公开(公告)号：US10021508B2

公开(公告)日：2018-07-10

申请号：US15357810

申请日：2016-11-21

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Sven Kordon ,  Johann-Markus Batke ,  Alexander Krueger ,  Mark R. P. Thomas

IPC: H04R3/00 ,  H04S7/00

CPC classification number: H04S7/307 ,  H04R1/326 ,  H04R1/406 ,  H04R3/005 ,  H04R5/027 ,  H04R29/005 ,  H04R2201/401 ,  H04S3/002 ,  H04S2400/15 ,  H04S2420/11

Abstract: Spherical microphone arrays capture a three-dimensional sound field (P(Ωc, t)) for generating an Ambisonics representation (Anm(t)), where the pressure distribution on the surface of the sphere is sampled by the capsules of the array. The impact of the microphones on the captured sound field is removed using the inverse microphone transfer function. The equalization of the transfer function of the microphone array is a big problem because the reciprocal of the transfer function causes high gains for small values in the transfer function and these small values are affected by transducer noise. The invention minimizes that noise by using a Wiener filter processing in the frequency domain, which processing is automatically controlled per wave number by the signal-to-noise ratio of the microphone array.

公开(公告)号：US09990934B2

公开(公告)日：2018-06-05

申请号：US15110354

申请日：2014-12-19

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Alexander Krueger ,  Sven Kordon ,  Oliver Wuebbolt

IPC: H04R5/00 ,  G10L19/20 ,  G10L19/008 ,  H04S3/00

CPC classification number: G10L19/20 ,  G10L19/008 ,  H04S3/008 ,  H04S2420/11

Abstract: Higher Order Ambisonics represents three-dimensional sound independent of a specific loudspeaker set-up. However, transmission of an HOA representation results in a very high bit rate. Therefore compression with a fixed number of channels is used, in which directional and ambient signal components are processed differently. For coding, portions of the original HOA representation are predicted from the directional signal components. This prediction provides side information which is required for a corresponding decoding. By using some additional specific purpose bits, a known side information coding processing is improved in that the required number of bits for coding that side information is reduced on average.

公开(公告)号：US09794714B2

公开(公告)日：2017-10-17

申请号：US15320467

申请日：2015-07-02

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Alexander Krueger ,  Sven Kordon

IPC: H04R5/00 ,  H04S3/02 ,  H04S3/00 ,  G10L19/02 ,  G10L19/008

CPC classification number: H04S3/02 ,  G10L19/008 ,  G10L19/0208 ,  H04S3/008 ,  H04S2420/07 ,  H04S2420/11

Abstract: Encoding of Higher Order Ambisonics (HOA) signals commonly results in high data rates. A method for low bit-rate encoding frames of an input HOA signal having coefficient sequences comprises computing (s110) a truncated HOA representation (CT(k)), determining (s111) active coefficient sequences (IC,ACTT(k)), estimating (s16) candidate directions (MDIR(k)), dividing (s15) the input HOA signal into a plurality of frequency subbands (f1, . . . , fF), estimating (s161) for each of the frequency subbands a subset of candidate directions (MDIR(k)) as active directions (MDIR(k,f1), . . . , MDIR(k,fF)) and for each active direction a trajectory, computing (s17) for each frequency subband directional subband signals from the coefficient sequences of the frequency subband according to the active directions, calculating (s18) for each frequency subband a prediction matrix (A(k,f1), . . . , A(k,fF)) that can be used for predicting the directional subband signals from the coefficient sequences of the frequency subband using the respective active coefficient sequences (K)), and encoding (s19) the candidate directions, active directions, prediction matrices and truncated HOA representation.

