Assessment and Prediction of Speech Quality in Telecommunications

Is a Multi-Slider Interface Layout Responsible for a Stimulus Spacing Bias in the MUSHRA Test?

“…However, if a monadic method was used instead of the ACR procedure, the magnitude of some of the stimulus spacing effects might be reduced (A monadic method is a technique in which each assessor evaluates one and only one stimulus). This was empirically confirmed by Möller (2000) who applied the monadic test to speech quality assessment, referred in his study to as a "single stimulus rating conversation test". However, monadic tests are much more expensive and time consuming than the multi-stimulus tests.…”

“…This single-stimulus method would be similar to the absolute category rating (ACR) technique commonly used for speech quality assessment (ITU, 1996), with the exception that in the ACR method a discrete category scale is used instead of the continuous one. According to the literature, the ACR method is also prone to the stimulus context effects discussed above (Möller, 2000). Therefore, no substantial benefits in terms of a bias reduction are envisaged.…”

“…According to Möller (2000), the stimulus context effects can be classified into the three categories: (1) distribution effects, (2) order effects, and (3) anchor effects. The distribution effects, in turn, can be further divided using Poulton's taxonomy into centring bias, range equalising bias, stimulus frequency bias, and stimulus spacing bias (Poulton, 1989).…”

QoE beyond the MOS: an in-depth look at QoE via better metrics and their relation to MOS

“…As a result, we obtain an opinion score by interpreting the results on the rating scale numerically. An example is a discrete 5-point scale with the categories 1 'bad', 2 'poor', 3 'fair', 4 'good', and 5 'excellent', referred to as an Absolute Category Rating (ACR) scale [6].…”

A new QoE fairness index for QoE management

“…In QoE assessment, different rating scales are commonly used to assess quality, such as 5-point, 7-point, 11-point or continuous scales, which have different performance in terms of discriminatory power and reliability, and also differ in assessment time and ease of use by the subjects. As examples, Tominaga et al [43] discuss different rating scales for mobile video, Huynh-Thu et al [19] for high-definition video, and Möller [29] for speech quality. Moreover, the used QoE models may operate on different scales.…”