Spatial Audio Processing: MPEG Surround and Other Applications

6.1 Introduction

Approximately half a century after the introduction of two-channel stereophony, multi-channel sound is now on its way into consumers homes as the next step toward more realistic audio reproduction. Initially, multi-channel audio was predominantly present in the movie domain on consumer media (DVD for example). The widespread availability of movie material with multi-channel sound tracks led to a fast penetration of multi-channel playback devices in consumers homes. Recently, probably in part due to the increased popularity of multi-channel movie material, the demand for a compelling surround experience has extended to the audio-only market as well (such as SACD and DVD-audio).

In contrast, the traditional broadcast services (such as radio and television) are still operating in stereo mode due to bandwidth and compatibility constraints. In audio transmission systems, the required bandwidth (or amount of information) of a six-channel broadcast would require approximately three times as much bandwidth as a conventional stereo broadcast. In many cases, this increased amount of information is undesirable or unavailable. Even if the increased bandwidth were available, the upgrade process of a stereo service to multi-channel audio should ensure that existing stereo receivers will still operate as before. With the existing technology, this means an even larger increase in bandwidth for simulcast of stereo and multi-channel audio.

In this chapter, the recently finalized ...