| /* Copyright (C) 2002 Jean-Marc Valin */ |
| /** |
| @file lpc.h |
| @brief Functions for LPC (Linear Prediction Coefficients) analysis |
| */ |
| /* |
| Redistribution and use in source and binary forms, with or without |
| modification, are permitted provided that the following conditions |
| are met: |
| |
| - Redistributions of source code must retain the above copyright |
| notice, this list of conditions and the following disclaimer. |
| |
| - Redistributions in binary form must reproduce the above copyright |
| notice, this list of conditions and the following disclaimer in the |
| documentation and/or other materials provided with the distribution. |
| |
| - Neither the name of the Xiph.org Foundation nor the names of its |
| contributors may be used to endorse or promote products derived from |
| 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 |
| LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR |
| CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #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 |