audio watermarking use a number as hide information in matlab

To audio watermarking using a number as hidden information in MATLAB, you can follow these steps:

1. Convert the audio signal into its frequency domain representation using the Fast Fourier Transform (FFT).
2. Select a specific frequency bin in the FFT representation to embed the watermark. This bin should be chosen carefully to minimize the perceptible impact on the audio quality.
3. Modify the magnitude or phase of the selected frequency bin to encode the hidden information. You can use the LSB (Least Significant Bit) technique, where the least significant bit of the magnitude or phase is altered to represent the binary value of the hidden information.
4. Apply the inverse FFT (IFFT) on the modified frequency domain representation to obtain the watermarked audio signal in the time domain.
5. Save the watermarked audio signal as a new audio file.

Here is a basic MATLAB code snippet that illustrates these steps:

main.m
% Load the audio signal
[inputAudio, fs] = audioread('inputAudio.wav');

% Convert audio signal to frequency domain
inputFFT = fft(inputAudio);

% Select a frequency bin to embed watermark
watermarkIndex = 100; % Choose an appropriate bin index

% Encode the watermark value into the magnitude of the selected frequency bin
watermarkValue = 7; % Example watermark value
inputFFT(watermarkIndex) = inputFFT(watermarkIndex) + watermarkValue;

% Obtain watermarked audio signal in the time domain
outputAudio = ifft(inputFFT);

% Save the watermarked audio signal to a new audio file
audiowrite('watermarkedAudio.wav', outputAudio, fs);
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Make sure to replace 'inputAudio.wav' with the path to your input audio file, and adjust the watermarkIndex and watermarkValue variables according to your requirements.

Note: This is a basic example and may not be robust to various signal processing attacks. For more robust and secure watermarking techniques, consider researching more advanced methods and algorithms.