MPEG Unified Speech and Audio Coding

The MPEG Audio Subgroup has a rich history of accomplishments in creating music coding technology. At higher bit rates, MPEG technology can represent arbitrary sounds, including the human voice, with excellent quality. MPEG-1 and MPEG-2 Audio coders use perceptually shaped quantization noise as the primary tool for achieving compression. The MPEG-4 High-Efficiency Advanced Audio Coding (AAC) standard is a single technology capable of compressing speech, speech mixed with music, or music signals with quality that is always at least as good as the best of two state-of-the-art reference codecs, one optimized for speech and mixed content (AMR-WB B;) and the other optimized for music and general audio (HE-AACv2). This article provides an overview of the USAC architecture and summarizes the performance relative to the best state-of-the-art speech and audio codecs.