MATLAB common code in Audio

audioCommon.m

%% Updated on Jun., 2017 ------------------------------------------------
%   Copyright by Jarvus Chen. All Rights Reserved.
%   www.jarvus.net

%% Read and Plot ---------------------------------------------------------
clear
clc
close all

% read audio file
[ clean, fs ] = wavread( 'speech.wav' );

s_length = length(clean);      % get the amount of all samples
sampleTime = ( 1:s_length )/fs;% transfer sample amount to its time
frameSize = fix(0.020*fs);      % window length is 20 ms
NFFT = 2*frameSize;             % FFT size is twice the window length

figure;
% plot audio in time domain
plot(sampleTime, clean);
title(['Signal - clean speech'])
xlabel('Time (s)');ylabel('Amplitude');

figure;
% plot audio in frequency domain
% use hanning window and 50% overlap
[B,f,T] = specgram(clean,NFFT,fs,hanning(frameSize),frameSize/2);
imagesc(T,f,20*log10(abs(B)));axis xy;colorbar
title(['Spectrogram - clean speech'])
xlabel('Time (s)');ylabel('Frequency (Hz)');


%% Scale and Write ---------------------------------------------------------

% scale your max amplitude to (0~1)
ampScale = 0.7;
out = zeros(s_length,1);
if max(clean) > abs(min(clean))
    out = clean*(ampScale/max(clean));
else
    out = clean*((-ampScale)/min(clean));
end


% write new audio file
wavwrite(out,fs,16,'output.wav');

%% change the sample rate of audio ---------------------------------------------------------
fs_from = 44100;
fs_to = 16000;
[P,Q] = rat(fs_to/fs_from);
clean16 = resample(clean, P, Q);

%% align two signal which are with time delay ---------------------------------------------------------

% masked is another signal which is time delay 
% or a little different by clean
% clean_m and masked_m is modified signal which are aligned
[clean_out ,masked_out] = alignsignals(clean, masked);
[pos] = find(masked_out ~= 0);
clean_out = clean_out(pos(1):length(clean));
masked_out = masked_out(pos(1):length(clean));