Decoding and Compression of Channel and Scene Objects for Spatial Audio

Abstract

Sound fields can be encoded with a fixed number of signals, using microphones or panning functions. The sound field may later be reproduced approximately by decoding the signals to a loudspeaker array. The Stereo and Ambisonic systems provide examples. A framework is presented for addressing general questions about such encodings. The first problem considered is the conversion between encodings. The solution is applied to the decoding of scene encodings to a loudspeaker array. This is generalized to the decoding of subscenes where the resolution is focused in an angular window. Within an object-based audio framework such subscenes are useful for representing complex objects without using all the channels required for a full scene. The second problem considered is the compression of a scene encoding to a smaller encoding, from which the original can be reconstructed. The spatial distribution of compression error can be controlled.