公开(公告)号：US09774975B2

公开(公告)日：2017-09-26

申请号：US15320461

申请日：2015-07-02

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Alexander Krueger ,  Sven Kordon

IPC: H04R5/00 ,  H04S3/02 ,  H04S3/00 ,  G10L19/008 ,  G10L19/02

CPC classification number: H04S3/02 ,  G10L19/008 ,  G10L19/0204 ,  H04S3/008 ,  H04S2420/07 ,  H04S2420/11

Abstract: Encoding of Higher Order Ambisonics (HOA) signals commonly results in high data rates. A method for low bit-rate encoding frames of an input HOA signal having coefficient sequences comprises computing (s110) a truncated HOA representation (CT(k)), determining (s111) active coefficient sequences (Ic,Act(k)), estimating (s16) candidate directions (MDIR(k)), dividing (s15) the input HOA signal into a plurality of frequency subbands (f1, . . . , fF), estimating (s161) for each of the frequency subbands a subset of candidate directions (MDIR(k)) as active directions (MDIR(k,f1), . . . , MDIR(k,fF)) and for each active direction a trajectory, computing (s17) for each frequency subband directional subband signals from the coefficient sequences of the frequency subband according to the active directions, calculating (s18) for each frequency subband a prediction matrix (A(k,f1), . . . , A(k,fF)) that can be used for predicting the directional subband signals from the coefficient sequences of the frequency subband using the respective active coefficient sequences (Ic,ACT(k)), and encoding (s19) the candidate directions, active directions, prediction matrices and truncated HOA representation.

公开(公告)号：US09736607B2

公开(公告)日：2017-08-15

申请号：US14787978

申请日：2014-04-24

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Alexander Krueger ,  Sven Kordon

IPC: H04R5/00 ,  H04S3/00 ,  G10L19/008

CPC classification number: H04S3/008 ,  G10L19/008 ,  H04S2420/03 ,  H04S2420/11 ,  H04S2420/13

Abstract: Higher Order Ambisonics represents three-dimensional sound independent of a specific loudspeaker set-up. However, transmission of an HOA representation results in a very high bit rate. Therefore compression with a fixed number of channels is used, in which directional and ambient signal components are processed differently. The ambient HOA component is represented by a minimum number of HOA coefficient sequences. The remaining channels contain either directional signals or additional coefficient sequences of the ambient HOA component, depending on what will result in optimum perceptual quality. This processing can change on a frame-by-frame basis.

公开(公告)号：US09646618B2

公开(公告)日：2017-05-09

申请号：US14651313

申请日：2013-12-04

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Alexander Krueger ,  Sven Kordon ,  Johannes Boehm

IPC: H04S3/00 ,  G10L19/008

CPC classification number: H04S7/302 ,  G10L19/008 ,  H04S3/008 ,  H04S2400/01 ,  H04S2420/11

Abstract: The invention improves HOA sound field representation compression. The HOA representation is analyzed for the presence of dominant sound sources and their directions are estimated. Then the HOA representation is decomposed into a number of dominant directional signals and a residual component. This residual component is transformed into the discrete spatial domain in order to obtain general plane wave functions at uniform sampling directions, which are predicted from the dominant directional signals. Finally, the prediction error is transformed back to the HOA domain and represents the residual ambient HOA component for which an order reduction is performed, followed by perceptual encoding of the dominant directional signals and the residual component.

公开(公告)号：US20160337775A1

公开(公告)日：2016-11-17

申请号：US15221354

申请日：2016-07-27

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Alexander Krüger ,  Sven Kordon ,  Johannes Boehm ,  Johann-Markus Batke

IPC: H04S3/00 ,  G10L19/20 ,  G10L19/008

CPC classification number: H04S3/008 ,  G10L19/008 ,  G10L19/20 ,  H04H20/89 ,  H04S3/02 ,  H04S2420/11

Abstract: A method and apparatus for decompressing a Higher Order Ambisonics (HOA) signal representation is disclosed. The apparatus includes an input interface that receives an encoded directional signal and an encoded ambient signal and an audio decoder that perceptually decodes the encoded directional signal and encoded ambient signal to produce a decoded directional signal and a decoded ambient signal, respectively. The apparatus further includes an extractor for obtaining side information related to the directional signal and an inverse transformer for converting the decoded ambient signal from a spatial domain to an HOA domain representation of the ambient signal. The apparatus also includes a synthesizer for recomposing a Higher Order Ambisonics (HOA) signal from the HOA domain representation of the ambient signal and the decoded directional signal. The side information includes a direction of the directional signal selected from a set of uniformly spaced directions.

