Audio signal reading and manipulation

I have an audio file that i read.

I then want to take the first 5 samples and store them as a seperate array.

eample

[x,f] = audioread('speech.wav');

y1 = [x1 x2 x3 x4]

y2 =[x2 x3 x4 x5]

y3= [x3 x2 x4 x5]

yn = [ ect ]

this showing that array y1 has sample 1,2,3,4

array y2 has sample 2,3,4,5

ect.

i then want to make a loop that will effect all arrays

take array y1 and make it change the sample

array z1 = [x3 x2 x4 x1]

array z2 = [x4 x3 x5 x2]

ect

then comple all of the z1 arrays into a new audio file and play is

NS = [z1 z2 z3 z4 z5 z6 z7 ect...]

then play it

sound(NS,f)

ANY IDEAS ON HOW TO MAKE IT

Answer 1

[Mathieu NOE]

hello

this is my code but there are a few open questions

• why you say that we take 5 samples while y and z are vectors of 4 samples
• I suppose it's a typo but I guess y3= [x3 x2 x4 x5] is wrong and should be y3= [x3 x4 x5 x6]
• the resulting vector is about 4 times longer than the input vector but that's normal as each x vaues get's replicated multiple times in the output (z)

clc
clearvars
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% load signal
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%% data
[signal,Fs] = audioread('test_voice_mono.wav');

[samples,channels] = size(signal);
dt = 1/Fs;
time = (0:samples-1)*dt;

% extract four samples buffers with one sample shift
shift = 1;    % nb of samples shift between successive buffers
buffer = 4;    % nb of samples in one buffer 
N = fix((samples-buffer)/shift +1);
z_all = [];

for ci=1:N
    start_index = 1+(ci-1)*shift;
    stop_index = min(start_index+ buffer-1,samples);
    y =signal(start_index:stop_index,:);  % 4 contiguous samples (y1 = [x1 x2 x3 x4])
    % flip values so that it becomes : z1 = [x3 x2 x4 x1]
    ind = [3;2;4;1];
    z = y(ind);
    % concatenate all z vectors
    z_all = [z_all; z];

end

% audiowrite('out.wav',z_all,Fs);
sound(z_all,Fs)

[Lane Smith]

Thank you so much. this helps alot!

[Mathieu NOE]

My pleasure !

do you mind accepting my answer ?