Audio watermarking

Discussion in 'Programmer's Corner' started by medek, Sep 29, 2008.

  1. medek

    Thread Starter New Member

    Aug 7, 2008
    5
    0
    guys, i need help. i'm doing my project on audio watermarking using LSB technique. as for the start, i'm not sure how to put my audio and change it to bit. should i use this code?

    [m d] = wavinfo (filename)
    [y,Fs,bits] = wavread (filename)

    and if it is correct, what is m, d, y, Fs stands for? i dont understand.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Greetings! And welcome to AAC.

    Please refrain from "hijacking" existing threads. You can create new threads for new questions using the "New Thread" button on the upper left of the page.
     
  3. Dave

    Retired Moderator

    Nov 17, 2003
    6,960
    144
    Never come across wavinfo. For wavread:

    y is the sampled data from the wav-file, Fs is the sampling frequency, and bits is the number of bits per sample.

    Dave
     
  4. CVMichael

    Senior Member

    Aug 3, 2007
    416
    17
    LSB technique is mostly used for images.

    For sound it is difficult to preserve the watermark when you copy the sound by recoding it. Only a file copy will preserve the watermark.

    LSB basically means you are mixing the original with the watermark, the tricky part is detecting your watermark afterwords. So when you mix you have to leave a significant amount so you can detect it programmatically but not enough to detect it by ear (listening to it).

    Anyways, you did not say in what programing language you want to do it ???

    I have a tutorial about sound, but it is for Visual Basic 6.
    I have the tutorial here on vbforums.com: VB6.0 – Sound and DirectXSound Tutorial
    And also on CodeGuru: Sound and DirectXSound Tutorial

    At the end of the tutorial is how to mix sounds, but you should know everything before that to be able to do it.
     
  5. medek

    Thread Starter New Member

    Aug 7, 2008
    5
    0
    thnx guys..
    im doing it in MATLAB..
    im learning it now, hopefully i can come up with something.
     
  6. medek

    Thread Starter New Member

    Aug 7, 2008
    5
    0
    guys, i tried with this code:

    [m d] = wavfinfo('type.wav');
    [y, Fs, nbits] = wavread('type.wav')

    the output is like this:

    -0.3125
    -0.2578
    -0.1875
    -0.0859
    0.0234
    ...
    ...

    how can i come out with this output pattern in binary:?

    1 0 0 1 0 1 0 0 0 1 0 0 1 1 0 0
    0 0 1 0 1 0 1 0 1 1 1 1 1 1 1 1
    1 0 0 0 0 0 0 0 0 0 0 1 1 0 1 1
    0 1 1 1 1 1 1 1 0 0 1 0 1 0 1 0
    0 0 0 0 0 0 1 1 1 0 1 0 1 1 0 1
    0 1 1 1 0 1 0 1 0 1 0 1 0 1 0 1
    ...
    ...
    ...

    thank you
     
  7. medek

    Thread Starter New Member

    Aug 7, 2008
    5
    0
    thanx guys..
    sorry for the late reply coz i've been very busy with my subjects.
    im doing audio watermarking using DWT method rite now. I couldnt find the flow or how to start. can anyone provide me some knowledge or links for me to learn? it would be very helpful
     
  8. medek

    Thread Starter New Member

    Aug 7, 2008
    5
    0
    guys, i have to test my audio watermarking technique to see if it is robust, fragile and invisible. how can i do that? can anyone provide me with some source or clue? it would be very helpful. thanx
     
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