction

Clean Audio for TV broadcast: an object-based approach for hearing impaired viewers

As the percentage of the population with hearing loss increases, broadcasters are receiving more complaints about the difficulty in understanding dialog in the presence of background sound and music. This article explores these issues, reviews previously proposed solutions, and presents an object-based approach that can be implemented within MPEG-H to give listeners control of their audio mix. An object-based approach to clean audio, combined with methods to isolate sounds that are important to the narrative and meaning of a broadcast has the potential to enable users to have complete control of the relative levels of all aspects of audio from TV broadcast. This approach was demonstrated at the University of Salford campus in 2013