pfft timing

Hello,

I find pfft to be a bit of a mystery in terms of the timing of the frequency domain in each successive frame.

For example suppose I have an fft size of 1024 with an overlap of 2, the fftin~ object will give 512 real and imaginary numbers (at the audio rate I presume?) which corresponds to 1024 samples of time domain audio half of which will be overlapped with the subsequent frame.

My question concerns what happens with the timing of the subsequent frame. My guess is that after the 512 real and imaginary vales of the previous frame have been output by fttin~ the next 512 value pairs follow corresponding to another 1024 samples of audio but now 512 samples later in ‘audio time’ if that makes sense.

This would fit in with my tendency to view the workings of my inner pfft subpatch as operating as one instance, so for example if I was writing fft data to a buffer I wouldn’t have data from two frames being written simultaneously, would I?

Now, what happens when the overlap is 4? Surely in order to keep up either values from fftin~ are output faster than the audio rate or multiple instances of the subpatch are running concurrently (or I’m very confused!).

I would love for someone to shed light on this for me.