ref: d6a0216cf1ed5e5fdb9c390f8857afee5f153146
dir: /silk/silk_burg_modified.c/
/*********************************************************************** Copyright (c) 2006-2011, Skype Limited. All rights reserved. Redistribution and use in source and binary forms, with or without modification, (subject to the limitations in the disclaimer below) 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 Skype Limited, nor the names of specific contributors, may be used to endorse or promote products derived from this software without specific prior written permission. NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED BY THIS LICENSE. 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 COPYRIGHT OWNER 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. ***********************************************************************/ #include "silk_SigProc_FIX.h" #define MAX_FRAME_SIZE 384 // subfr_length * nb_subfr = ( 0.005 * 16000 + 16 ) * 4 = 384 #define MAX_NB_SUBFR 4 #define QA 25 #define N_BITS_HEAD_ROOM 2 #define MIN_RSHIFTS -16 #define MAX_RSHIFTS (32 - QA) /* Compute reflection coefficients from input signal */ void silk_burg_modified( opus_int32 *res_nrg, /* O residual energy */ opus_int *res_nrg_Q, /* O residual energy Q value */ opus_int32 A_Q16[], /* O prediction coefficients (length order) */ const opus_int16 x[], /* I input signal, length: nb_subfr * ( D + subfr_length ) */ const opus_int subfr_length, /* I input signal subframe length (including D preceeding samples) */ const opus_int nb_subfr, /* I number of subframes stacked in x */ const opus_int32 WhiteNoiseFrac_Q32, /* I fraction added to zero-lag autocorrelation */ const opus_int D /* I order */ ) { opus_int k, n, s, lz, rshifts, rshifts_extra; opus_int32 C0, num, nrg, rc_Q31, Atmp_QA, Atmp1, tmp1, tmp2, x1, x2; const opus_int16 *x_ptr; opus_int32 C_first_row[ SILK_MAX_ORDER_LPC ]; opus_int32 C_last_row[ SILK_MAX_ORDER_LPC ]; opus_int32 Af_QA[ SILK_MAX_ORDER_LPC ]; opus_int32 CAf[ SILK_MAX_ORDER_LPC + 1 ]; opus_int32 CAb[ SILK_MAX_ORDER_LPC + 1 ]; SKP_assert( subfr_length * nb_subfr <= MAX_FRAME_SIZE ); SKP_assert( nb_subfr <= MAX_NB_SUBFR ); /* Compute autocorrelations, added over subframes */ silk_sum_sqr_shift( &C0, &rshifts, x, nb_subfr * subfr_length ); if( rshifts > MAX_RSHIFTS ) { C0 = SKP_LSHIFT32( C0, rshifts - MAX_RSHIFTS ); SKP_assert( C0 > 0 ); rshifts = MAX_RSHIFTS; } else { lz = silk_CLZ32( C0 ) - 1; rshifts_extra = N_BITS_HEAD_ROOM - lz; if( rshifts_extra > 0 ) { rshifts_extra = SKP_min( rshifts_extra, MAX_RSHIFTS - rshifts ); C0 = SKP_RSHIFT32( C0, rshifts_extra ); } else { rshifts_extra = SKP_max( rshifts_extra, MIN_RSHIFTS - rshifts ); C0 = SKP_LSHIFT32( C0, -rshifts_extra ); } rshifts += rshifts_extra; } SKP_memset( C_first_row, 0, SILK_MAX_ORDER_LPC * sizeof( opus_int32 ) ); if( rshifts > 0 ) { for( s = 0; s < nb_subfr; s++ ) { x_ptr = x + s * subfr_length; for( n = 1; n < D + 1; n++ ) { C_first_row[ n - 1 ] += (opus_int32)SKP_RSHIFT64( silk_inner_prod16_aligned_64( x_ptr, x_ptr + n, subfr_length - n ), rshifts ); } } } else { for( s = 0; s < nb_subfr; s++ ) { x_ptr = x + s * subfr_length; for( n = 1; n < D + 1; n++ ) { C_first_row[ n - 1 ] += SKP_LSHIFT32( silk_inner_prod_aligned( x_ptr, x_ptr + n, subfr_length - n ), -rshifts ); } } } SKP_memcpy( C_last_row, C_first_row, SILK_MAX_ORDER_LPC * sizeof( opus_int32 ) ); /* Initialize */ CAb[ 0 ] = CAf[ 0 ] = C0 + SKP_SMMUL( WhiteNoiseFrac_Q32, C0 ) + 1; // Q(-rshifts) for( n = 0; n < D; n++ ) { /* Update first row of correlation matrix (without first element) */ /* Update last row of correlation matrix (without last element, stored in reversed order) */ /* Update C * Af */ /* Update C * flipud(Af) (stored in reversed order) */ if( rshifts > -2 ) { for( s = 0; s < nb_subfr; s++ ) { x_ptr = x + s * subfr_length; x1 = -SKP_LSHIFT32( (opus_int32)x_ptr[ n ], 16 - rshifts ); // Q(16-rshifts) x2 = -SKP_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], 16 - rshifts ); // Q(16-rshifts) tmp1 = SKP_LSHIFT32( (opus_int32)x_ptr[ n ], QA - 16 ); // Q(QA-16) tmp2 = SKP_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], QA - 16 ); // Q(QA-16) for( k = 0; k < n; k++ ) { C_first_row[ k ] = SKP_SMLAWB( C_first_row[ k ], x1, x_ptr[ n - k - 1 ] ); // Q( -rshifts ) C_last_row[ k ] = SKP_SMLAWB( C_last_row[ k ], x2, x_ptr[ subfr_length - n + k ] ); // Q( -rshifts ) Atmp_QA = Af_QA[ k ]; tmp1 = SKP_SMLAWB( tmp1, Atmp_QA, x_ptr[ n - k - 1 ] ); // Q(QA-16) tmp2 = SKP_SMLAWB( tmp2, Atmp_QA, x_ptr[ subfr_length - n + k ] ); // Q(QA-16) } tmp1 = SKP_LSHIFT32( -tmp1, 32 - QA - rshifts ); // Q(16-rshifts) tmp2 = SKP_LSHIFT32( -tmp2, 32 - QA - rshifts ); // Q(16-rshifts) for( k = 0; k <= n; k++ ) { CAf[ k ] = SKP_SMLAWB( CAf[ k ], tmp1, x_ptr[ n - k ] ); // Q( -rshift ) CAb[ k ] = SKP_SMLAWB( CAb[ k ], tmp2, x_ptr[ subfr_length - n + k - 1 ] ); // Q( -rshift ) } } } else { for( s = 0; s < nb_subfr; s++ ) { x_ptr = x + s * subfr_length; x1 = -SKP_LSHIFT32( (opus_int32)x_ptr[ n ], -rshifts ); // Q( -rshifts ) x2 = -SKP_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], -rshifts ); // Q( -rshifts ) tmp1 = SKP_LSHIFT32( (opus_int32)x_ptr[ n ], 17 ); // Q17 tmp2 = SKP_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], 17 ); // Q17 for( k = 0; k < n; k++ ) { C_first_row[ k ] = SKP_MLA( C_first_row[ k ], x1, x_ptr[ n - k - 1 ] ); // Q( -rshifts ) C_last_row[ k ] = SKP_MLA( C_last_row[ k ], x2, x_ptr[ subfr_length - n + k ] ); // Q( -rshifts ) Atmp1 = SKP_RSHIFT_ROUND( Af_QA[ k ], QA - 17 ); // Q17 tmp1 = SKP_MLA( tmp1, x_ptr[ n - k - 1 ], Atmp1 ); // Q17 tmp2 = SKP_MLA( tmp2, x_ptr[ subfr_length - n + k ], Atmp1 ); // Q17 } tmp1 = -tmp1; // Q17 tmp2 = -tmp2; // Q17 for( k = 0; k <= n; k++ ) { CAf[ k ] = SKP_SMLAWW( CAf[ k ], tmp1, SKP_LSHIFT32( (opus_int32)x_ptr[ n - k ], -rshifts - 1 ) ); // Q( -rshift ) CAb[ k ] = SKP_SMLAWW( CAb[ k ], tmp2, SKP_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n + k - 1 ], -rshifts - 1 ) );// Q( -rshift ) } } } /* Calculate nominator and denominator for the next order reflection (parcor) coefficient */ tmp1 = C_first_row[ n ]; // Q( -rshifts ) tmp2 = C_last_row[ n ]; // Q( -rshifts ) num = 0; // Q( -rshifts ) nrg = SKP_ADD32( CAb[ 0 ], CAf[ 0 ] ); // Q( 1-rshifts ) for( k = 0; k < n; k++ ) { Atmp_QA = Af_QA[ k ]; lz = silk_CLZ32( SKP_abs( Atmp_QA ) ) - 1; lz = SKP_min( 32 - QA, lz ); Atmp1 = SKP_LSHIFT32( Atmp_QA, lz ); // Q( QA + lz ) tmp1 = SKP_ADD_LSHIFT32( tmp1, SKP_SMMUL( C_last_row[ n - k - 1 ], Atmp1 ), 32 - QA - lz ); // Q( -rshifts ) tmp2 = SKP_ADD_LSHIFT32( tmp2, SKP_SMMUL( C_first_row[ n - k - 1 ], Atmp1 ), 32 - QA - lz ); // Q( -rshifts ) num = SKP_ADD_LSHIFT32( num, SKP_SMMUL( CAb[ n - k ], Atmp1 ), 32 - QA - lz ); // Q( -rshifts ) nrg = SKP_ADD_LSHIFT32( nrg, SKP_SMMUL( SKP_ADD32( CAb[ k + 1 ], CAf[ k + 1 ] ), Atmp1 ), 32 - QA - lz ); // Q( 1-rshifts ) } CAf[ n + 1 ] = tmp1; // Q( -rshifts ) CAb[ n + 1 ] = tmp2; // Q( -rshifts ) num = SKP_ADD32( num, tmp2 ); // Q( -rshifts ) num = SKP_LSHIFT32( -num, 1 ); // Q( 1-rshifts ) /* Calculate the next order reflection (parcor) coefficient */ if( SKP_abs( num ) < nrg ) { rc_Q31 = silk_DIV32_varQ( num, nrg, 31 ); } else { /* Negative energy or ratio too high; set remaining coefficients to zero and exit loop */ SKP_memset( &Af_QA[ n ], 0, ( D - n ) * sizeof( opus_int32 ) ); SKP_assert( 0 ); break; } /* Update the AR coefficients */ for( k = 0; k < (n + 1) >> 1; k++ ) { tmp1 = Af_QA[ k ]; // QA tmp2 = Af_QA[ n - k - 1 ]; // QA Af_QA[ k ] = SKP_ADD_LSHIFT32( tmp1, SKP_SMMUL( tmp2, rc_Q31 ), 1 ); // QA Af_QA[ n - k - 1 ] = SKP_ADD_LSHIFT32( tmp2, SKP_SMMUL( tmp1, rc_Q31 ), 1 ); // QA } Af_QA[ n ] = SKP_RSHIFT32( rc_Q31, 31 - QA ); // QA /* Update C * Af and C * Ab */ for( k = 0; k <= n + 1; k++ ) { tmp1 = CAf[ k ]; // Q( -rshifts ) tmp2 = CAb[ n - k + 1 ]; // Q( -rshifts ) CAf[ k ] = SKP_ADD_LSHIFT32( tmp1, SKP_SMMUL( tmp2, rc_Q31 ), 1 ); // Q( -rshifts ) CAb[ n - k + 1 ] = SKP_ADD_LSHIFT32( tmp2, SKP_SMMUL( tmp1, rc_Q31 ), 1 ); // Q( -rshifts ) } } /* Return residual energy */ nrg = CAf[ 0 ]; // Q( -rshifts ) tmp1 = 1 << 16; // Q16 for( k = 0; k < D; k++ ) { Atmp1 = SKP_RSHIFT_ROUND( Af_QA[ k ], QA - 16 ); // Q16 nrg = SKP_SMLAWW( nrg, CAf[ k + 1 ], Atmp1 ); // Q( -rshifts ) tmp1 = SKP_SMLAWW( tmp1, Atmp1, Atmp1 ); // Q16 A_Q16[ k ] = -Atmp1; } *res_nrg = SKP_SMLAWW( nrg, SKP_SMMUL( WhiteNoiseFrac_Q32, C0 ), -tmp1 ); // Q( -rshifts ) *res_nrg_Q = -rshifts; }