Describing Telephone Speech Codec Quality Degradations by Means of Impairment Factors
Sebastian Möller, Jens D. Berger · Journal of the Audio Engineering Society · 2002
The equipment impairment factor methodology adopted by the ITU-T for describing perceptual quality degradations associated with nonwaveform telephone speech codecs is discussed with regard to other degradations of the transmission channel. A new algorithm allows such factors to be calculated from the results of auditory tests, and first steps toward a derivation by means of instrumental models are presented. Limitations of the current approach for codec tandems are pointed out.