Monitoring the Effects of Temporal Clipping on VoIP Speech Quality

This paper presents work on a real-time temporal clipping monitoring tool for VoIP. Temporal clipping can occur as a result of voice activity detection (VAD) or echo cancellation where comfort noise in used in place of clipped speech segments. The algorithm presented will form part of a no-reference objective model for quantifying perceived speech quality in VoIP. The overall approach uses a modular design that will help pinpoint the reason for degradations in addition to quantifying their impact on speech quality. The new algorithm was tested for VAD compared over a range of thresholds and varied speech frame sizes. The results are compared to objective Mean Opinion Scores (MOS-LQO) from POLQA. The results show that the proposed algorithm can efficiently predict temporal clipping in speech and correlates well with the full reference quality predictions from POLQA. The model shows good potential for use in a real-time monitoring tool.