voice-gateway/third_party/speex/libspeex/lpc.h

/* Copyright (C) 2002 Jean-Marc Valin */
/**
   @file lpc.h
   @brief Functions for LPC (Linear Prediction Coefficients) analysis
*/
/*
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   are met:
   
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   notice, this list of conditions and the following disclaimer in the
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   this software without specific prior written permission.
   
   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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*/

#ifndef LPC_H
#define LPC_H

#include "arch.h"

void _spx_autocorr(
              const spx_word16_t * x,   /*  in: [0...n-1] samples x   */
              spx_word16_t *ac,   /* out: [0...lag-1] ac values */
              int lag, int   n);

spx_word32_t                      /* returns minimum mean square error    */
_spx_lpc(
    spx_coef_t       * lpc, /*      [0...p-1] LPC coefficients      */
    const spx_word16_t * ac,  /*  in: [0...p] autocorrelation values  */
    int p
    );


#endif