Question

What does a sample of a audio file contain ?

When I run the command “sox file.wav -r 10 file.dat”, the output is something like

; Sample Rate 10
; Channels 2
           0    0.00085449219   -0.0007019043
         0.1       0.01348877    -0.011260986
         0.2      0.015930176    -0.013214111
         0.3      0.014923096    -0.012390137
         ...      ...            ...

I know the first column is time the second and third column stand for the 2 channels.

But I would like to know is what does the channel value contain ?

Answer 1

Have a look here: http://www.hardwaresecrets.com/article/317. In short…if you think of a membrane of a loudspeaker, each sample is a measure of the position of the membrane at a moment in time. E.g. for that reason a sample does not represent the sound level directly. However the level of the audio signal can be calculated with the sample information, e.g. implementing a peak program meter algorithm: http://en.wikipedia.org/wiki/Peak_programme_meter