Objective Measurement of Perceived Auditory Quality in Multi-channel Audio Compression Coding Systems

Objective quality assessment methods have been used widely for evaluation of audio coding systems. However, even though many different competing multi-channel audio compression coding systems are being developed, most current quality assessment methods only predict results for monaural or stereo signals. In this paper, a prediction method is introduced that can be used for multi-channel audio compression coding systems. The method introduces three variables as measures of the degradations in spatial quality: interaural time difference distortion (ITD distortion), interaural level difference distortion (ILD distortion), and interaural cross-correlation coefficient distortion (IACC distortion). Simultaneously, ten Model Output Variables proposed in ITU-R recommendation BS.1387-1 are extracted from binaural signals that are synthesized using head related transfer functions. The prediction model is trained and verified using results from subjective listening tests of multi-channel audio compression coding systems that were performed by participants in the MPEG audio group. This new model, using the three interaural and ten non-spatial statistics, shows encouraging results in the prediction of perceived quality.