musicdsp.org source code archive - WSInf

16-Point Fast Integer Sinc Interpolator. (click this to go back to the index)
References : Posted by mumart[at]gmail[dot]com
Notes :
This is designed for fast upsampling with good quality using only a 32-bit accumulator. Sound quality is very good. Conceptually it resamples the input
signal 32768x and performs nearest-neighbour to get the requested sample rate. As a result downsampling will result in aliasing.
The provided Sinc table is Blackman-Harris windowed with a slight lowpass. The table entries are 16-bit and are 16x linear-oversampled. It should be
pretty easy to figure out how to make your own table for it.
Code provided is in Java. Converting to C/MMX etc. should be pretty trivial.
Remember the interpolator requires a number of samples before and after the sample to be interpolated, so you can't resample the whole of a passed
input buffer in one go.
Have fun,
Martin
Code :
public class SincResampler {
private final int FP_SHIFT = 15;
private final int FP_ONE = 1