公开(公告)号：US20200382889A1

公开(公告)日：2020-12-03

申请号：US16903238

申请日：2020-06-16

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Florian Keiler ,  Johannes Boehm

IPC: H04S3/02 ,  H04S7/00

Abstract: Improved methods and/or apparatus for decoding an encoded audio signal in soundfield format for L loudspeakers. The method and/or apparatus can render an Ambisonics format audio signal to 2D loudspeaker setup(s) based on a rendering matrix. The rendering matrix has elements based on loudspeaker positions and wherein the rendering matrix is determined based on weighting at least an element of a first matrix with a weighting factor g=1/√{square root over (L)}. The first matrix is determined based on positions of the L loudspeakers and at least a virtual position of at least a virtual loudspeaker that is added to the positions of the L loudspeakers.

公开(公告)号：US10694308B2

公开(公告)日：2020-06-23

申请号：US16189732

申请日：2018-11-13

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Florian Keiler ,  Johannes Boehm

IPC: H04S3/02 ,  H04R5/02 ,  H04S5/02 ,  H04S7/00

Abstract: Improved methods and/or apparatus for decoding an encoded audio signal in soundfield format for L loudspeakers. The method and/or apparatus can render an Ambisonics format audio signal to 2D loudspeaker setup(s) based on a rendering matrix. The rendering matrix has elements based on loudspeaker positions and wherein the rendering matrix is determined based on weighting at least an element of a first matrix with a weighting factor g=1/√{square root over (L)}. The first matrix is determined based on positions of the L loudspeakers and at least a virtual position of at least a virtual loudspeaker that is added to the positions of the L loudspeakers.

公开(公告)号：US09813834B2

公开(公告)日：2017-11-07

申请号：US15030066

申请日：2014-10-20

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Florian Keiler ,  Johannes Boehm

IPC: H04S3/02 ,  G10L19/008 ,  H04S5/02 ,  H04S3/00 ,  H04S7/00

CPC classification number: H04S3/02 ,  H04S7/308 ,  H04S2400/11 ,  H04S2420/07 ,  H04S2420/11

Abstract: Sound scenes in 3D can be synthesized or captured as a natural sound field. For decoding, a decode matrix is required that is specific for a given loudspeaker setup and is generated using the known loudspeaker positions. However, some source directions are attenuated for 2D loudspeaker setups like e.g. 5.1 surround. An improved method for decoding an encoded audio signal in soundfield format for L loudspeakers at known positions comprises steps of adding (10) a position of at least one virtual loudspeaker to the positions of the L loudspeakers, generating (11) a 3D decode matrix (D′), wherein the positions (Formula I) of the L loudspeakers and the at least one virtual position (Formula II) are used, downmixing (12) the 3D decode matrix (D′), and decoding (14) the encoded audio signal (i14) using the downscaled 3D decode matrix (Formula III). As a result, a plurality of decoded loudspeaker signals (q14) is obtained.

公开(公告)号：US11451918B2

公开(公告)日：2022-09-20

申请号：US17231291

申请日：2021-04-15

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Florian Keiler ,  Johannes Boehm

IPC: H04S3/02 ,  H04R5/02 ,  H04S5/02 ,  H04S7/00

Abstract: Improved methods and/or apparatus for decoding an encoded audio signal in soundfield format for L loudspeakers. The method and/or apparatus can render an Ambisonics format audio signal to 2D loudspeaker setup(s) based on a rendering matrix. The rendering matrix has elements based on loudspeaker positions and wherein the rendering matrix is determined based on weighting at least an element of a first matrix with a weighting factor g = 1 L . The first matrix is determined based on positions of the L loudspeakers and at least a virtual position of at least a virtual loudspeaker that is added to the positions of the L loudspeakers.

公开(公告)号：US10522159B2

公开(公告)日：2019-12-31

申请号：US16514446

申请日：2019-07-17

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Johann-Markus Batke ,  Florian Keiler ,  Johannes Boehm

IPC: G10L19/008 ,  H04S7/00 ,  H04S3/02

Abstract: Soundfield signals such as e.g. Ambisonics carry a representation of a desired sound field. Methods and apparatus for improved decoding an audio soundfield representation for audio playback comprise receiving, by a processor configured to decode the audio soundfield representation, the audio soundfield representation, receiving, by the processor, a decode matrix for decoding the audio soundfield representation to determine a decoded audio signal. The decode matrix is based on an inverse of a mode matrix, and the coefficients of the mode matrix relate to information for a panning based on positions of loudspeakers over a unit sphere. The mode matrix is further based on an order N. The decoded audio signal is determined based on a multiplication of the decode matrix and the audio soundfield representation.

