Alexandre Lision | 8af73cb | 2013-12-10 14:11:20 -0500 | [diff] [blame] | 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: |
| 10 | |
| 11 | - Redistributions of source code must retain the above copyright |
| 12 | notice, this list of conditions and the following disclaimer. |
| 13 | |
| 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 | |
| 18 | - Neither the name of the Xiph.org Foundation nor the names of its |
| 19 | contributors may be used to endorse or promote products derived from |
| 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 |
| 25 | A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR |
| 26 | CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| 27 | EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| 28 | PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| 29 | PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| 30 | LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| 31 | NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| 32 | SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 33 | */ |
| 34 | |
| 35 | #ifndef LPC_H |
| 36 | #define LPC_H |
| 37 | |
| 38 | #include "arch.h" |
| 39 | |
| 40 | void _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 | |
| 45 | spx_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 |