[PD] Max Smoother Audio than Pd?

[Claude Heiland-Allen]

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 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?


Claude
-- 
http://claudiusmaximus.goto10.org