helpfun.h

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 /******************************************************************

 iLBC Speech Coder ANSI-C Source Code

 helpfun.h

 Copyright (C) The Internet Society (2004).
 All Rights Reserved.

 ******************************************************************/

 #ifndef __iLBC_HELPFUN_H
 #define __iLBC_HELPFUN_H

 void autocorr(
 float *r, /* (o) autocorrelation vector */
 const float *x, /* (i) data vector */
 int N, /* (i) length of data vector */
 int order /* largest lag for calculated
 autocorrelations */
 );

 void window(
 float *z, /* (o) the windowed data */
 const float *x, /* (i) the original data vector */
 const float *y, /* (i) the window */
 int N /* (i) length of all vectors */
 );

 void levdurb(
 float *a, /* (o) lpc coefficient vector starting
 with 1.0 */
 float *k, /* (o) reflection coefficients */
 float *r, /* (i) autocorrelation vector */
 int order /* (i) order of lpc filter */
 );

 void interpolate(





 float *out, /* (o) the interpolated vector */
 float *in1, /* (i) the first vector for the
 interpolation */
 float *in2, /* (i) the second vector for the
 interpolation */
 float coef, /* (i) interpolation weights */
 int length /* (i) length of all vectors */
 );

 void bwexpand(
 float *out, /* (o) the bandwidth expanded lpc
 coefficients */
 float *in, /* (i) the lpc coefficients before bandwidth
 expansion */
 float coef, /* (i) the bandwidth expansion factor */
 int length /* (i) the length of lpc coefficient vectors */
 );

 void vq(
 float *Xq, /* (o) the quantized vector */
 int *index, /* (o) the quantization index */
 const float *CB,/* (i) the vector quantization codebook */
 float *X, /* (i) the vector to quantize */
 int n_cb, /* (i) the number of vectors in the codebook */
 int dim /* (i) the dimension of all vectors */
 );

 void SplitVQ(
 float *qX, /* (o) the quantized vector */
 int *index, /* (o) a vector of indexes for all vector
 codebooks in the split */
 float *X, /* (i) the vector to quantize */
 const float *CB,/* (i) the quantizer codebook */
 int nsplit, /* the number of vector splits */
 const int *dim, /* the dimension of X and qX */
 const int *cbsize /* the number of vectors in the codebook */
 );


 void sort_sq(
 float *xq, /* (o) the quantized value */
 int *index, /* (o) the quantization index */
 float x, /* (i) the value to quantize */
 const float *cb,/* (i) the quantization codebook */
 int cb_size /* (i) the size of the quantization codebook */
 );

 int LSF_check( /* (o) 1 for stable lsf vectors and 0 for





 nonstable ones */
 float *lsf, /* (i) a table of lsf vectors */
 int dim, /* (i) the dimension of each lsf vector */
 int NoAn /* (i) the number of lsf vectors in the
 table */
 );

 #endif