Apparatus and method for generating a plurality of audio channels

Patent metadata

Field	Value
Publication number	US-9729995-B2
Application number	US-201615202443-A
Country	US
Kind code	B2
Filing date	Jul 5, 2016
Priority date	Jan 7, 2014
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

An apparatus for generating a plurality of audio channels for a first speaker setup is characterized by an imaginary speaker determiner, an energy distribution calculator, a processor and a renderer. The imaginary speaker determiner is configured to determine a position of an imaginary speaker not contained in the first speaker setup to obtain a second speaker setup containing the imaginary speaker. The energy distribution calculator is configured to calculate an energy distribution from the imaginary speaker to the other speakers in the second speaker setup. The processor is configured to repeat the energy distribution to obtain a downmix information for a downmix from the second speaker setup to the first speaker setup. The renderer is configured to generate the plurality of audio channels using the downmix information.

First claim

The invention claimed is:

1. An apparatus for generating a plurality of audio channels for a first speaker setup, wherein:
an imaginary speaker determiner for determining a position of an imaginary speaker not comprised in the first speaker setup to acquire a second speaker setup comprising the imaginary speaker and at least partially speakers of the first speaker setup;
an energy distribution calculator for calculating an energy distribution from the imaginary speaker to other speakers in the second speaker setup, wherein the energy distribution represents an amount or a share of an energy of the imaginary speaker being distributed to the other speakers in the second speaker setup;
a processor for computing a power of the energy distribution to acquire a downmix information for a downmix from the second speaker setup to the first speaker setup;
wherein the processor is configured to generate an energy distribution matrix based on the energy distribution, wherein the energy distribution matrix comprises elements representing the energy distribution of the imaginary speaker to another speaker of the second speaker setup, wherein the power of the energy distribution leads the elements representing the energy distribution of the imaginary speaker to the other speaker of the second speaker setup to decrease; and
a renderer for generating the plurality of audio channels using the downmix information.

2. The apparatus according to claim 1 , wherein the processor is further configured to calculate a power of the energy distribution matrix, wherein an exponent of the power is a predefined value, and wherein the processor is configured to acquire the downmix information based on the power of the energy distribution matrix.

3. The apparatus according to claim 1 , wherein the processor is further configured to iteratively calculate a power of the energy distribution matrix, wherein a number of iteration steps is based on a value of the power of the energy distribution matrix.

4. The apparatus according to claim 1 , wherein the energy distribution calculator comprises a neighborhood estimator for determining a neighborhood relation of the imaginary speaker in the second speaker setup to at least one speaker of the second speaker setup that is a neighbor of the imaginary speaker, and wherein the energy distribution calculator is configured to calculate the energy distribution of the imaginary speaker to the at least one neighbor of the imaginary speaker.

5. The apparatus according to claim 4 , wherein the neighborhood estimator is configured to determine a neighborhood relation of the imaginary speaker in the second speaker setup to at least two speakers in the second speaker setup that are neighbors of the imaginary speaker and wherein the energy distribution calculator is configured to calculate the energy distribution such that the energy distribution among the at least two speakers that are neighbors of the imaginary speaker is equal within a predefined tolerance.

6. The apparatus according to claim 5 , wherein the neighborhood estimator is configured to determine a neighborhood relation of the imaginary speaker in the second speaker setup to at least two speakers that are neighbors of the imaginary speaker and wherein at least one of the at least two speakers that are neighbors of the imaginary speaker is a further imaginary speaker.

7. The apparatus according to claim 1 , wherein the imaginary speaker is arranged at one side of a geometric plane comprising speakers of the first speaker setup within a predefined tolerance and a predefined listener position.

8. The apparatus according to claim 1 , wherein the imaginary speaker is arranged along a second side of a geometric plane comprising a predefined listener position opposing a first side of the geometric plane, wherein a speaker of the first speaker setup is arranged at the first side of the geometric plane.

9. The apparatus according to claim 1 , wherein the apparatus is comprised by a format conversion unit, wherein the format conversion unit is configured to output the plurality of audio channels based on input channels comprising a plurality of data channels and wherein a number of data channels is higher than a number of the plurality of audio channels.

10. The apparatus according to claim 1 , wherein the apparatus comprises a panner for generating panning coefficients for the second speaker setup, and wherein the render is configured to generate the plurality of audio channels based on the downmix information and the panning coefficients.

11. The apparatus according to claim 10 , wherein the apparatus is comprised by an object renderer, wherein the object renderer is configured to output the plurality of audio channels based on position information of audio objects and wherein a number of panning coefficients is higher than a number of the plurality of audio channels such that the audio object is rendered to the first speaker setup.

12. The apparatus according to claim 1 , wherein the imaginary speaker determiner is configured to calculate a convex hull based on a position of speakers of the first speaker setup and to determine the position of the imaginary speaker according to a QuickHull algorithm, wherein the position of the imaginary speaker and the position of speakers of the first speaker setup is arranged at the convex hull within a predefined threshold.

13. The apparatus according to claim 12 , wherein the apparatus is configured to provide a validity information of the first speaker setup indicating that a position of every speaker in the first speaker setup is arranged at the convex hull within a predefined threshold or indicating that a position of at least one speaker in the first speaker setup is arranged outside the convex hull within a predefined threshold.

14. An audio system, comprising an apparatus according to claim 1 ; and
a plurality of speakers according to the plurality of audio channels;
wherein the plurality of speakers is configured to receive the plurality of audio channels and to provide a plurality of acoustic signals based on the plurality of audio channels.

15. A method for generating a plurality of audio channels for a first speaker setup, comprising:
determining a position of an imaginary speaker not comprised in the first speaker setup and acquiring a second speaker setup comprising the imaginary speaker and at least partially speakers of the first speaker setup;
calculating an energy distribution from the imaginary speaker to the other speakers in the second speaker setup, wherein the energy distribution represents an amount or a share of an energy of the imaginary speaker being distributed to the other speakers in the second speaker setup;
computing a power of the energy distribution and acquire a downmix information for a downmix from the second speaker setup to the first speaker setup, wherein the power of the energy distribution leads elements of the acquired energy distribution to decrease;
wherein computing of the power of the energy distribution comprises generating an energy distribution matrix based on the energy distribution, wherein the energy distribution matrix comprises elements representing the energy distribution of the imaginary speaker to another speaker of the second speaker setup, wherein the power of the energy distribution leads the elements representing the energy distribution of the imaginary speaker to the other speaker of the second speaker setup to decrease; and
generating the plurality of audio channels using the downmix information.

16. A non-transitory digital storage medium having stor

Assignees

• Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E V

Inventors

• Borss Christian
• Ertel Christian
• Hilpert Johannes
• Kuntz Achim
• Fischer Michael
• Schuh Florian
• Grill Bernhard

Classifications

• H04S2400/11

  Positioning of individual sound objects, e.g. moving airplane, within a sound field (H04S2420/13 takes precedence) · CPC title

• H04S7/30

  Control circuits for electronic adaptation of the sound field · CPC title

• G10L19/20

  using sound class specific coding, hybrid encoders or object based coding · CPC title

• G10L19/008 Primary

  Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing · CPC title

• H04S2400/03

  Aspects of down-mixing multi-channel audio to configurations with lower numbers of playback channels, e.g. 7.1 -> 5.1 (H04S2400/01 takes precedence) · CPC title