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| + | Sound file [[Image:Example_ECE301Fall2008mboutin.jpg]] | ||
| + | == MATLAB code == | ||
| + | |||
| + | <pre> | ||
| + | % Ben Laskowski (blaskows@purdue.edu) | ||
| + | % September 5, 2008 | ||
| + | % ECE301 Section 2 HW1 | ||
| + | % | ||
| + | % This file is supposed to reverse and slow a wav file for extraction of | ||
| + | % alleged subliminal messages. | ||
| + | |||
| + | % Begin by clearing the output console and all memory. | ||
| + | clear; | ||
| + | clc; | ||
| + | |||
| + | %Open the wave file and get its length, sample size, and sampling rate | ||
| + | [data,fs,nbits]=wavread('jpforward.wav'); | ||
| + | |||
| + | %Play the file once normally | ||
| + | disp('Playing the unaltered file...') | ||
| + | wavplay(data,fs); | ||
| + | |||
| + | %Reverse the file, play it, and write it out | ||
| + | Length=size(data); | ||
| + | MaxCount=Length(1); | ||
| + | reversedata=zeros(MaxCount,1); | ||
| + | for counter=MaxCount:-1:1 | ||
| + | reversedata(MaxCount-counter+1,1)=data(counter); | ||
| + | end | ||
| + | disp('Playing reverse at normal speed...'); | ||
| + | wavplay(reversedata,fs); | ||
| + | |||
| + | |||
| + | %To slow the original data, we can just write out the reversed data with | ||
| + | % a fraction of the correct sampling rate. | ||
| + | disp('Playing reverse at 67% speed...'); | ||
| + | wavwrite(reversedata,fs/1.5,nbits,'jpreverseslow.wav'); | ||
| + | wavplay(reversedata,fs/1.5); | ||
| + | |||
| + | </pre> | ||
Latest revision as of 11:40, 2 September 2008
Sound file 
MATLAB code
% Ben Laskowski (blaskows@purdue.edu)
% September 5, 2008
% ECE301 Section 2 HW1
%
% This file is supposed to reverse and slow a wav file for extraction of
% alleged subliminal messages.
% Begin by clearing the output console and all memory.
clear;
clc;
%Open the wave file and get its length, sample size, and sampling rate
[data,fs,nbits]=wavread('jpforward.wav');
%Play the file once normally
disp('Playing the unaltered file...')
wavplay(data,fs);
%Reverse the file, play it, and write it out
Length=size(data);
MaxCount=Length(1);
reversedata=zeros(MaxCount,1);
for counter=MaxCount:-1:1
reversedata(MaxCount-counter+1,1)=data(counter);
end
disp('Playing reverse at normal speed...');
wavplay(reversedata,fs);
%To slow the original data, we can just write out the reversed data with
% a fraction of the correct sampling rate.
disp('Playing reverse at 67% speed...');
wavwrite(reversedata,fs/1.5,nbits,'jpreverseslow.wav');
wavplay(reversedata,fs/1.5);
