Chapter 12 - Lossless Compression of Audio Data

Abstract

This chapter delves into lossless audio compression that is used to obtain the lowest possible bit rate while still retaining perfect signal reconstruction at the decoder. Lossless data compression of digital audio signals is useful when it is necessary to minimize the storage space or transmission bandwidth of audio data while still maintaining archival quality. As Internet is being increasingly used as a means to deliver audio content to end users for entertainment, the need to minimize the time required downloading an audio file and the expectations of end users with regard to signal quality, number of audio channels, and metadata provide incentives to compress the audio data. In the past decade, there have been significant breakthroughs in audio data compression using lossy perceptual coding. A plethora of bit resolutions, sample rates, and multiple channel formats are in use or have been proposed for recording and distribution of audio data. The essence of lossless data compression is to obtain efficient redundancy removal from a bitstream. The average compressed bit rate spec is most relevant for storage of audio files on computer hard disks, data tapes, and so forth, as this specifies the reduction in the storage space allocated to the file. In addition to the desire for the greatest amount of compression possible, consideration of the complexity of the compression/decompression algorithms and the feasibility of implementing these algorithms on the available hardware platforms is needed.