I need to
- read a
- make a 2D matrix from it using the STFT
- generate its singular value decomposition
- do some watermarking
but I can't build the original matrix again via matrix multiplication:
x = audioread('0.wav'); stft = spectrogram(x); [U,S,V] = svd(stft); stftb=U*S*V.';
The problem is that STFT and STFTb are not the same.