test_3.m

audio compression matlab code

clf;clc; clf;
% use "f_bit_compress" and "f_bit_expand" functions ...

p = 'D:\adorel\a_master_DATA_COMPRESS\standard_test_audio\';
filename = 'Windows XP Startup.wav';

file = strcat(p,filename);
[I_all,fs,nbits, opts] = wavread(file);
I_all = (I_all(:,1) + I_all(:,2) )./2;

Ns = length(I_all);
% Ns = 0.8*1e5;
Ns = 80;
a = I_all(1000:1000+Ns-1);
t = (0:Ns-1).*(1/fs);

nbits_in = 16;
nbits_out = 8;

% transfer characteristic ...
x = -max(I_all) : 0.01: max(I_all);
xc = f_bit_compression(x, nbits_in, nbits_out);
subplot(221), stairs(x,xc)


% test with an input signal ...
[y] = f_bit_compression(a, nbits_in, nbits_out);
subplot(222), plot(t,a,t,y,'r');