thanks master well, I was betting it was that, and it actually brings me to more direct questions I should have asked before. So here they go.
Simply put: How come and why does overlapping affect the sample rate? > the same happens if you raise the "samplerate" via "upsampling". I guess this is what's really confusing, cause I can't seem to get it. If you do upsampling with block, for instance, you don't get this frequency change issue with [osc~]. It'll run the same frequency, no problem... but overlapping will do that somehow. Why the hell the actual upsampling does not affect it? And does this mean that overlap of 4 and upsampling of 4x makes it really run at 16x the sample rate? cheers 2013/11/26 IOhannes m zmölnig <zmoel...@iem.at> > On 2013-11-26 11:19, Alexandre Torres Porres wrote: > > Howdy, ever tried to compute a hann window inside a subpatch where the > FFT > > is happening? > > > > And then if you're overlapping it by 4, do you see that only 1/4 of the > > cycle from [osc~] came up? > > > > That means the [osc~] frequency was 1/4 what it should be... > > > > Now, why and how does it happen? I just have no clue at all. > > > > that is mainly because the "sample rate" within the overlapped canvas is > higher than the sample rate outside. > (e.g. if you are doing an overlap of 2, you are in fact processing the > double amount of data in the same time, so your overlapping "sample > rate" is 88200 if the non-overlapping rate is 44100). > the same happens if you raise the "samplerate" via "upsampling". > > > [osc~] uses the sample-rate information (within the signal data > structure) to calculate the phase of a cosine-table lookup. > > btw, there has been a long-standing feature request [1] to extend the > signal-structure to hold both overlap factor and sample-rate, so > signal-processing objects could handle upsampling and overlapping > differently. > (speaking of which, it would also be nice, if any dsp object could have > a notion of the current overlap cycle) > > > gfmasr > IOhannes > > > [1] https://sourceforge.net/p/pure-data/feature-requests/16/ > > > _______________________________________________ > Pd-list@iem.at mailing list > UNSUBSCRIBE and account-management -> > http://lists.puredata.info/listinfo/pd-list > >
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