MATLAB: Audio to binary conversion

#audio #conversion #binary

Hello

i'm working on a project related to steganography ( audio steganography), and at first i want to convert an existing wav file to audio and extract the LSB's of it using a MATLAB script. how can i start?

i used this code:

[filename, pathname] = uigetfile('*.wav', 'Pick an audio');
wavebinary = dec2bin( typecast( single(filename(:)), 'uint8'), 8 ) - '0';
[r c] = size(wavebinary);
wavb= [];
wavd=[];
for k=1:r
    wavb=horzcat(num2str(wavebinary(k,1:8),wavb));
      x=bin2dec(wavb(1:8));
      wavd=horzcat(x,wavd);
      wavb=[];
  end
  wavd=fliplr(wavd);

it gives me a 36*8 martix don't know why

and i need more samples.. how can i do that?

Best Answer

Your code never reads the file. Your code is transforming the file NAME to binary.

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MATLAB: Randomly picking some files

You can get a directory and then use randperm to get a list of random, non-repeated indexes, or randi to get a list of possibly repeated indexes, or you can use this program I wrote that will play either a random wave file or one that you specify:

% Play a wav file.  You can pass in 'random' and it will pick one at random from the folder to play.
% PlaySoundFile(handles.soundFolder, 'chime.wav');
% PlaySoundFile(handles.soundFolder, 'random');
function PlaySoundFile(soundFolder, baseWavFileName)
  try        % Read the sound file into MATLAB, and play the audio.
%     soundFolder = fullfile(soundFolder, 'Sound Files');
    if ~exist(soundFolder, 'dir')
        warningMessage = sprintf('Warning: sound folder not found:\n%s', soundFolder);
        WarnUser(warningMessage);
        return;
    end
    if strcmpi(baseWavFileName, 'random')
      itWorked = false;
      tryCount = 1;
      while itWorked == false
        % Pick a file at random.
        filePattern = fullfile(soundFolder, '*.wav');
        waveFiles = dir(filePattern);
        numberOfFiles = length(waveFiles);
        % Get a random number
        fileToPlay = randi(numberOfFiles, 1);
        baseWavFileName = waveFiles(fileToPlay).name;
        fullWavFileName = fullfile(soundFolder, baseWavFileName);
        waveFileData = -1;
        try
          if exist(fullWavFileName, 'file')
            [waveFileData, Fs, nbits, readinfo] = wavread(fullWavFileName);
            sound(waveFileData, Fs);
            %     soundsc(y,Fs,bits,range);


          else
            warningMessage = sprintf('Warning: sound file not found:\n%s', fullWavFileName);
            WarnUser(warningMessage);
          end
          % It worked.  It played because the audio format was OK.
          itWorked = true;
        catch
          % Increment the try count and try again to find a file that plays.
          tryCount = tryCount + 1;
          if tryCount >= numberOfFiles
            break;
          end
        end
      end % of while()
    else
  %     baseWavFileName = 'Chime.wav';
      fullWavFileName = fullfile(soundFolder, baseWavFileName);
      waveFileData = -1;
      if exist(fullWavFileName, 'file')
        [waveFileData, Fs, nbits, readinfo] = wavread(fullWavFileName);
        sound(waveFileData, Fs);
        %     soundsc(y,Fs,bits,range);
      else
        warningMessage = sprintf('Warning: sound file not found:\n%s', fullWavFileName);
        WarnUser(warningMessage);
      end
    end
  catch ME
    if strfind(ME.message, '#85')
      % Unrecognized format.  Play chime instead.      
      fprintf('Error in PlaySoundFile(): %s.\nUnrecognized sound format in file:\n\n%s\n', ME.message, fullWavFileName);
       baseWavFileName = 'Chime.wav';
      fullWavFileName = fullfile(soundFolder, baseWavFileName);
      waveFileData = -1;
      if exist(fullWavFileName, 'file')
        [waveFileData, Fs, nbits, readinfo] = wavread(fullWavFileName);
        sound(waveFileData, Fs);
        %     soundsc(y,Fs,bits,range);
      end
    end
    errorMessage = sprintf('Error in PlaySoundFile().\nThe error reported by MATLAB is:\n\n%s', ME.message);
    fprintf('%s\n', errorMessage);
    WarnUser(errorMessage);
  end
  return; % from PlaySoundFile

By the way, WarnUser is simply

function WarnUser(message)
uiwait(warndlg(message));

MATLAB: I want to convert a .wav file to binary,modulate it,transmit,demodulate and convert the binary back to .wav file.But I am not able to write binary data back to wav file.

Which release are you using? R2016a was the last release that accepted by initial phase (0) and symbol order (gray) for qammod, with R2016b being the last release that permitted initial phase.

In current releases, the default output for qamdemod is integer, and the integers can be anywhere from 0 to M-1 where M is the order you passed (which is 16 in your case). Current releases have an option 'outputtype', 'bit'

But when you qammod(), in current releases the default input is integer as well, and you would need 'inputtype', 'bit' to specify bits.

Which is to say, you are currently telling qammod that your inputs are integers in the range 0 to 15, but it just happens that none of them are anything other than 0 or 1. You then add white noise and decode. But the white noise might happen to knock some of the symbols into a different constellation, so you when you qamdemod you can get back integers other than what you put in.

If you were using modern MATLAB, you would

xmod=qammod(w1, 16, 'gray', 'inputtype', 'bit');

and

rdmod=qamdemod(y1, 16, 'gray', 'outputtype', 'bit');

and the problem with bin2dec would no longer occur.

Best Answer

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MATLAB: Randomly picking some files

MATLAB: I want to convert a .wav file to binary,modulate it,transmit,demodulate and convert the binary back to .wav file.But I am not able to write binary data back to wav file.

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