Audio watermarking

Thread Starter

medek

Joined Aug 7, 2008
5
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.
 

beenthere

Joined Apr 20, 2004
15,819
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.
 

Dave

Joined Nov 17, 2003
6,969
[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.
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
 

CVMichael

Joined Aug 3, 2007
419
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.
 

Thread Starter

medek

Joined Aug 7, 2008
5
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
 

Thread Starter

medek

Joined Aug 7, 2008
5
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
 

Thread Starter

medek

Joined Aug 7, 2008
5
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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