Sound spatialization with room effect

Patent metadata

Field	Value
Publication number	US-2016174013-A1
Application number	US-201414906311-A
Country	US
Kind code	A1
Filing date	Jul 4, 2014
Priority date	Jul 24, 2013
Publication date	Jun 16, 2016
Grant date	—

Abstract

A method of sound spatialization, in which at least one filtering process, including summation, is applied, to at least two input signals, the filtering process comprising: the application of at least one first room effect transfer function, the first transfer function being specific to each input signal, and the application of at least one second room effect transfer function, the second transfer function being common to all input signals. The method is such that it comprises a step of weighting at least one input signal with a weighting factor, said weighting factor being specific to each of the input signals.

First claim

1 : A method of sound spatialization, wherein at least one filtering process, with summation, is applied to at least two input signals, said filtering process comprising:
the application of at least one first room effect transfer function, said first transfer function being specific to each input signal, and the application of at least one second room effect transfer function, said second transfer function being common to all input signals,
wherein the method comprises a step of weighting at least one input signal with a weighting factor, said weighting factor being specific to each of the input signals.

2 : The method according to claim 1 , wherein said first and second transfer functions are respectively representative of:
direct sound propagations and the first sound reflections of said propagations; and a diffuse sound field present after said first reflections,
and wherein the method comprises:
the application of first transfer functions respectively specific to the input signals, and
the application of a second transfer function, identical for all input signals, and resulting from a general approximation of a diffuse sound field effect.

3 : The method according to claim 2 , comprising a preliminary step of constructing said first and second transfer functions from impulse responses incorporating a room effect, said preliminary step comprising, for the construction of a first transfer function, the operations of:
determining a start time of the presence of direct sound waves, determining a start time of the presence of said diffuse sound field after the first reflections, and selecting, in an impulse response, a portion of the response which extends temporally between said start time of the presence of direct sound waves to said start time of the presence of the diffuse field, said selected portion of the response corresponding to said first transfer function.

4 : The method according to claim 3 , wherein the second transfer function is constructed from a set of portions of impulse responses temporally starting after said start time of the presence of the diffuse field.

5 : The method according to claim 3 , wherein said second transfer function is given by applying a formula of the type:

B
mean
k

=

1
L



∑

l
=
1

L





[

B
norm
k



(
l
)

]

where k is the index of an output signal,
lε[1; L] is the index of an input signal,
L is the number of input signals,
B norm k (l) is a normalized transfer function obtained from a set of portions of impulse responses starting temporally after said start time of the presence of the diffuse field.

6 : The method according to claim 3 , wherein said filtering process includes the application of at least one compensating delay corresponding to a time difference between said start time of the direct sound waves and said start time of the presence of the diffuse field.

7 : The method according to claim 6 , wherein said first and second room effect transfer functions are applied in parallel to said input signals and wherein said at least one compensating delay is applied to the input signals filtered by said second transfer functions.

8 : The method according to claim 1 , wherein an energy correction gain factor is applied to the weighting factor.

9 : The method according to claim 1 , wherein at least one output signal of said method is given by applying a formula of the type:

O
k

=

∑

l
=
1

L





(

I


(
l
)

*

A
k



(
l
)

)

+

z

-
iDD

·

∑

l
=
1

L





(

1

W
k



(
l
)

·

I


(
l
)

)

*

B
mean
k

where k is the index of an output signal,
O k is an output signal,
lε[1; L] is the index of an input signal among said input signals,
L is the number of input signals,
I(l) is an input signal among said input signals,
A k (l) is

Assignees

• Orange

Inventors

• Pallone Gregory
• Emerit Marc

Classifications

• H04S2420/01

  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 title

• H04S2400/13

  Aspects of volume control, not necessarily automatic, in stereophonic sound systems · CPC title

• H04S7/306 Primary

  For headphones · CPC title

• H04S1/005 Primary

  For headphones · CPC title

• G10L19/008

  Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing · CPC title