ADSR envelope shaping on audio file
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I'm trying to apply ADSR envelope shaping to an audio file as shown below.
load handel y Fs;
N = 1.5 * Fs;
t = [0:N-1]/Fs;
x = y/Fs;
env = interp1([0 0.1 0.3 1.1 1.5], [0 1 0.4 0.4 0], t);
y = env .* x;
sound(y,Fs)
However, when performing the .* calculation, MATLAB freezes as the calculation is too large.
Could you assist in solving this problem? Thanks in advance.
采纳的回答
Mathieu NOE
2020-11-7
hi
so finally found the bug is due to improper t (time) definition
t is supposed to span from 0 to 1.5 according to the envelope specs, and have N samples
NB : the t and env lines must both have "1.5" in common otherwise there will be error msg
from there , everything runs smooth, the env is applied to the entire audio file
N);
see below :
load handel y Fs;
N = length(y);
t = linspace(0,1.5,N); % must be consistent with env definition below : [0 0.1 0.3 1.1 1.5]
env = interp1([0 0.1 0.3 1.1 1.5], [0 1 0.4 0.4 0], t);
env = env(:);
y = env .* y(:);
sound(y,Fs)
%
if you want to generalize the code and make it more robust , you should consider define the interp1 arguments as vectors
and generate t according to something like :
vect1 = [0 0.1 0.3 1.1 1.5];
vect2 = [0 1 0.4 0.4 0];
env = interp1(vect1, vect2, t);
t = linspace(vect1(1),vect1(end),N);
% so improved code suggestion
load handel y Fs;
N = length(y);
vect1 = [0 0.1 0.3 1.1 1.5];
vect2 = [0 1 0.4 0.4 0];
t = linspace(vect1(1),vect1(end),N);
env = interp1(vect1, vect2, t);
env = env(:);
y = env .* y(:);
sound(y,Fs)
更多回答(1 个)
Mathieu NOE
2020-11-6
ok
so simple problem of vector dimensions mismatch in your code
the env vector is either too short or the vector on which it is applied is too long
you have to modify one or the other
below my 2 cents suggestion, assuming N was supposed to be the number of samples extracted from the original file
also I didn't get why the line : x = y/Fs; this will simply reduce the amplitude of the output signal to almost zero
load handel y Fs;
N = round(1.5 * Fs); % why 1;5 ??
t = [0:N-1]/Fs;
% x = y/Fs; % why ??
env = interp1([0 0.1 0.3 1.1 1.5], [0 1 0.4 0.4 0], t);
env = env(:);
x_truncated = y(1:N); % only the first N samples of the audio file
x_truncated = x_truncated(:);
y = env .* x_truncated;
sound(y,Fs)
3 个评论
Mathieu NOE
2020-11-6
Was the size of the envelope supposed to equal the length of the total audio file ?
if yes you simply have to correct the t (time) vector length
N = length(y) ; (and not N = round(1.5 * Fs))
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