[PD-dev] [ pure-data-Patches-1509427 ] resampling method for halfblocks

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Patches item #1509427, was opened at 2006-06-20 18:30
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Category: puredata
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: IOhannes m zmölnig (zmoelnig)
Assigned to: Miller Puckette (millerpuckette)
Summary: resampling method for halfblocks

Initial Comment:
this patch adds a new pair of up/downsampling methods,
called "block".

what it does:
 downsampling: the 1st part of the original signal is
copied "as is" to the downsampled signal; the rest of
the incoming signal is discarded
 upsampling: the original signal is copied to the 1st
part of the upsampled signal; the rest of the upsampled
signal is set to 0.f

what for:
 an the output-signals of an fft are redundant since
they are (anti)symmetric; therefore it is a waste of
cpu-power to apply dsp-processing on both halfs of such
signals;
 with this patch it is possible to do a "downsampled"
processing only on the relevant (1st) part of the
signal (~50% performance gain): after upsampling you
would have to recreate the entire signal manually (e.g.
mirror the block and add it to the non-mirrored part)

i also put some defines for the various resampling
methods into m_pd.h, so the code gets less "magic"

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