Audio signal processing method and device

• US 9,860,668 B2
• Filed: 04/02/2015
• Issued: 01/02/2018
• Est. Priority Date: 04/02/2014
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute, WILUS Inc.
• Original Assignee: Electronics and Telecommunications Research Institute, WILUS Inc.
• Inventors: Oh, Hyun Oh, Lee, Taegyu, Seo, Jeongil
• Primary Examiner(s): Edun, Muhammad N
• Application Number:
  US15/300,277
• Publication Number:
  US 20170188175A1
• Time in Patent Office: 1,006 Days
• CPC Class Codes: G10L 19/008 Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing
• CPC Class Codes: G10L 19/167 Audio streaming, i.e. formatting and decoding of an encoded audio signal representation into a data stream for transmission or storage purposes
• CPC Class Codes: H04R 2430/03 Synergistic effects of band splitting and sub-band processing
• CPC Class Codes: H04R 2499/11 Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's
• CPC Class Codes: H04R 2499/15 Transducers incorporated in visual displaying devices, e.g. televisions, computer displays, laptops
• CPC Class Codes: H04R 3/04 for correcting frequency response
• CPC Class Codes: H04S 2400/01 Multi-channel, i.e. more than two input channels, sound reproduction with two speakers wherein the multi-channel information is substantially preserved
• CPC Class Codes: H04S 2400/03 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 Class Codes: H04S 2400/11 Positioning of individual sound objects, e.g. moving airplane, within a sound field H04S2420/13 takes precedence
• CPC Class Codes: H04S 2420/01 Enhancing the perception of the sound image or of the spatial distribution using head related transfer functions [HRTF's] or equivalents thereof, e.g. interaural time difference [ITD] or interaural level difference [ILD]
• CPC Class Codes: H04S 2420/07 Synergistic effects of band splitting and sub-band processing
• CPC Class Codes: H04S 3/008 in which the audio signals are in digital form, i.e. employing more than two discrete digital channels data reduction aspects thereof based on psychoacoustics G10L19/02
• CPC Class Codes: H04S 7/303 Tracking of listener position or orientation
• CPC Class Codes: H04S 7/306 For headphones
• CPC Class Codes: H04S 7/307 Frequency adjustment, e.g. tone control H04S7/301 takes precedence

Abstract

The present invention relates to a method and an apparatus for processing an audio signal, and more particularly, to a method and an apparatus for processing an audio signal, which synthesizes an object signal and a channel signal and effectively binaural-render the synthesized signal.

To this end, the present invention provides a method for processing an audio signal, including: receiving an input audio signal including a multi-channel signal; receiving filter order information variably determined for each subband of a frequency domain; receiving block length information for each subband based on a fast Fourier transform length for each subband of filter coefficients for binaural filtering of the input audio signal; receiving Variable Order Filtering in Frequency-domain (VOFF) coefficients corresponding to each subband and each channel of the input audio signal per block of the corresponding subband, a total sum of lengths of the VOFF coefficients corresponding to the same subband and the same channel being determined based on the filter order information of the corresponding subband; and filtering each subband signal of the input audio signal by using the received VOFF coefficients to generate a binaural output signal and an apparatus for processing an audio signal by using the same.

Claims

1. A method for processing an audio signal, the method comprising:

receiving an input audio signal including a multi-channel signal;

receiving filter order information variably determined for each subband of a frequency domain;

receiving block length information for each subband based on a fast Fourier transform length for each subband of filter coefficients for binaural filtering of the input audio signal;

receiving Variable Order Filtering in Frequency-domain (VOFF) coefficients corresponding to each subband and each channel of the input audio signal per block of the corresponding subband, a total sum of lengths of the VOFF coefficients corresponding to the same subband and the same channel being determined based on the filter order information of the corresponding subband; and

filtering each subband signal of the input audio signal by using the received VOFF coefficients to generate a binaural output signal.

2. The method of claim 1, wherein the filter order is determined based on reverberation time information of the corresponding subband, which is obtained from proto-type filter coefficients, and

the filter order of at least one subband obtained from the same proto-type filter coefficients is different from the filter order of another subband.

3. The method of claim 1, wherein the length of the VOFF coefficients per block is determined as a value of power of 2 having the block length information of the corresponding subband as an exponent value.

4. The method of claim 1, wherein the generating of the binaural output signal further comprises:

partitioning each frame of the subband signal into subframe units determined based on the predetermined block length, and

performing fast convolution between the partitioned subframes and the VOFF coefficients.

5. The method of claim 4, wherein the length of the subframe is determined as a value which is a half as large as the predetermined block length, and

the number of partitioned subframes is determined based on a value obtained by dividing the total length of the frame by the length of the subframe.

6. An apparatus for processing an audio signal for performing binaural rendering of an input audio signal including a multi-channel signal, the apparatus comprising:

a fast convolution unit configured to perform rendering of direct sound and early reflection sound parts for the input audio signal, wherein the fast convolution unit is further configured to;

receive the input audio signal,

receive filter order information variably determined for each subband of a frequency domain,

receive block length information for each subband based on a fast Fourier transform length for each subband of filter coefficients for binaural filtering of the input audio signal,

receive Variable Order Filtering in Frequency-domain (VOFF) coefficients corresponding to each subband and each channel of the input audio signal per block of the corresponding subband, a total sum of lengths of the VOFF coefficients corresponding to the same subband and the same channel being determined based on the filter order information of the corresponding subband; and

filter each subband signal of the input audio signal by using the received VOFF coefficients to generate a binaural output signal.