Method and apparatus for higher order ambisonics encoding and decoding using singular value decomposition

US9736608B2 · kind B2 · utility

Assignee

• Dolby International AB · IE

Inventors

• Holger Kropp · Großburgwedel, DE
• Stefan Abeling · Winsen (Aller), DE

Key dates

• Filing date: Nov 18, 2014
• Grant date: Aug 15, 2017
• Expiry date: Nov 18, 2034

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04S2420/11
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

The encoding and decoding of HOA signals using Singular Value Decomposition includes forming (11) based on sound source direction values and an Ambisonics order corresponding ket vectors (|Y(Ω5))) of spherical harmonics and an encoder mode matrix (Ξ0χs). From the audio input signal (|χ(Ωs))) a singular threshold value (σε) determined. On the encoder mode matrix a Singular Value Decomposition (13) is carried out in order to get related singular values which are compared with the threshold value, leading to a final encoder mode matrix rank (rfine). Based on direction values (Ωl) of loudspeakers and a decoder Ambisonics order (Nl ), corresponding ket vectors (IY(Ωl )) and a decoder mode matrix (Ψ0χL) are formed (18). On the decoder mode matrix a Singular Value Decomposition (19) is carried out, providing a final decoder mode matrix rank (r find). From the final encoder and decoder mode matrix ranks a final mode matrix rank is determined, and from this final mode matrix rank and the encoder side Singular Value Decomposition an adjoint pseudo inverse (Ξ+)† of the encoder mode matrix (Ξ0χs) and an Ambisonics ket vector (Ia′s) are calculated. The number of components of the Ambisonics ket…