公开(公告)号：US20190297443A1

公开(公告)日：2019-09-26

申请号：US16379091

申请日：2019-04-09

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Sven Kordon ,  Alexander Krueger

IPC: 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. 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：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：US10334382B2

公开(公告)日：2019-06-25

申请号：US15891606

申请日：2018-02-08

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Sven Kordon ,  Alexander Krueger ,  Oliver Wuebbolt

IPC: H04S3/00 ,  G10L19/008 ,  G10L19/24

Abstract: A method for compressing a HOA signal being an input HOA representation with input time frames (C(k)) of HOA coefficient sequences comprises spatial HOA encoding of the input time frames and subsequent perceptual encoding and source encoding. Each input time frame is decomposed (802) into a frame of predominant sound signals (XPS(k−1)) and a frame of an ambient HOA component ({tilde over (C)}AMB(k−1)). The ambient HOA component ({tilde over (C)}AMB(k−1)) comprises, in a layered mode, first HOA coefficient sequences of the input HOA representation (cn(k−1)) in lower positions and second HOA coefficient sequences (cAMB,n(k−1)) in remaining higher positions. The second HOA coefficient sequences are part of an HOA representation of a residual between the input HOA representation and the HOA representation of the predominant sound signals.

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：US10038965B2

公开(公告)日：2018-07-31

申请号：US15435175

申请日：2017-02-16

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Alexander Krueger ,  Sven Kordon ,  Johannes Boehm

IPC: H04R5/00 ,  H04S7/00 ,  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：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.