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

For traditional broadcasting formats, implementation of accessible audio strategies for hard of hearing people have used a binary, intelligibility-based approach. In this approach, sounds are categorized either as speech, contributing to comprehension of content, or non-speech, which can mask the speech and reduce intelligibility. Audio accessibility solutions have therefore focused on speech enhancement type methods, for which several useful standard objective measures of quality exist. Recent developments in next-generation broadcast audio formats, in particular the roll out of object-based audio, facilitate more in-depth personalisation of the audio experience based on user preferences and needs. Recent research has demonstrated that many non-speech sounds do not strictly behave as maskers but can be critical for comprehension of the narrative for some viewers. This complex relationship between speech, non-speech audio and the viewer necessitate a more holistic approach to understanding quality of experience of accessible media. This paper reviews previous work and outlines such an approach, discussing accessibility strategies using next-generation audio formats and their implications for developing effective assessments of quality.