1/* Copyright (C) 2002 Jean-Marc Valin */
2/**
3   @file lpc.h
4   @brief Functions for LPC (Linear Prediction Coefficients) analysis
5*/
6/*
7   Redistribution and use in source and binary forms, with or without
8   modification, are permitted provided that the following conditions
9   are met:
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14   - Redistributions in binary form must reproduce the above copyright
15   notice, this list of conditions and the following disclaimer in the
16   documentation and/or other materials provided with the distribution.
17
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20   this software without specific prior written permission.
21
22   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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33*/
34
35#ifndef LPC_H
36#define LPC_H
37
38#include "arch.h"
39
40void _spx_autocorr(
41              const spx_word16_t * x,   /*  in: [0...n-1] samples x   */
42              spx_word16_t *ac,   /* out: [0...lag-1] ac values */
43              int lag, int   n);
44
45spx_word32_t                      /* returns minimum mean square error    */
46_spx_lpc(
47    spx_coef_t       * lpc, /*      [0...p-1] LPC coefficients      */
48    const spx_word16_t * ac,  /*  in: [0...p] autocorrelation values  */
49    int p
50    );
51
52
53#endif
54