Method for processing an audio signal, signal processing unit, binaural renderer, audio encoder and audio decoder

Patent metadata

Field	Value
Publication number	US-10848900-B2
Application number	US-201815922138-A
Country	US
Kind code	B2
Filing date	Mar 15, 2018
Priority date	Jul 22, 2013
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

A method for processing an audio signal in accordance with a room impulse response is described. The audio signal is processed with an early part of the room impulse response separate from a late reverberation of the room impulse response, wherein the processing of the late reverberation has generating a scaled reverberated signal, the scaling being dependent on the audio signal. The processed early part of the audio signal and the scaled reverberated signal are combined.

First claim

The invention claimed is:

1. A method for processing an audio signal in accordance with a room impulse response, the method comprising:
applying the audio signal as an input signal to an early part processor and to a late reverberation processor;
processing, by the early part processor, the audio signal with an early part of the room impulse response to obtain a processed audio signal;
receiving, by the late reverberation processor, predefined reverberator parameters and processing the audio signal using the predefined reverberator parameters in accordance with a late reverberation of the room impulse response to obtain a reverberated signal and scaling the reverberated signal to obtain a scaled reverberated signal; and
combining the processed audio signal and the scaled reverberated signal,
wherein scaling the reverberated signal by the late reverberation processor comprises
setting a gain factor according to a predefined correlation measure of the audio signal, the predefined correlation measure having a fixed value determined empirically on the basis of an analysis of a plurality of audio signals, and applying the gain factor to the reverberated signal, or
obtaining a gain factor using a correlation analysis of the audio signal, and applying the gain factor to the reverberated signal.

2. The method of claim 1 , wherein the scaling is dependent on a condition of one or more input channels of the audio signal, wherein the condition of the one or more input channels of the audio signal comprises one or more of the number of input channels, the number of active input channels, and an activity in the one or more input channels.

3. The method of claim 2 , wherein the gain factor is determined based on the condition of the one or more input channels of the audio signal.

4. The method of claim 3 , wherein the gain factor is determined as follows:
g=c u +ρ·( c c −c u )

where
ρ=predefined or calculated correlation measure for the audio signal,
c u , c c =factors indicative of the condition of one or more input channels of the audio signal, with c u referring to totally uncorrelated channels, and c c relating to totally correlated channels,
wherein c u and c c are determined as follows:

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where
K in =number of active input channels of the audio signal.

5. The method of claim 1 , wherein the correlation analysis of the audio signal comprises determining for an audio frame of the audio signal a combined correlation measure, and wherein the combined correlation measure is calculated by combining correlation coefficients for a plurality of channel combinations of one audio frame, each audio frame comprising one or more time slots.

6. The method of claim 5 , wherein combining the correlation coefficients comprises averaging a plurality of correlation coefficients of the audio frame.

7. The method of claim 5 , wherein determining the combined correlation measure comprises:
(i) calculating an overall mean value for every channel of the one audio frame,
(ii) calculating a zero-mean audio frame by subtracting the mean values from the corresponding channels,
(iii) calculating for a plurality of channel combination the correlation coefficient, and
(iv) calculating the combined correlation measure as the mean of a plurality of correlation coefficients.

8. The method of claim 5 , wherein the correlation coefficient for a channel combination is calculated as follows:

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Assignees

• Fraunhofer Ges Forschung

Inventors

• NEUKAM Simone
• Plogsties Jan

Classifications

• 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

• H04S7/00 Primary

  Indicating arrangements; Control arrangements, e.g. balance control · CPC title

• G10K15/12

  using electronic time-delay networks · CPC title

• H03M7/30

  Compression (speech analysis-synthesis for redundancy reduction G10L19/00; for image communication H04N); Expansion; Suppression of unnecessary data, e.g. redundancy reduction · CPC title