Audio to binary conversion

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Sara MH 2017-12-26

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/374558-audio-to-binary-conversion

编辑： Walter Roberson 2018-1-12

采纳的回答： Walter Roberson

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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?

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Image Analyst 2017-12-26

Have you tried bitget()?

Sara MH 2017-12-26

it gives Undefined function 'bitget' for input arguments of type 'char'. as i tried to put wavebinary =bitget(filename);

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Walter Roberson 2017-12-26

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https://ww2.mathworks.cn/matlabcentral/answers/374558-audio-to-binary-conversion#answer_297732

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

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Walter Roberson 2018-1-7

在 MATLAB Online 中打开

The code I gave previously,

wavebinary = dec2bin( typecast( single(soundata(:)), 'uint8'), 8 ) - '0';

converts to an N x 8 numeric array. If you embedded that into a file, you would have had to do so as a vector, which would have require that you choose a sequence to use the bits from the array -- which could have been that you went across the rows so that all information from a particular sample is grouped together, or it could have been that you went down the columns, as that would be the normal MATLAB order of addressing the bits.

I think it likely that if you are having difficulty reversing the line of code I showed here, that you are probably also having difficulty getting the extracted bits together into the proper order to turn back into sound. In order for us to help you with that, you will have to describe the order that the wavebinary bits were stored in the file.

Is the size of the sound that you embed a constant, or are you also embedding bits indicating what the size is? You need the size information in order to extract the information properly. At the very least you need to know how many channels and you need to know the point at which the embedding stops so that you do not end up extracting bits that were never set.

Sara MH 2018-1-12

can i contact you? i want some help in this

Walter Roberson 2018-1-12

编辑：Walter Roberson 2018-1-12

No, I prefer questions to be posted in public. Also, I am not interested in steganography itself.

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