Delay estimation method and apparatus

Patent metadata

Field	Value
Publication number	US-12520092-B2
Application number	US-202418590257-A
Country	US
Kind code	B2
Filing date	Feb 28, 2024
Priority date	Jun 29, 2017
Publication date	Jan 6, 2026
Grant date	Jan 6, 2026

Abstract

A delay estimation method includes determining a cross-correlation coefficient of a multi-channel signal of a current frame, determining a delay track estimation value of the current frame based on buffered inter-channel time difference information of at least one past frame, determining an adaptive window function of the current frame, performing weighting on the cross-correlation coefficient based on the delay track estimation value of the current frame and the adaptive window function of the current frame, to obtain a weighted cross-correlation coefficient, and determining an inter-channel time difference of the current frame based on the weighted cross-correlation coefficient.

First claim

What is claimed is:

1 . A method, comprising:
obtaining a current frame of a multi-channel signal, wherein the current frame comprises a left channel time domain signal and a right channel time domain signal; determining a cross-correlation coefficient of the current frame; determining, based on buffered inter-channel time difference (ITD) information of at least one past frame, a delay track estimation value of the current frame; determining an adaptive window function of the current frame, wherein the adaptive window function comprises a raised cosine-like window; performing, based on the delay track estimation value and the adaptive window function, weighting on the cross-correlation coefficient to obtain a weighted cross-correlation coefficient; determining, based on the weighted cross-correlation coefficient, an ITD of the current frame; obtaining an encoding index of the ITD; and writing the encoding index into an encoded bitstream.

2 . The method of claim 1 , wherein determining the adaptive window function comprises:
calculating, based on a first smoothed inter-channel time difference estimation deviation of a previous frame of the current frame, a first raised cosine width parameter; calculating, based on the first smoothed inter-channel time difference estimation deviation, a first raised cosine height bias; and determining, based on the first raised cosine width parameter and the first raised cosine height bias, the adaptive window function.

3 . The method of claim 2 , wherein the first raised cosine width parameter satisfies the following first calculation formula:

win_width
⁢
1

=

TRUNC
⁡
(

width_par
⁢
1
*

(

A
*
L_NCSHIFT
⁢
_DS

+
1

)

)

,

wherein width_par1=a_width1*smooth_dist_reg+b_width1,
wherein a_width1=(xh_width1−xl_width1)/(yh_dist1−yl_dist1),
wherein b_width1=xh_width1−a_width1*yh_dist1,
wherein win_width1 represents the first raised cosine width parameter,
wherein TRUNC indicates rounding a value,
wherein L_NCSHIFT_DS represents a first maximum value of an absolute value of the ITD,
wherein A is a preset constant and is greater than or equal to 4,
wherein xh_width1 represents a first upper limit value of the first raised cosine width parameter,
wherein xl_width1 represents a first lower limit value of the first raised cosine width parameter,
wherein yh_dist1 represents a second smoothed inter-channel time difference estimation deviation corresponding to the first upper limit value,
wherein yl_dist1 represents a third smoothed inter-channel time difference estimation deviation corresponding to the first lower limit value,
wherein smooth_dist_reg represents the first smoothed inter-channel time difference estimation deviation, and
wherein xh_width1, xl_width1, yh_dist1, and yl_dist1 are all positive numbers.

4 . The method of claim 3 , wherein width_par1=min (width_par1, xh_width1), wherein width_par1=max (width par1, xl_width1), wherein min represents taking a minimum value, and wherein max represents taking a second maximum value.

5 . The method of claim 3 , wherein the first raised cosine height bias satisfies the following second calculation formula:

win_bias
⁢
1

=

a_bias
⁢
1
*
smooth_dist
⁢
_reg

+

b_bias
⁢
1

,

wherein a_bias1=(xh_bias1−xl_bias1)/(yh_dist2−yl_dist2),
wherein b_bias1=xh_bias1−a_bias1*yh_dist2,
wherein win_bias1 represents the first raised cosine height bias,
wherein xh_bias1 represents a second upper limit value of the first raised cosine height bias,
wherein xl_bias1 represents a second lower limit value of the first raised cosine height bias,
wherein yh_dist2 represents a fourth smoothed inter-channel time difference estimation deviation corresponding to the second upper limit value,
wherein yl_dist2 represents a fifth smoothed inter-channel time difference estimation deviation corresponding to the second lower limit value, and
wherein yh_dist2, yl_dist2, xh_bias1, and xl_bias1 are all positive numbers.

6 . The method of claim 5 , wherein win_bias1=min (win_bias1, xh_bias1), wherein win_bias1=max (win_bias1, xl_bias1), wherein min represents taking a minimum value, and wherein max represents taking a second maximum value.

7 . The method of claim 5 , wherein yh_dist2=yh_dist1, and wherein yl_dist2=yl_dist1.

8 . The method of claim 1 , wherein the adaptive window function comprises:
when 0≤k≤TRUNC(A*L_NCSHIFT_DS/2)−2*win_width1−1, loc_weight_win(k)=win_bias1; when TRUNC(A*L_NCSHIFT_DS/2)−2*win_width1≤k≤TRUNC(A*L_NCSHIFT_DS/2)+2*win_width1−1, loc_weight_win(k)=0.5*(1+win_bias1)+0.5*(1−win_bias1)*cos(x*(k-TRUNC(A*L_NCSHIFT_DS/2))/(2*win_width1)); and when TRUNC(A*L_NCSHIFT_DS/2)+2*win_width1≤k≤A*L_NCSHIFT_DS, loc_weight_win(k)=win_bias1, wherein loc_weight_win(k) represents the adaptive window function, wherein k=0, 1, . . . , A*L_NCSHIFT_DS, wherein A represents a preset constant and is greater than or equal to 4, wherein L_NCSHIFT_DS represents a first maximum value of an absolute value of the ITD, wherein win_width1 represents a first raised cosine width parameter, and wherein win bias1 represents a first raised cosine height bias.

9 . A device, comprising:
one or more memories configured to store programming instructions; and one or more processors coupled to the one or more memories and configured to execute the instructions to:
obtain a current frame of a multi-channel signal, wherein the current frame comprises a left channel time domain signal and a right channel time domain signal;
determine a cross-correlation coefficient of the current frame;
determine, based on buffered inter-channel time difference (ITD) information of at least one past frame, a delay track estimation value of the current frame;
determine an adaptive window function of the current frame, wherein the adaptive window function comprises a raised cosine-like window;
perform, based on the delay track estimation value and the adaptive window function, weighting on the cross-correlation coefficient to obtain a weighted cross-correlation coefficient;
determine, based on the weighted cross-correlation coefficient, an ITD of the curr

Assignees

• Huawei Tech Co Ltd

Inventors

• Shlomot Eyal
• Li Haiting
• Miao Lei

Classifications

• H04S2400/05

  Generation or adaptation of centre channel in multi-channel audio systems · 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

• H04S5/00

  Pseudo-stereo systems, e.g. in which additional channel signals are derived from monophonic signals by means of phase shifting, time delay or reverberation · CPC title

• G10L25/03

  characterised by the type of extracted parameters · CPC title

• G10L25/78

  Detection of presence or absence of voice signals (switching of direction of transmission by voice frequency in two-way loud-speaking telephone systems H04M9/10) · CPC title