	US 11,743,669 B2
	Method and device for decoding a higher-order ambisonics (HOA) representation of an audio soundfield
Johannes Boehm, Göttingen (DE); and Florian Keiler, Hannover (DE)
Assigned to Dolby Laboratories Licensing Corporation, San Francisco, CA (US)
Filed by Dolby Laboratories Licensing Corporation, San Francisco, CA (US)
Filed on Sep. 13, 2022, as Appl. No. 17/943,965.
Application 17/943,965 is a continuation of application No. 17/189,067, filed on Mar. 1, 2021, granted, now 11,451,920.
Application 17/189,067 is a continuation of application No. 16/789,077, filed on Feb. 12, 2020, granted, now 10,939,220, issued on Mar. 2, 2021.
Application 16/789,077 is a continuation of application No. 16/417,515, filed on May 20, 2019, granted, now 10,595,145, issued on Mar. 17, 2020.
Application 16/417,515 is a continuation of application No. 16/114,937, filed on Aug. 28, 2018, granted, now 10,306,393, issued on May 28, 2019.
Application 16/114,937 is a continuation of application No. 15/920,849, filed on Mar. 14, 2018, granted, now 10,075,799, issued on Sep. 11, 2018.
Application 15/920,849 is a continuation of application No. 15/619,935, filed on Jun. 12, 2017, granted, now 9,961,470, issued on May 1, 2018.
Application 15/619,935 is a continuation of application No. 14/415,561, granted, now 9,712,938, issued on Jul. 18, 2017, previously published as PCT/EP2013/065034, filed on Jul. 16, 2013.
Claims priority of application No. 12305862 (EP), filed on Jul. 16, 2012.
Prior Publication US 2023/0080860 A1, Mar. 16, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. H04S 7/00 (2006.01); H04S 3/00 (2006.01)

CPC H04S 7/30 (2013.01) [H04S 3/008 (2013.01); H04S 2420/11 (2013.01)]

4 Claims

4. An apparatus for decoding a Higher-Order Ambisonics (HOA) representation of a sound or sound field for audio playback, comprising:

a decoder configured to decode coefficients of the HOA sound field representation, the decoder including:

a receiver configured to receive a smoothed decode matrix D that is based on a mix matrix G and a mode matrix Ψ, wherein the mix matrix G was determined based on L speakers and positions of a spherical modelling grid, wherein the mode matrix Ψ was determined based on the spherical modelling grid and a HOA order N, and

wherein the smoothed decode matrix D is determined based on smoothing a first decode matrix D with smoothing coefficients, wherein the first decode matrix D is determined based on D=V Ŝ U^H, wherein U,V are based on Unitary matrices,

wherein a compact singular value decomposition of a product of the mode matrix Ψ with a transposed mix matrix is determined based on U S V^H=ΨG^T, wherein S was determined based on a diagonal matrix with singular value elements, wherein Ŝ is a truncated compact singular value decomposition matrix that is either an identity matrix or a modified diagonal matrix, the modified diagonal matrix being determined based on the diagonal matrix with singular value elements by replacing a singular value element that is larger or equal than a threshold by ones, and replacing a singular value element that is smaller than the threshold by zeros; and

a renderer configured for rendering coefficients of the HOA representation from a time domain to a spatial domain based on the smoothed decode matrix D.