[PD] OT: Windowing

[pix]

assuming that you are treating the sum-to-unity criteria as sacred, my
first smart-ass suggestion would be:

an envelope that changes size to ensure the overlap is always 50% (or some
known value, depending on the actual shape of the envelope)

... ;)

i'm not sure if there is a non-smart-ass answer.

pix.

On Thu, 3 Jul 2003 17:24:31 +0100
"matthew jones" <M.Jones at signal.qinetiq.com> wrote:

> Hi,
> quick OT question for any of the granular synthesis brains out there...
> I want to reconstruct a signal from multiple overlapped segments.  To
> use an overlapp-add method that perfectly reconstructs the original
> waveform I would need to window the segments... now thats fine as long
> as the overlap amount is less than 50 percent.  I can use a Hanning
> window on the overlapping parts and sum them..... Hanning windows
> satisfy the sum to unity criterion.  however, when the overlap is more
> than 50%, the half-Hanning windows applied to the start and end of the
> segments windows begin to overlap.... see this link:
> http://www.loopit.org/images/overlap.jpg
> 
> Now multiplying the overlapped half-Hanning windows together creates a
> new window function for the segments that suddenly does not satisfy the
> 'sum-to-unity' criterion....
> The question is (if anybody can is at all interested):- WHAT window
> function should be used given ANY arbitrary overlap amount???
> 
> Any answers would really help me, though I'd be surprised if this gets a
> response.... ;)
> sorry 2 b so off topic, though for me it's pd related anyway(!). cheers
> 
> matt
> 
> -=-=-=-=-=-=-=-=-=-=-=-=-
> http://www.loopit.org/
> -=-=-=-=-=-=-=-=-=-=-=-=-
> 
> 
> _______________________________________________
> PD-list mailing list
> PD-list at iem.at
> http://iem.at/cgi-bin/mailman/listinfo/pd-list


--