Assessing VOIP intelligibility in a low-connectivity environment

Abstract

Previous work has shown that telecollaboration is a suitable solution for remote assistance of industrial maintenance operations, provided that an audio chat solution is available. There are several reasons why audio chat may not be available: the quality of the available Internet network, both in terms of bandwidth and stability (jittering), but also the presence of too much noise at the site of the operation, which interferes with voice capture. This paper presents a methodology to evaluate the quality provided by an audio chat solution. This methodology is then tested on a specific audio chat solution built on a lossy compression algorithm based on the grouping of successive similar values to overcome the jittering problem and significantly reduce bandwidth requirements. We suggest evaluating the audio quality by assessing the intelligibility of different audio recordings using standard speech therapy methods. Our results suggest that an audio chat can be provided even in a low bandwidth scenario and in a noisy environment, which provides promising insights for the further development of telecollaboration. Moreover, the assessment of audio quality using restitution exercices to evaluate intelligibility, tested on a real use case gives interesting results on the usability of an audio chat solution as well as detailed feedbacks on which part of the altered signal is to be improved.