Audio Watermarking in MATLAB - How to choose frames to embed in? Hello I am working on audio watermarking in MATLAB and am trying to choose specific frames of the audio signal where the watermark will be embedded. Through research, I have read that the best way to do this is to choose parts/samples of the audio signal that are the loudest, or above a certain threshold. By using wavread in MATLAB, the result is an array of the audio data in type double precision, which represent the sound pressure at a given sample. My question is, since the numbers represent sound pressure, will the loudest portions of the audio signal be the largest numbers? If not, is there another way to achieve what I am trying to do? Thank you!
Loudness is defined as human perception of volume. In general, there is a very good correspondence between the two. Therefore, you can often use one as a proxy for the other.

In this case, you can easily measure volume: the portions of the audio signal with the highest signal intensity (or volume) correspond to the parts with the greatest absolute value (or, if you prefer, square value). With a few assumptions, you can say that the loud sections are also the sections with high volume.