Apparatus, method and computer program for encoding, decoding, scene processing and other procedures related to DirAC based spatial audio coding using low-order, mid-order and high-order components generators

Patent metadata

Field	Value
Publication number	US-11937075-B2
Application number	US-202117332358-A
Country	US
Kind code	B2
Filing date	May 27, 2021
Priority date	Dec 7, 2018
Publication date	Mar 19, 2024
Grant date	Mar 19, 2024

Abstract

An apparatus for generating a sound field description using an input signal having a mono-signal or a multi-channel signal comprises: 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; 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 first truncation 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; and a high-order components generator for generating a high-order sound field description having a component above the first truncation order using a synthesis of at least one direct portion.

First claim

The invention claimed is:

1. 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 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,
wherein the low-order components generator is configured to generate K low-order sound field components, with K being 1 or greater than 1 and depending on the predetermined order and the predetermined mode, wherein the mid-order components generator is configured to generate (L+1) 2 −K mid-order sound field components, L being greater than K and depending on the high order, and wherein the high-order components generator is configured to generate (H+1) 2 −(L+1) 2 high-order sound field components, wherein H is an integer greater than L and wherein H represents a maximum order of the generated sound field description, or
wherein the mid-order components generator comprises: a reference signal generator for providing a reference signal for a sound field component of the mid-order sound field description and for modifying the reference signal using the directional data; a decorrelator for decorrelating the reference signal or a signal derived from the reference signal to acquire a decorrelated signal; and a mixer for mixing the modified reference signal and the decorrelated signal using the diffuseness data, or
wherein the low-order components generator is configured to perform an energy compensation to a directional component comprised in the input signal or derived from the input signal by copying, taking or performing a weighted combination, and wherein the low-order components generator comprises: an estimator for estimating a first energy- or amplitude-related measure for an omnidirectional component derived from the input signal and for estimating a second energy- or amplitude-related measure for a directional component derived from the input signal; and wherein the low-order components generator is configured to perform an energy compensation of the directional component using the first energy- or amplitude-related measure, the second energy- or amplitude-related measure, the direction data and the diffuseness data, or
wherein the low-order components generator is configured to perform an energy compensation to a directional component comprised in the input signal or derived from the input signal by copying, taking or performing a weighted combination, wherein the low-order components generator comprises an energy compensator for performing the energy compensation, the energy compensator comprising a compensation gain calculator for calculating a compensation gain using the diffuseness data, a maximum order of the sound field components of a first group and a maximum order of the sound field components of a second group, wherein the maximum order of the sound field components of the second group depends of the number of sound field components in the second group.

2. Apparatus of claim 1 , wherein the input signal analyzer is configured to extract the diffuseness data from metadata associated with the input signal or to extract the diffuseness data from the input signal by a signal analysis of the input signal comprising two or more channels or components.

3. 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 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,
wherein the apparatus further comprises a sound field combiner for combining low-order sound field components of the low-order sound field description, mid-order sound field components of the mid-order sound field description and high-order sound field components of the high-order sound field description to obtain a combined sound field having (H+1) 2 sound field components, wherein H is a maximum order of the generated sound field description, or
wherein the apparatus further comprises a directional gains calculator for calculating directional gains for mid-order sound field components of the mid-order sound field description and high-order sound field components of the high-order sound field description from the direction data and/or the diffuseness data and for feeding the directional gains for the mid-order sound field components to the mid-order components generator and for feeding the directional gains for the high-order sound field components to the high-order components generator, or
wherein the high-order components generator is configured to only synthesize a direct portion for a sound field component of the high-order sound field description using the direction data, and wherein the apparatus further comprises a directional gain calculator for the sound field component of the high-order sound field description configured for evaluating a spatial basis function for an order and a mode of the component of the high-order sound field description, wherein the high-order components generator is configured to derive the sound field component from a reference signal and the directional gain.

4. Apparatus of claim 3 , wherein the directional gains calculator is configured
to receive, for each time-frequency tile of a plurality of time-frequency tiles, the directional data and/or the diffuseness data, and
to evaluate a spatial basis function for a certain order and mode using the directional data to obtain the directional gain for the certain order and mode.

5. 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 ord

Assignees

• Fraunhofer Ges Forschung
• Fraunhofer Ges Zur Foerderung Der Angewand Forschung E V

Inventors

• Fuchs Guillaume
• Thiergart Oliver
• Korse Srikanth
• Döhla Stefan
• Multrus Markus
• Küch Fabian
• Bouthéon Alexandre
• Eichenseer Andrea
• Bayer Stefan

Classifications

• H04N19/593

  involving spatial prediction techniques · CPC title

• H04N19/176

  the region being a block, e.g. a macroblock · CPC title

• H04N19/119

  Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks · CPC title

• H04S2420/13

  Application of wave-field synthesis in stereophonic audio systems · CPC title

• H04S2420/11

  Application of ambisonics in stereophonic audio systems · CPC title