Standards:

> ITU-T
ITU-T Recommendation P.834, Methodology for the Derivation of Equipment Impairment Factors from Instrumental Models, 2002

This Recommendation gives a methodology for deriving equipment impairment factors (Ies) for digital signal processing devices, namely low bit-rate codecs. The Ie values are intended to be used as an input to the E-model [see also ITU-T Recommendation G.107]. The present methodology makes use of instrumental models (so-called "objective methods"), e.g. of the model defined in ITU-T Rec. P.862. It is to be considered as supplementary to the methodology based on auditory listening-only tests, described in ITU-T Recommendation P.833. It will provide valid Ie values only for those codecs for which the used instrumental model produces meaningful estimations.

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