The MPEG-DASH protocol has been rapidly adopted by most major
network content providers and enables clients to make informed decisions in the
context of HTTP streaming, based on network and device conditions using the
available media representations. A review of the literature on adaptive streaming over
mobile shows that most emphasis has been on adapting the video quality whereas this
work examines the trade-off between video and audio quality. In particular, subjective
tests were undertaken for live music streaming over emulated mobile networks with
MPEG-DASH. A group of audio/video sequences was designed to emulate varying
bandwidth arising from network congestion, with varying trade-off between audio
and video bit rates. Absolute Category Rating was used to evaluate the relative impact
of both audio and video quality in the overall Quality of Experience (QoE). One key
finding from the statistical analysis of Mean Opinion Scores (MOS) results using
Analysis of Variance indicates that providing reduced audio quality has a much lower
impact on QoE than reducing video quality at similar total bandwidth situations.
This paper also describes an objective model for audiovisual quality estimation
that combines the outcomes from audio and video metrics into a joint parametric
model. The correlation between predicted and subjective MOS was computed using
several outcomes (Pearson and Spearman correlation coefficients, Root Mean Square Error (RMSE) and epsilon-insensitive RMSE). The obtained results indicate that the
proposed approach is a viable solution for objective audiovisual quality assessment
in the context of live music streaming over mobile network.