公开(公告)号：US10515645B2

公开(公告)日：2019-12-24

申请号：US16457501

申请日：2019-06-28

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Florian Keiler ,  Sven Kordon ,  Alexander Krueger

IPC: G10L19/008 ,  H04S3/00 ,  H04S3/02

Abstract: The present invention relates to methods and apparatus for encoding an HOA signal representation (c(t)) of a sound field having an order of N and a number O=(N+1)2 of coefficient sequences to a mezzanine HOA signal representation (wMEZZ(t)) is generated that consists of an arbitrary number I of virtual loudspeaker signals wMEZZ,1(t), wMEZZ,2(t), . . . , wMEZZ,I(t). The present invention further relates to methods and apparatus for decoding a reconstructed HOA signal representation from the mezzanine HOA signal representation.

公开(公告)号：US10341802B2

公开(公告)日：2019-07-02

申请号：US15768695

申请日：2016-11-11

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Alexander Krueger ,  Johannes Boehm ,  Sven Kordon ,  Xiaoming Chen ,  Stefan Abeling ,  Florian Keiler ,  Holger Kropp

IPC: H04S7/00 ,  H04S3/00

Abstract: Currently there is no simple and satisfying way to create 3D audio from existing 2D content. The conversion from 2D to 3D sound should spatially redistribute the sound from existing channels. From a multi-channel 2D audio input signal (x(k)(t)) a 3D sound representation is generated which includes an HOA representation Formula (I) and channel object signals Formula (II) scaled from channels of the 2D audio input signal. Additional signals Formula (III) placed in the 3D space are generated by scaling (21, 222; 41, 422; Formula (IV)) channels from the 2D audio input signal and by decorrelating (24, 25; 44, 45, 451; Formula (V)) a scaled version of a mix of channels from the 2D audio input signal, whereby spatial positions for the additional signals are predetermined. The additional signals Formula (III) are converted (27; 47) to a HOA representation Formula (I).

公开(公告)号：US10262663B2

公开(公告)日：2019-04-16

申请号：US15509596

申请日：2015-09-25

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Alexander Krueger ,  Sven Kordon ,  Florian Keiler

IPC: H04S3/02 ,  G10L19/008

Abstract: The invention is suited for improving a low bit rate compressed and decompressed Higher Order Ambisonics HOA signal representation of a sound field, wherein the decompression provides a spatially sparse decoded HOA representation and a set of indices of coefficient sequences of this representation. From reconstructed signals of the original HOA representation a number of modified phase spectra signals are created using de-correlation filters, which modified phase spectra signals are uncorrelated with the signals of said original representation. The modified phase spectra signals are mixed with each other using predetermined mixing parameters, in order to provide a replicated ambient HOA component. Finally the spatially sparse decoded HOA representation is enhanced with the replicated time domain HOA representation.

公开(公告)号：US10134405B2

公开(公告)日：2018-11-20

申请号：US16019233

申请日：2018-06-26

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Johann-Markus Batke ,  Florian Keiler ,  Johannes Boehm

IPC: G10L19/008 ,  H04S3/02 ,  H04S7/00

Abstract: Soundfield signals such as e.g. Ambisonics carry a representation of a desired sound field. The Ambisonics format is based on spherical harmonic decomposition of the soundfield, and Higher Order Ambisonics (HOA) uses spherical harmonics of at least 2nd order. However, commonly used loudspeaker setups are irregular and lead to problems in decoder design. A method for improved decoding an audio soundfield representation for audio playback comprises calculating a panning function (W) using a geometrical method based on the positions of a plurality of loudspeakers and a plurality of source directions, calculating a mode matrix (Ξ) from the loudspeaker positions, calculating a pseudo-inverse mode matrix (Ξ+) and decoding the audio soundfield representation. The decoding is based on a decode matrix (D) that is obtained from the panning function (W) and the pseudo-inverse mode matrix (Ξ+).

公开(公告)号：US12108236B2

公开(公告)日：2024-10-01

申请号：US18359198

申请日：2023-07-26

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Johannes Boehm ,  Florian Keiler

IPC: H04S7/00 ,  H04S3/00

CPC classification number: H04S7/30 ,  H04S3/008 ,  H04S2420/11

Abstract: The invention discloses rendering sound field signals, such as Higher-Order Ambisonics (HOA), for arbitrary loudspeaker setups, where the rendering results in highly improved localization properties and is energy preserving. This is obtained by rendering an audio sound field representation for arbitrary spatial loudspeaker setups and/or by a a decoder that decodes based on a decode matrix (D). The decode matrix (D) is based on smoothing and scaling of a first decode matrix {circumflex over (D)} with smoothing coefficients. The first decode matrix {circumflex over (D)} is based on a mix matrix G and a mode matrix {tilde over (ψ)}, where the mix matrix G was determined based on L speakers and positions of a spherical modelling grid related to a HOA order N, and the mode matrix {tilde over (ψ)} was determined based on the spherical modelling grid and the HOA order N.