EUROSPEECH 2001 Scandinavia
7th European Conference on Speech Communication and Technology

Aalborg, Denmark
September 3-7, 2001


Instrumental Derivation of Equipment Impairment Factors for Describing Telephone Speech Codec Degradations

Sebastian Möller (1), Jens Berger (2)

(1) Ruhr-University Bochum, Germany
(2) T-Nova Deutsche Telekom Innovationsges. mbH Berkom, Germany

The impairment factor methodology has been adopted by the ITU-T for describing the relative impact of telephone transmission degradations on the overall quality of transmitted speech. Input parameters to this methodology are mainly instrumentally measurable characteristics of the transmission path, with the exception of low bit-rate codecs, whose perceptual characteristics still have to be determined in auditory tests. In this paper, we describe a new approach for deriving impairment factors for low bit-rate codecs in a purely instrumental way. Using instrumental quality prediction models like PESQ or TOSQA, quality estimations are obtained which can be combined with other degradations in order to obtain an overall quality estimation for the whole transmission channel. A comparison with defined values for well-known codecs shows a high correlation of instrumentally derived impairment factors with the corresponding defined values, as well as with auditory test data.

Full Paper

Bibliographic reference.  Möller, Sebastian / Berger, Jens (2001): "Instrumental derivation of equipment impairment factors for describing telephone speech codec degradations", In EUROSPEECH-2001, 1687-1690.