The PAC originally developed by Elemedia, a subsidiary of Bell Labs, has a flexible format and bitrate. It provides efficient compression of high-quality audio over a variety of formats from 16 kb/s for a monophonic channel to 1024 kb/s for a 5.1 format with four or six auxiliary audio channels, and provisions for an ancillary (fixed rate) and auxiliary (variable rate) side data channel. For stereo audio signals, it is claimed that it provides near compact disc (CD) quality at about 56-64 kb/s, with transparent coding at bit rates approaching 128 kb/s. In the 1993, ISO-MPEG-2 5-channel test, PAC demonstrated the best decoded audio signal quality available from any algorithm at 320 kb/s, far outperforming all algorithms, including the layer-II and layer-III backward compatible algorithms.
Over the years PAC has evolved considerably. A known software implementation of this codec is CelestialTech's AudioLib Later, it was considerably improved and renamed to ePAC (enhanced Perceptual Audio Coder) by Lucent. It's available in the AudioVeda music library manager.
Signal processing, perceptual coding, and watermarking of digital audio; advanced technologies and models.(Brief article)(Book review)
Oct 01, 2011; 9781615209255 Signal processing, perceptual coding, and watermarking of digital audio; advanced technologies and models. He,...