Can Objective Methods Replace Subjective Assessments?
Currently the only reliable method for evaluating the audio quality of low bit-rate audio codecs is by subjective assessments. This is a costly and very time-consuming procedure. Furthermore, existing coding standards are very flexible and allow for large differences in implementation without violating these standards. Thus, evaluations of individual implementations are necessary, but cost and efforts may hamper this. It is desirable that subjective assessments can be replaced, or at least complemented, by an objective measurement method. A number of proposals for objective perceptual models have been described in literature. At present, these methods are not sufficiently validated. In 1994, ITU-R established Task Group 10-4 to recommend a method for objective perceptual measurements of audio equipment. A draft recommendation is expected by the end of 1996. This paper reports on the work in ITU-R Task Group 10-4 and the requirements as outlined by the group. Experiences gained by the Swedish Broadcasting Corporation when using one of the proposed models, PAQM from PTT Netherlands, are also discussed.
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