Method and apparatus for three-dimensional acoustic field encoding and optimal reconstruction

摘要

A method and apparatus to encode audio with spatial information in a manner that does not depend on the exhibition setup, and to decode and play out optimally for any given exhibition setup, maximizing the sweet-spot area, and including setups with loudspeakers at different heights, and headphones. The part of the audio that requires very precise localization is encoded into a set of mono tracks with associated directional parameters, whereas the remaining audio is encoded into a set of Ambisonics tracks of a chosen order and mixture. Upon specification of a given exhibition system, the exhibition-independent format is decoded adapting to the specified system, by using different decoding methods for each assigned group.

主权项

1. A method for encoding initial audio signals and related spatial information into a reproduction layout-independent format, the initial audio signals arising from any source of a plurality of sources, the method comprising:
defining a threshold directionality value to assign to one of a first group and a second group of one or more sources of the plurality of sources requiring localization; assigning a directionality coefficient to each source of the one or more sources; grouping sources with a directionality coefficient above the threshold value to the first group, wherein the first group of sources generate a first set of tracks of audio signals that require narrow localization and encoding the first group only as a set of mono audio tracks with associated metadata describing the direction of origin of the signal of each track with respect to a recording position, and its initial playback time; encoding individual audio tracks of the first group with the associated metadata to facilitate playback through a minimal number of loudspeakers about an intended location of each respective source of the first group; grouping sources with a directionality coefficient equal to or below the threshold value to the second group, wherein the second group sources generate a second set of tracks of audio signals that do not require narrow localization and encoding the second group as at least one set of Ambisonics tracks of a given order and mixture of orders; and encoding in the metadata, spread parameters associated to each source of the first group, wherein a value between 0 and 1 describes an angular width of a recorded sound image of the first group.