Granted Patent B2

US 12,574,700 · App. 18/801,923 · Granted Mar 10, 2026

Inventors: Guillaume Fuchs (Erlangen, DE); Oliver Thiergart (Erlangen, DE); Srikanth Korse (Erlangen, DE); Stefan Döhla (Erlangen, DE); Markus Multrus (Erlangen, DE); Fabian Küch (Erlangen, DE); Alexandre Bouthéon (Erlangen, DE); Andrea Eichenseer (Erlangen, DE); Stefan Bayer (Erlangen, DE)

Assignee: FRAUNHOFER-GESELLSCHAFT ZUR FÖRDERUNG DER ANGEWANDTEN FORSCHUNG E.V.

H04S7/307G10L19/02G10L19/0212H04N19/119H04N19/176H04N19/593H04S2400/01H04S2420/11H04S2420/13

Abstract

Claims (36)

1 . An apparatus for generating a sound field description using an input signal comprising a mono-signal or a multi-channel signal, the apparatus comprising:

an input signal analyzer for analyzing the input signal to derive direction data and diffuseness data;

a low-order components generator for generating a low-order sound field description from the input signal up to a predetermined order and mode, wherein the low-order components generator is configured to derive the low-order sound field description by copying or taking the input signal or performing a weighted combination of the channels of the input signal;

a mid-order components generator for generating a mid-order sound field description above the predetermined order or at the predetermined order and above the predetermined mode and below or at a high order using a synthesis of at least one direct portion and of at least one diffuse portion using the direction data and the diffuseness data so that the mid-order sound field description comprises a direct contribution and a diffuse contribution; and

a high-order components generator for generating a high-order sound field description comprising a sound field component above the high order using a synthesis of at least one direct portion, wherein the high-order sound field description comprises a direct contribution only.

2 . The apparatus of claim 1 , wherein the input signal analyzer is configured to extract the diffuseness data from metadata associated with the input signal.

3 . The apparatus of claim 1 , wherein the input signal analyzer is configured to extract the diffuseness data from the input signal by a signal analysis of the input signal comprising two or more channels or components.

4 . The apparatus of claim 1 , wherein the input signal comprises the mono signal, and wherein the low-order components generator is configured to generate a zero order Ambisonics signal by taking the mono signal.

5 . The apparatus of claim 1 , wherein the input signal comprises the mono signal, and wherein the low-order components generator is configured to generate a zero order Ambisonics signal by copying the mono signal.

6 . The apparatus of claim 1 , wherein the input signal comprises a first order Ambisonics signal with three or four channels, and wherein the low-order components generator is configured to generate a first order Ambisonics signal by taking the three or four channels of the input signal.

7 . The apparatus of claim 1 , wherein the input signal comprises a first order Ambisonics signal with three or four channels, and wherein the low-order components generator is configured to generate a first order Ambisonics signal by copying the three or four channels of the input signal.

8 . The apparatus of claim 1 , wherein the high-order components generator is configured to only synthesize a direct portion for the sound field component of the high-order sound field description using the direction data.

9 . The apparatus of claim 1 , wherein the mid-order components generator is configured to perform an energy compensation to the at least one diffuse portion of the mid-order sound field description to compensate for an energy loss due to the high-order sound field description only comprising the direct component, and wherein the energy compensation depends on the diffuseness data and at least one of a number of sound field components generated by the high-order components generator, a number of diffuse components generated by the low-order components generator and/or the mid-order components generator, a maximum order of sound field components generated by the low-order components generator and/or the mid-order components generator and a maximum order of sound field components generated by the high-order components generator.

10 . The apparatus of claim 1 , wherein the mid-order components generator is configured to perform an energy compensation to a sound field component of the mid-order sound field description to compensate for an energy loss due to the high-order sound field description only comprising the direct component, and

wherein the energy compensation depends on the diffuseness data and at least one of a number of sound field components generated by the high-order components generator, a number of diffuse components generated by the low-order components generator and/or the mid-order components generator, a maximum order of sound field components generated by the low-order components generator and/or the mid-order components generator and a maximum order of sound field components generated by the high-order components generator.

11 . The apparatus of claim 1 , wherein the low-order components generator is configured to perform an energy compensation to a directional component comprised in the input signal.

12 . The apparatus of claim 1 , wherein the low-order components generator is configured to perform an energy compensation to a directional component derived from the input signal by copying.

13 . The apparatus of claim 1 , wherein the low-order components generator is configured to perform an energy compensation to a directional component derived from the input signal by taking.

14 . The apparatus of claim 1 , wherein the low-order components generator is configured to perform an energy compensation to a directional component derived from the input signal by performing a weighted combination.

15 . The apparatus of claim 1 , wherein a first group of sound field components and a second group of sound field components are orthogonal to each other.

16 . The apparatus of claim 1 , wherein the sound field components are at least one of coefficients of orthogonal basis functions, coefficients of spatial basis functions, and coefficients of spherical or circular harmonics.

17 . The apparatus of claim 1 , wherein the sound field components are Ambisonics coefficients.

18 . The apparatus of claim 1 further comprising:

an analysis filter bank for generating the one or more sound field components of a first group and a second group for a plurality of different time-frequency tiles,

wherein the input signal analyzer is configured to acquire a direction data item and a diffuseness data item for each time-frequency tile, and

wherein the low-order components generator, the mid-order components generator, or the high-order components generator is configured to operate separately for each time-frequency tile.

19 . A method for generating a sound field description using an input signal comprising a mono-signal or a multi-channel signal, comprising:

analyzing the input signal to derive direction data and diffuseness data;

generating a low-order sound field description from the input signal up to a predetermined order and mode, wherein the generating the low-order sound field description comprises deriving the low-order sound field description by copying the input signal or performing a weighted combination of the channels of the input signal;

generating a mid-order sound field description above the predetermined order or at the predetermined order and above the predetermined mode and below a high order using a synthesis of at least one direct portion and of at least one diffuse portion using the direction data and the diffuseness data so that the mid-order sound field description comprises a direct contribution and a diffuse contribution; and

generating a high-order sound field description comprising a component at or above the high order using a synthesis of at least one direct portion without any diffuse component synthesis so that the high-order sound field description comprises a direct contribution only.

20 . A non-transitory digital storage medium having a computer program stored thereon to perform, when said computer program is run by a computer, the method for generating a sound field description using an input signal comprising a mono-signal or a multi-channel signal, the method comprising:

analyzing the input signal to derive direction data and diffuseness data;

generating a low-order sound field description from the input signal up to a predetermined order and mode, wherein the generating the low-order sound field description comprises deriving the low-order sound field description by copying the input signal or performing a weighted combination of the channels of the input signal;

generating a mid-order sound field description above the predetermined order or at the predetermined order and above the predetermined mode and below a high order using a synthesis of at least one direct portion and of at least one diffuse portion using the direction data and the diffuseness data so that the mid-order sound field description comprises a direct contribution and a diffuse contribution; and

generating a high-order sound field description comprising a component at or above the high order using a synthesis of at least one direct portion without any diffuse component synthesis so that the high-order sound field description comprises a direct contribution only.

Assignments (1)

Continuity (5)

References Cited (130)