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 34/* Autocorrelations for a warped frequency axis */ 35void silk_warped_autocorrelation_FLP( 36 silk_float *corr, /* O Result [order + 1] */ 37 const silk_float *input, /* I Input data to correlate */ 38 const silk_float warping, /* I Warping coefficient */ 39 const opus_int length, /* I Length of input */ 40 const opus_int order /* I Correlation order (even) */ 41) 42{ 43 opus_int n, i; 44 double tmp1, tmp2; 45 double state[ MAX_SHAPE_LPC_ORDER + 1 ] = { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 }; 46 double C[ MAX_SHAPE_LPC_ORDER + 1 ] = { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 }; 47 48 /* Order must be even */ 49 silk_assert( ( order & 1 ) == 0 ); 50 51 /* Loop over samples */ 52 for( n = 0; n < length; n++ ) { 53 tmp1 = input[ n ]; 54 /* Loop over allpass sections */ 55 for( i = 0; i < order; i += 2 ) { 56 /* Output of allpass section */ 57 tmp2 = state[ i ] + warping * ( state[ i + 1 ] - tmp1 ); 58 state[ i ] = tmp1; 59 C[ i ] += state[ 0 ] * tmp1; 60 /* Output of allpass section */ 61 tmp1 = state[ i + 1 ] + warping * ( state[ i + 2 ] - tmp2 ); 62 state[ i + 1 ] = tmp2; 63 C[ i + 1 ] += state[ 0 ] * tmp2; 64 } 65 state[ order ] = tmp1; 66 C[ order ] += state[ 0 ] * tmp1; 67 } 68 69 /* Copy correlations in silk_float output format */ 70 for( i = 0; i < order + 1; i++ ) { 71 corr[ i ] = ( silk_float )C[ i ]; 72 } 73} 74