Method for generating filter for audio signal, and parameterization device for same

• US 10,158,965 B2
• Filed: 10/21/2017
• Issued: 12/18/2018
• Est. Priority Date: 12/23/2013
• Status: Active Grant

• Current Assignee: GCOA Company Limited, WILUS Inc.
• Original Assignee: WILUS Inc.
• Inventors: Lee, Taegyu, Oh, Hyunoh
• Primary Examiner(s): Laekemariam, Yosef K
• Application Number:
  US15/789,960
• Publication Number:
  US 20180048981A1
• Time in Patent Office: 423 Days
• Field of Search: 381 1, 381 17, 381 18, 381 23, 381 61, 381 63, 381306, 381307, 381309
• 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 19/0204 using subband decomposition
• 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 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 2420/03 Application of parametric coding in stereophonic audio systems
• 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 7/305 Electronic adaptation of stereophonic audio signals to reverberation of the listening space H04S7/301 takes precedence
• CPC Class Codes: H04S 7/307 Frequency adjustment, e.g. tone control H04S7/301 takes precedence

Abstract

The present invention relates to a method for generating a filter for an audio signal and a parameterization device for the same, and more particularly, to a method for generating a filter for an audio signal, to implement filtering of an input audio signal with a low computational complexity, and a parameterization device therefor.

To this end, provided are a method for generating a filter for an audio signal, including: receiving at least one binaural room impulse response (BRIR) filter coefficients for binaural filtering of an input audio signal; converting the BRIR filter coefficients into a plurality of subband filter coefficients; obtaining average reverberation time information of a corresponding subband by using reverberation time information extracted from the subband filter coefficients; obtaining at least one coefficient for curve fitting of the obtained average reverberation time information; obtaining flag information indicating whether the length of the BRIR filter coefficients in a time domain is more than a predetermined value; obtaining filter order information for determining a truncation length of the subband filter coefficients, the filter order information being obtained by using the average reverberation time information or the at least one coefficient according to the obtained flag information and the filter order information of at least one subband being different from filter order information of another subband; and truncating the subband filter coefficient by using the obtained filter order information and a parameterization device therefor.

Claims

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

receiving an input audio signal;

receiving a set of binaural room impulse response (BRIR) filter coefficients for binaural filtering of the input audio signal;

converting the set of BRIR filter coefficients into a plurality of sets of subband filter coefficients;

obtaining flag information indicating whether the length of the set of BRIR filter coefficients is more than a predetermined value in a time domain;

truncating each set of subband filter coefficients based on filter order information obtained by at least partially using characteristic information extracted from the corresponding set of subband filter coefficients, wherein an energy compensation is performed to the truncated set of subband filter coefficients based on the flag information, and each length of the truncated set of subband filter coefficients is variably determined in a frequency domain; and

filtering each subband signal of the input audio signal by using the truncated set of subband filter coefficients corresponding thereto.

2. The method of claim 1, wherein the energy compensation is performed when the flag information indicates that the length of the set of BRIR filter coefficients is not more than a predetermined value.

3. The method of claim 1, wherein the energy compensation is performed by dividing the truncated set of subband filter coefficients by filter power up to a truncation point, and multiplying total filter power of the corresponding set of subband filter coefficients, and

wherein the truncation point is determined based on the filter order information.

4. The method of claim 1, wherein the method further comprises:

performing reverberation processing of each subband signal corresponding to a period subsequent to the truncated set of subband filter coefficients among the set of subband filter coefficients when the flag information indicates that the length of the set of BRIR filter coefficients is more than the predetermined value.

5. The method of claim 1, wherein the characteristic information comprises reverberation time information of the corresponding set of subband filter coefficients and the filter order information has a single value for each subband.

6. An apparatus for processing an audio signal, comprising:

a parameterization unit configured to generate a filter for an audio signal; and

a binaural rendering unit configured to receive an input audio signal and filter the input audio signal by using parameters generated by the parameterization unit,

wherein the parameterization unit is further configured to;

receive a set of binaural room impulse response (BRIR) filter coefficients for binaural filtering of the input audio signal,

convert the set of BRIR filter coefficients into a plurality of sets of subband filter coefficients,

obtain flag information indicating whether the length of the set of BRIR filter coefficients is more than a predetermined value in a time domain,

truncate each set of subband filter coefficients based on filter order information obtained by at least partially using characteristic information extracted from the corresponding set of subband filter coefficients, wherein an energy compensation is performed to the truncated set of subband filter coefficients based on the flag information, and each length of the truncated set of subband filter coefficients is variably determined in a frequency domain, and

wherein the binaural rendering unit is further configured to filter each subband signal of the input audio signal by using the truncated set of subband filter coefficients corresponding thereto.

7. The apparatus of claim 6, wherein the energy compensation is performed when the flag information indicates that the length of the set of BRIR filter coefficients is not more than a predetermined value.

8. The apparatus of claim 6, wherein the energy compensation is performed by dividing the truncated set of subband filter coefficients by filter power up to a truncation point, and multiplying total filter power of the corresponding set of subband filter coefficients, and

wherein the truncation point is determined based on the filter order information.

9. The apparatus of claim 6, wherein the binaural rendering unit is further configured to perform reverberation processing of each subband signal corresponding to a period subsequent to the truncated set of subband filter coefficients among the set of subband filter coefficients when the flag information indicates that the length of the set of BRIR filter coefficients is more than the predetermined value.

10. The apparatus of claim 6, wherein the characteristic information comprises reverberation time information of the corresponding set of subband filter coefficients and the filter order information has a single value for each subband.

11. A parameterization device for generating a filter for an audio signal, the parameterization device is configured to:

receive a set of binaural room impulse response (BRIR) filter coefficients for binaural filtering of an input audio signal,

convert the set of BRIR filter coefficients into a plurality of sets of subband filter coefficients,

obtain flag information indicating whether the length of the set of BRIR filter coefficients is more than a predetermined value in a time domain,

truncate each set of subband filter coefficients based on filter order information obtained by at least partially using characteristic information extracted from the corresponding set of subband filter coefficients, wherein an energy compensation is performed to the truncated set of subband filter coefficients based on the flag information, and each length of the truncated set of subband filter coefficients is variably determined in a frequency domain.

12. The device of claim 11, wherein the energy compensation is performed when the flag information indicates that the length of the set of BRIR filter coefficients is not more than a predetermined value.

13. The device of claim 11, wherein the energy compensation is performed by dividing the truncated set of subband filter coefficients by filter power up to a truncation point, and multiplying total filter power of the corresponding set of subband filter coefficients, and

wherein the truncation point is determined based on the filter order information.

14. The device of claim 11, wherein the characteristic information comprises reverberation time information of the corresponding set of subband filter coefficients and the filter order information has a single value for each subband.