FFT calculation suitable, Wav File, Java If I have a wav file with this characteristics:


16bits (2 Bytes per Sample)
32000 Sampling Rate
60 Seconds
2 Channels


then I have:

Samples Per Channel: 32000*60 = 1920000
Samples Per File: 32000*60*2 = 3840000
Bytes Per File: 32000*60*2*2 = 7680000


It's a huge file!

If I change my file Characteristics to:


8bits (1 Byte per Sample)
8000 Sampling Rate
60 Seconds
1 Channel


then I have:

Samples Per Channel: 8000*60 = 480000
Samples Per File: 8000*60*1 = 480000
Bytes Per File: 8000*60*1*1 = 480000


If my FFT 2^12 = 4096 or 2^16 = 65536

Do I need to calculate the FFT 480000 times?

Does each how many samples I need to calculate the FFT?  (480000 - 65536 = 414464?)

what is the suitable calculus?

How to do to show the spectrum?
To show only one spectrum then FFT of the whole sample could be done.But for better result you could take a window and take FFT. For taking windows of 4096 with 50% overlap then it is equivalent to doing FFT
no of times
$$
\frac{480000}{4096*0.5}
$$
times that is equivalent to
$$
\frac{Total\hspace{1mm} sample\hspace{1mm} length}{(window \hspace{1mm}length)*(amount\hspace{1mm} of\hspace{1mm} overlap)}
$$