Design, coding and processing of metadata for object-based interactive audio

For object-based audio, an appropriate definition of metadata is needed to ensure flexible playback in any reproduction scenario and to allow for interactivity. Important use-cases for object-based audio and audio interactivity are described and requirements for metadata are derived. A metadata scheme is defined that allows for enhanced audio rendering techniques such as content-dependent processing, automatic scene scaling and enhanced level control. Also, a metadata preprocessing logic is proposed that prepares rendering and playout and allows for user interaction with the audio content of an object-based scene. In addition, the paper points out how the metadata can be transported efficiently in a bitstream. The proposed metadata scheme has been adopted and integrated into the currently finalized MPEG-H 3D Audio standard.