[Clam-devel] streaming SDIF files

Xavier Amatriain xavier at create.ucsb.edu
Fri Jun 29 04:46:33 PDT 2007


Hi Greg,

> I've been having a problem with artifacts though that seem to be 
> coming from the overlapping of windows.  My guess is that either a 
> triangular window is not being applied to the audio windows before 
> they are being overlapped or that the step-size is not correct.  
I am almost sure that your problem is with the hop/size. If you use 
SMSSynthesis it is very unlikely that the triangular window is not applied.
> But even though I've played around with a lot of different parameter 
> values, I can't seem to make the problem go away.  Can someone tell me 
> where exactly this overlap-adding is supposed to be taking place?  
> Which class is responsible for it?
The OverlapAdd takes place in the SMSSynthesis class lines 260 and 268:

http://www.clam.iua.upf.edu/doc/CLAM-devel-doxygen/SMSSynthesis_8cxx-source.html#l00200;

And the class responsible for it is the OverlapAdd class

http://www.clam.iua.upf.edu/doc/CLAM-devel-doxygen/classCLAM_1_1OverlapAdd.html

A rule of thumb: synthesis hopsize and framesize should both be equal to 
analysis hopsize. (Synthesis hopsize defines how much the
triangular window advances and framesize is half of the triangular 
window size. Note that neither of them have anything to do with the
analysis window size).

Hope it helps.




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