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Institute of Technical Acoustics (ITA)
toolbox
Commits
c1c9fdc9
Commit
c1c9fdc9
authored
Jan 18, 2017
by
Michael Kohnen
Browse files
Added Ambisonics implementation
parent
483d6b05
Changes
2
Hide whitespace changes
Inline
Side-by-side
applications/SpatialAudio/ita_decodeAmbisonics.m
0 → 100644
View file @
c1c9fdc9
function
[
loudspeakerSignals
]
=
ita_decodeAmbisonics
(
Bformat
,
LoudspeakerPos
,
varargin
)
%ITA_DECODEAMBISONICS Summary of this function goes here
% Detailed explanation goes here
opts
.
decoding
=
'remax'
% Decoding strategy (remax,inphase,plane)
opts
=
ita_parse_arguments
(
opts
,
varargin
);
% Initializing further parameters
nmax
=
numel
(
Bformat
);
% Weighting for Inphase/ReMax
g_re
=
ones
(
nmax
,
1
);
%init weighting factors for ReMax
g_in
=
g_re
;
%init weighting factors for InPhase
% ReMax Decoding
if
(
sum
(
strcmp
(
lower
(
opts
.
decoding
),{
'remax'
'both'
})))
% Calculates the B-Format channel weights for ReMax-Decoding
% see J.Daniel Thesis p.312 A.67/A.68
weightsReMax
=
zeros
(
nmax
,
1
);
% init weights
% g_m=P_m(r_E) with n=0 for P
% r_E is largest root of P_(order+1)
syms
x
;
f
=
1
/
2
^
(
TheOrder
+
1
)/
factorial
(
TheOrder
+
1
)
*
diff
(((
x
^
2
-
1
)
^
(
TheOrder
+
1
)),(
TheOrder
+
1
));
%Legendre Polynom n=0 m=order+1
maxroot
=
max
(
eval
(
solve
(
f
)));
%find maximum root(Nullstelle)
for
k
=
1
:
nmax
leggie
=
legendre
(
ita_sph_linear2degreeorder
(
k
),
abs
(
maxroot
));
% g_m=P_m(r_E)
weightsReMax
(
k
)
=
leggie
(
1
);
% pick n=0
end
g_re
=
weightsReMax
;
end
% Inphase Decoding
if
(
sum
(
strcmp
(
lower
(
opts
.
decoding
),{
'inphase'
'both'
})))
% Calculates the B-format channel weights for InPhase-Decoding
TheOrder
=
obj
.
ambGetOrder
;
% amb order from sim room
nmax
=
(
TheOrder
+
1
)
^
2
;
% number of channels
weightsInPhase
=
zeros
(
nmax
,
1
);
N
=
numel
(
obj
.
monitorRoom
.
getSourcePosition
)/
3
;
% get number of loudspeaker
%Dissertation J.Daniel p.314, 'preserve Energy' in 0. order
%g_0=sqrt[N*(2*M+1)/(M+1)^2]
weightsInPhase
(
1
)
=
sqrt
(
N
*
(
2
*
TheOrder
+
1
)/(
TheOrder
+
1
)
^
2
);
for
k
=
2
:
nmax
m
=
ita_sph_linear2degreeorder
(
k
);
% Dissertation J.Daniel p.314
% g_m=M!*(M+1)!/[(M+m+1)!*(M-n)!]
weightsInPhase
(
k
)
=
factorial
(
TheOrder
)
*
factorial
(
TheOrder
+
1
)/
factorial
(
m
+
TheOrder
+
1
)/
factorial
(
TheOrder
-
m
);
end
g_in
=
weightsInPhase
;
end
weights
=
g_in
.*
g_re
;
%merge weighting factors
for
k
=
1
:
numel
(
weights
)
Bformat
(:,
k
)
=
weights
(
k
)
.*
Bformat
(:,
k
);
%Apply weighting factors
end
% SH and inversion
Y
=
ita_sph_base
(
LS
,
TheOrder
,
'williams'
,
false
);
% generate basefunctions
Yinv
=
pinv
(
Y
);
% calculate Pseudoinverse
if
isa
(
Bformat
,
'itaAudio'
)
for
k
=
1
:
LS
.
nPoints
OutputSignals
(
k
)
=
sum
(
Bformat
*
Yinv
(:,
k
)
'
);
end
OutputSignals
=
ita_merge
(
OutputSignals
(:));
else
OutputSignals
=
Bformat
*
Yinv
;
end
end
applications/SpatialAudio/ita_encodeAmbisonics.m
0 → 100644
View file @
c1c9fdc9
function
[
Bformat
]
=
ita_encodeAmbisonics
(
sourcePos
,
varargin
)
%ITA_ENCODEAMBISONICS Summary of this function goes here
% Detailed explanation goes here
if
nargin
<
1
error
(
'Source position is needed as itaCoordiantes!'
);
end
if
~
isa
(
sourcePos
,
'itaCoordinates'
)
error
(
'First input data has to be an itaCoordinates!'
)
elseif
isempty
(
sourcePos
.
cart
)
error
(
'First input data has to be an itaCoordinates WITH inputdata!'
)
end
opts
.
order
=
1
;
%Ambisonics truncation order
opts
.
audioSource
=
''
;
%Signal of the source (itaAudio or filename)
opts
=
ita_parse_arguments
(
opts
,
varargin
);
% Encode Source
Bformat
=
ita_sph_base
(
sourcePos
,
opts
.
order
,
'Williams'
,
false
);
if
~
isempty
(
opts
.
audioSource
)
if
isa
(
opts
.
audioSource
,
'char'
)
audioIn
=
ita_read
(
opts
.
audioSource
);
elseif
isa
(
opts
.
audioSource
,
'itaAudio'
)
audioIn
=
opts
.
audioSource
;
elseif
~
isa
(
audioIn
,
'itaAudio'
)
error
(
'Audio input must eihter be itaAudio or valid filename (see ita_read)'
);
end
audioOut
=
audioIn
*
Bformat
(
1
);
for
k
=
2
:
numel
(
Bformat
)
audioOut
=
ita_merge
(
audioOut
,
audioIn
*
Bformat
(
k
));
end
Bformat
=
audioOut
;
end
end
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