12bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian/*********************************************************************** 22bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh VenkatasubramanianCopyright (c) 2006-2011, Skype Limited. All rights reserved. 32bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh VenkatasubramanianRedistribution and use in source and binary forms, with or without 42bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanianmodification, are permitted provided that the following conditions 52bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanianare met: 62bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian- Redistributions of source code must retain the above copyright notice, 72bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanianthis list of conditions and the following disclaimer. 82bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian- Redistributions in binary form must reproduce the above copyright 92bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramaniannotice, this list of conditions and the following disclaimer in the 102bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramaniandocumentation and/or other materials provided with the distribution. 112bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian- Neither the name of Internet Society, IETF or IETF Trust, nor the 122bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramaniannames of specific contributors, may be used to endorse or promote 132bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanianproducts derived from this software without specific prior written 142bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanianpermission. 152bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh VenkatasubramanianTHIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 162bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh VenkatasubramanianAND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 172bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh VenkatasubramanianIMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 182bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh VenkatasubramanianARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 192bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh VenkatasubramanianLIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 202bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh VenkatasubramanianCONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 212bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh VenkatasubramanianSUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 222bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh VenkatasubramanianINTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 232bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh VenkatasubramanianCONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 242bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh VenkatasubramanianARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 252bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh VenkatasubramanianPOSSIBILITY OF SUCH DAMAGE. 262bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian***********************************************************************/ 272bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian 282bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian#ifdef HAVE_CONFIG_H 292bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian#include "config.h" 302bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian#endif 312bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian 322bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian/* 332bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian Elliptic/Cauer filters designed with 0.1 dB passband ripple, 342bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian 80 dB minimum stopband attenuation, and 352bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian [0.95 : 0.15 : 0.35] normalized cut off frequencies. 362bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian*/ 372bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian 382bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian#include "main.h" 392bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian 402bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian/* Helper function, interpolates the filter taps */ 412bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanianstatic OPUS_INLINE void silk_LP_interpolate_filter_taps( 422bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian opus_int32 B_Q28[ TRANSITION_NB ], 432bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian opus_int32 A_Q28[ TRANSITION_NA ], 442bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian const opus_int ind, 452bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian const opus_int32 fac_Q16 462bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian) 472bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian{ 482bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian opus_int nb, na; 492bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian 502bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian if( ind < TRANSITION_INT_NUM - 1 ) { 512bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian if( fac_Q16 > 0 ) { 522bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian if( fac_Q16 < 32768 ) { /* fac_Q16 is in range of a 16-bit int */ 532bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian /* Piece-wise linear interpolation of B and A */ 542bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian for( nb = 0; nb < TRANSITION_NB; nb++ ) { 552bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian B_Q28[ nb ] = silk_SMLAWB( 562bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_Transition_LP_B_Q28[ ind ][ nb ], 572bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_Transition_LP_B_Q28[ ind + 1 ][ nb ] - 582bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_Transition_LP_B_Q28[ ind ][ nb ], 592bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian fac_Q16 ); 602bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian } 612bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian for( na = 0; na < TRANSITION_NA; na++ ) { 622bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian A_Q28[ na ] = silk_SMLAWB( 632bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_Transition_LP_A_Q28[ ind ][ na ], 642bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_Transition_LP_A_Q28[ ind + 1 ][ na ] - 652bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_Transition_LP_A_Q28[ ind ][ na ], 662bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian fac_Q16 ); 672bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian } 682bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian } else { /* ( fac_Q16 - ( 1 << 16 ) ) is in range of a 16-bit int */ 692bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_assert( fac_Q16 - ( 1 << 16 ) == silk_SAT16( fac_Q16 - ( 1 << 16 ) ) ); 702bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian /* Piece-wise linear interpolation of B and A */ 712bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian for( nb = 0; nb < TRANSITION_NB; nb++ ) { 722bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian B_Q28[ nb ] = silk_SMLAWB( 732bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_Transition_LP_B_Q28[ ind + 1 ][ nb ], 742bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_Transition_LP_B_Q28[ ind + 1 ][ nb ] - 752bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_Transition_LP_B_Q28[ ind ][ nb ], 762bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian fac_Q16 - ( (opus_int32)1 << 16 ) ); 772bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian } 782bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian for( na = 0; na < TRANSITION_NA; na++ ) { 792bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian A_Q28[ na ] = silk_SMLAWB( 802bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_Transition_LP_A_Q28[ ind + 1 ][ na ], 812bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_Transition_LP_A_Q28[ ind + 1 ][ na ] - 822bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_Transition_LP_A_Q28[ ind ][ na ], 832bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian fac_Q16 - ( (opus_int32)1 << 16 ) ); 842bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian } 852bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian } 862bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian } else { 872bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_memcpy( B_Q28, silk_Transition_LP_B_Q28[ ind ], TRANSITION_NB * sizeof( opus_int32 ) ); 882bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_memcpy( A_Q28, silk_Transition_LP_A_Q28[ ind ], TRANSITION_NA * sizeof( opus_int32 ) ); 892bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian } 902bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian } else { 912bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_memcpy( B_Q28, silk_Transition_LP_B_Q28[ TRANSITION_INT_NUM - 1 ], TRANSITION_NB * sizeof( opus_int32 ) ); 922bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_memcpy( A_Q28, silk_Transition_LP_A_Q28[ TRANSITION_INT_NUM - 1 ], TRANSITION_NA * sizeof( opus_int32 ) ); 932bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian } 942bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian} 952bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian 962bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian/* Low-pass filter with variable cutoff frequency based on */ 972bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian/* piece-wise linear interpolation between elliptic filters */ 982bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian/* Start by setting psEncC->mode <> 0; */ 992bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian/* Deactivate by setting psEncC->mode = 0; */ 1002bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanianvoid silk_LP_variable_cutoff( 1012bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_LP_state *psLP, /* I/O LP filter state */ 1022bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian opus_int16 *frame, /* I/O Low-pass filtered output signal */ 1032bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian const opus_int frame_length /* I Frame length */ 1042bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian) 1052bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian{ 1062bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian opus_int32 B_Q28[ TRANSITION_NB ], A_Q28[ TRANSITION_NA ], fac_Q16 = 0; 1072bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian opus_int ind = 0; 1082bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian 1092bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_assert( psLP->transition_frame_no >= 0 && psLP->transition_frame_no <= TRANSITION_FRAMES ); 1102bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian 1112bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian /* Run filter if needed */ 1122bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian if( psLP->mode != 0 ) { 1132bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian /* Calculate index and interpolation factor for interpolation */ 1142bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian#if( TRANSITION_INT_STEPS == 64 ) 1152bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian fac_Q16 = silk_LSHIFT( TRANSITION_FRAMES - psLP->transition_frame_no, 16 - 6 ); 1162bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian#else 1172bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian fac_Q16 = silk_DIV32_16( silk_LSHIFT( TRANSITION_FRAMES - psLP->transition_frame_no, 16 ), TRANSITION_FRAMES ); 1182bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian#endif 1192bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian ind = silk_RSHIFT( fac_Q16, 16 ); 1202bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian fac_Q16 -= silk_LSHIFT( ind, 16 ); 1212bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian 1222bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_assert( ind >= 0 ); 1232bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_assert( ind < TRANSITION_INT_NUM ); 1242bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian 1252bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian /* Interpolate filter coefficients */ 1262bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_LP_interpolate_filter_taps( B_Q28, A_Q28, ind, fac_Q16 ); 1272bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian 1282bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian /* Update transition frame number for next frame */ 1292bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian psLP->transition_frame_no = silk_LIMIT( psLP->transition_frame_no + psLP->mode, 0, TRANSITION_FRAMES ); 1302bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian 1312bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian /* ARMA low-pass filtering */ 1322bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_assert( TRANSITION_NB == 3 && TRANSITION_NA == 2 ); 1332bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian silk_biquad_alt( frame, B_Q28, A_Q28, psLP->In_LP_State, frame, frame_length, 1); 1342bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian } 1352bd8b54017b5320bc0c1df9bf86f4cdc9f8db242Vignesh Venkatasubramanian} 136