The purpose of our work is to produce a reference system that can simulate and calibrate degradations of speech and audio codecs which are currently used on telecommunications networks, for subjective assessment tests of voice quality. At first, 20 wideband codecs are evaluated through subjective tests with the general goal of producing the multidimensional perceptive space underlying the perception of current degradations. Then, from a verbalization task, it appears that the identified attributes are clear/muffle, high-frequency noise, noise on speech and hiss. Finally, these dimensions are characterized with correlates such as spectral centroid, spectral flatness measure, Mean Opinion Score and correlation coefficient.
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