METHOD AND APPARATUS FOR ENCODING MULTI-CHANNEL HOA AUDIO SIGNALS FOR NOISE REDUCTION, AND METHOD AND APPARATUS FOR DECODING MULTI-CHANNEL HOA AUDIO SIGNALS FOR NOISE REDUCTION

摘要

A method for encoding multi-channel HOA audio signals for noise reduction comprises steps of decorrelating the channels using an inverse adaptive DSHT, the inverse adaptive DSHT comprising a rotation operation and an inverse DSHT, with the rotation operation rotating the spatial sampling grid of the iDSHT, perceptually encoding each of the decorrelated channels, encoding rotation information, the rotation information comprising parameters defining said rotation operation, and transmitting or storing the perceptually encoded audio channels and the encoded rotation information.

主权项

1. A method for encoding multi-channel Higher Order Ambisonics (HOA) audio signals for noise reduction, comprising steps of
decorrelating the channels using an inverse adaptive Discrete Spherical Harmonics Transform (DSHT), the inverse adaptive DSHT comprising a rotation operation and an inverse DSHT, with the rotation operation rotating the spatial sampling grid of the iDSHT, wherein the spherical sample grid is rotated such that the logarithm of the term∑l=1LSd∑j=1LSd∑WSdl,j-∑(σSd12,…,σSdLSd2)  is minimized, wherein∑WSdl,j  are the absolute values of the elements of ΣWSd with a row index l and a column index j, andσSdl2are the diagonal elements of ΣWSd, where ΣWSd=WSd WSdH and WSd is a matrix having a size of number of audio channels by number of block processing samples, and WSd is the result of the inverse adaptive DSHT;
perceptually encoding each of the decorrelated channels; encoding rotation information, wherein the rotation information is a spatial vector {circumflex over (ψ)}rot with three components defining said rotation operation; and transmitting or storing the perceptually encoded audio channels and the encoded rotation information.