Apparatus and method for evaluating audio distorting

摘要

An improved apparatus and method utilizes both frequency and time masking effects to evaluate an audio distortions so that the results obtained thereby have a best match with actual human auditory perception. A power density spectrum is first estimated for an input digital audio signal and a frequency masking threshold is determined based on the power density spectrum for the input digital audio signal. In the meantime, a power density spectrum is estimated for a difference signal, wherein the difference signal represents the difference between the input digital audio signal and an output digital signal. A perceptual spectrum distance is then determined based on the power density spectrum of the difference signal and the frequency masking threshold. Finally, the audio distortion between the input digital audio signal and the output digital audio signal is estimated by multiplying the estimated perceptual spectrum distance with a weight factor calculated by using the power density spectrums of a current frame and its at least one previous frame of the input digital audio signal.