1/*********************************************************************** 2Copyright (c) 2006-2011, Skype Limited. All rights reserved. 3Redistribution and use in source and binary forms, with or without 4modification, are permitted provided that the following conditions 5are met: 6- Redistributions of source code must retain the above copyright notice, 7this list of conditions and the following disclaimer. 8- Redistributions in binary form must reproduce the above copyright 9notice, this list of conditions and the following disclaimer in the 10documentation and/or other materials provided with the distribution. 11- Neither the name of Internet Society, IETF or IETF Trust, nor the 12names of specific contributors, may be used to endorse or promote 13products derived from this software without specific prior written 14permission. 15THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 16AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 19LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 20CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 21SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 22INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 23CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 24ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 25POSSIBILITY OF SUCH DAMAGE. 26***********************************************************************/ 27 28#ifdef HAVE_CONFIG_H 29#include "config.h" 30#endif 31 32#include "main_FLP.h" 33 34void silk_LTP_analysis_filter_FLP( 35 silk_float *LTP_res, /* O LTP res MAX_NB_SUBFR*(pre_lgth+subfr_lngth) */ 36 const silk_float *x, /* I Input signal, with preceding samples */ 37 const silk_float B[ LTP_ORDER * MAX_NB_SUBFR ], /* I LTP coefficients for each subframe */ 38 const opus_int pitchL[ MAX_NB_SUBFR ], /* I Pitch lags */ 39 const silk_float invGains[ MAX_NB_SUBFR ], /* I Inverse quantization gains */ 40 const opus_int subfr_length, /* I Length of each subframe */ 41 const opus_int nb_subfr, /* I number of subframes */ 42 const opus_int pre_length /* I Preceding samples for each subframe */ 43) 44{ 45 const silk_float *x_ptr, *x_lag_ptr; 46 silk_float Btmp[ LTP_ORDER ]; 47 silk_float *LTP_res_ptr; 48 silk_float inv_gain; 49 opus_int k, i, j; 50 51 x_ptr = x; 52 LTP_res_ptr = LTP_res; 53 for( k = 0; k < nb_subfr; k++ ) { 54 x_lag_ptr = x_ptr - pitchL[ k ]; 55 inv_gain = invGains[ k ]; 56 for( i = 0; i < LTP_ORDER; i++ ) { 57 Btmp[ i ] = B[ k * LTP_ORDER + i ]; 58 } 59 60 /* LTP analysis FIR filter */ 61 for( i = 0; i < subfr_length + pre_length; i++ ) { 62 LTP_res_ptr[ i ] = x_ptr[ i ]; 63 /* Subtract long-term prediction */ 64 for( j = 0; j < LTP_ORDER; j++ ) { 65 LTP_res_ptr[ i ] -= Btmp[ j ] * x_lag_ptr[ LTP_ORDER / 2 - j ]; 66 } 67 LTP_res_ptr[ i ] *= inv_gain; 68 x_lag_ptr++; 69 } 70 71 /* Update pointers */ 72 LTP_res_ptr += subfr_length + pre_length; 73 x_ptr += subfr_length; 74 } 75} 76