This course gives an introduction to the perceptual, signal processing elements from which digital audio codecs are built:the human auditory system, hearing acuity, modeling of noise masking in human hearing & sound localization in space; filter banks, transforms, predictors, quantization & coding. Several aspects of audio perception that can be exploited for coding gain will be investigated:
the critical band structure of hearing, monophonic simultaneous masking, monophonic pre- & post-masking, stereo masking, lower acuity of hearing in the higher frequency band & perceptual
correlates to sound localization in a 3-D space. These principles will be illustrated by investigating several MPEG audio coding architectures: MPEG-1 Layer III (MP3), MPEG-4 Advanced Audio Coding (AAC), MPEG-4 High-Efficiency Advanced Audio Coding (HE-AAC), MPEG Surround, MPEG Spatial Audio Object Coding (SAOC) & MPEG Unified Speech & Audio Coding (USAC). Students will create a complete audio codec as a final project.