Claude Heiland-Allen a écrit :
cyrille henry wrote:
Claude Heiland-Allen a écrit :
Alexandre Porres wrote:
"I feel Max produce a smoother audio than Pd. Didit"
Well, if you use [tabread4~] or any of the many other Pd objects that
use the same broken interpolation algorithm (copy/paste programming),
you get horrible noise. If you use [tabread4] to interpolate
graphical parameters for animations, the discontinuities in the
derivatives are really obvious.
See attached patch - it would be interesting to see if a Max/MSP port
of this patch exhibits the same problem.
well, the cos~ object does not internally use a 4 points interpolation.
see code : *out++ = f1 + frac * (f2 - f1);
it's a 2 points linear interpolation.
Oops! Sorry for making assumptions and not checking the source :-/
nusmuk audio tabread4c~ uses the correct interpolation algorithm,
correct me if I'm wrong.
i don't think there is a correct interpolation algorythm.
True - it depends on the purpose.
But IMHO if you're doing piecewise cubic interpolation, it's a bit of a
nonsense to have a cubic that goes through all 4 points when it's only
being used between the inner-most 2 points (a new cubic equation is
calculated each time you go past another sample in the table).
i think the interpolation used by miller is the one that minimise the error.
other interpolating methods could have more error, but sound better.
I heard that software like reaktor use very diferent algorythm, with
lot's more points, in order to have a band limited interpolation.
Interesting. Maybe some kind of FFT-based interpolation could be used?
it's more something using sinc to instead of dirac to reconstruct the signal.
http://en.wikipedia.org/wiki/Sinc
Cyrille
Claude
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