Hi all-
I haven't looked at Cyrille's interpolator but... tabread4~ uses true cubic interpolation (which perhaps Cyrille's object also does in some other way). The tabread4~ algorithm is to put a cubic through the 4 points surrounding the input point. However, this cubic curve does not necessarily match the next curve over in first derivative.
A workaround is to up-sample everybody by a factor of 2 - this dramatically reduces error, usually by 24 dB.
All described in chapter 2 of my book, http://crca.ucsd.edu/~msp/techniques.htm
cheers Miller
On Mon, Mar 29, 2010 at 02:29:30PM +0200, Matteo Sisti Sette wrote:
Roman Haefeli escribi??:
Check this thread: http://lists.puredata.info/pipermail/pd-list/2008-06/062878.html
I checked it out (not read the _whole_ thread to the end) but, In what way can the current tabread4~ interpolation, which is discontinuous even in its 1st derivative, be superior to true cubic interpolation? Even at transpositions near to zero, I can't see what's the advantage, nor what it is supposed to minimize.
-- Matteo Sisti Sette matteosistisette@gmail.com http://www.matteosistisette.com
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