The ITU Radiocommunication Assembly considering that conventional objective methods (e.g. for measuring signal-to-noise ratio and distortion) are no longer adequate for measuring the perceived audio quality of systems which use low bit-rate coding schemes or which employ analogue or digital signal processing; that low bit-rate coding schemes are rapidly being deployed; that not all implementations conforming to a specification or standard guarantee the best quality achievable with that specification or standard; that formal subjective assessment methods are not suitable for continuous monitoring of audio quality, e.g. under operational conditions; that objective measurement of perceived audio quality may eventually complement or supersede conventional objective test methods in all areas of measurement; that objective measurement of perceived audio quality may usefully complement subjective assessment methods; that, for some applications, a method which can be implemented in real time is necessary.