ITU-T P.880

This Recommendation describes a methodology called Continuous Evaluation of Time Varying Speech Quality (CETVSQ) that can be used for evaluating the impact of the time fluctuations of speech quality on the instantaneous perceived quality (that is perceived at any instant of a speech sequence) and on the overall perceived quality (at the end of the speech sequence). The method uses a two-part task: first, an instantaneous judgment on a continuous scale with a slider during the speech sequence, and second, an overall judgment on a standard five-category scale at the end of the speech sequence.