Abstract translation: 公开了一种用于解压缩高阶Ambisonics（HOA）信号表示的方法和装置。 该装置包括输入接口，其接收编码的定向信号和经编码的环境信号，以及音频解码器，其分别感知地解码编码的方向信号和编码的环境信号以产生解码的定向信号和解码的环境信号。 该装置还包括一个提取器，用于获取与定向信号有关的侧面信息;以及一个逆变换器，用于将解码的环境信号从空间域转换为环境信号的HOA域表示。 该装置还包括合成器，用于从环境信号的HOA域表示和解码的定向信号重构高阶环境（HOA）信号。 侧信息包括从一组均匀间隔的方向选择的方向信号的方向。

公开(公告)号：US09460728B2

公开(公告)日：2016-10-04

申请号：US14415571

申请日：2013-07-16

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Johannes Boehm ,  Sven Kordon ,  Alexander Krueger ,  Peter Jax

IPC: G10L19/012 ,  G10L19/008 ,  H04S3/02

CPC classification number: G10L19/012 ,  G10L19/008 ,  G10L19/0212 ,  G10L19/038 ,  H04S3/02 ,  H04S2420/11

Abstract: 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.

Abstract translation: 用于编码用于降噪的多声道HOA音频信号的方法包括以下步骤：使用逆自适应DSHT去除相关信道的步骤，逆自适应DSHT包括旋转操作和反向DSHT，旋转操作旋转iDSHT的空间采样网格 感知地编码每个解相关通道，编码旋转信息，旋转信息包括定义所述旋转操作的参数，以及发送或存储感知编码的音频通道和编码旋转信息。

公开(公告)号：US12245013B2

公开(公告)日：2025-03-04

申请号：US18517301

申请日：2023-11-22

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Sven Kordon ,  Alexander Krueger

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

Abstract: There are two representations for Higher Order Ambisonics denoted HOA: spatial domain and coefficient domain. The invention generates from a coefficient domain representation a mixed spatial/coefficient domain representation, wherein the number of said HOA signals can be variable. An aspect of the invention further relates to methods and apparatus decoding multiplexed and perceptually encoded HOA signals, including transforming a vector of PCM encoded spatial domain signals of the HOA representation to a corresponding vector of coefficient domain signals by multiplying the vector of PCM encoded spatial domain signals with a transform matrix and de-normalizing the vector of PCM encoded and normalized coefficient domain signals, wherein said de-normalizing comprises. The methods may include combining a vector of coefficient domain signals and the vector of de-normalized coefficient domain signals to determine a combined vector of HOA coefficient domain signals that can have a variable number of HOA coefficients.

公开(公告)号：US20220115027A1

公开(公告)日：2022-04-14

申请号：US17558550

申请日：2021-12-21

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Sven Kordon ,  Alexander Krueger ,  Oliver Wuebbolt

IPC: G10L19/20 ,  H04S3/00 ,  G10L19/008

Abstract: Higher Order Ambisonics represents three-dimensional sound independent of a specific loudspeaker set-up. However, transmission of an HOA representation results in a very high bit rate. Therefore compression with a fixed number of channels is used, in which directional and ambient signal components are processed differently. For coding, portions of the original HOA representation are predicted from the directional signal components. This prediction provides side information which is required for a corresponding decoding. By using some additional specific purpose bits, a known side information coding processing is improved in that the required number of bits for coding that side information is reduced on average.