270 lines
16 KiB
C
270 lines
16 KiB
C
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/***********************************************************************
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Copyright (c) 2006-2011, Skype Limited. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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- Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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- Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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- Neither the name of Internet Society, IETF or IETF Trust, nor the
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names of specific contributors, may be used to endorse or promote
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products derived from this software without specific prior written
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permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS”
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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***********************************************************************/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "SigProc_FIX.h"
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#include "define.h"
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#include "tuning_parameters.h"
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#define MAX_FRAME_SIZE 384 /* subfr_length * nb_subfr = ( 0.005 * 16000 + 16 ) * 4 = 384 */
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#define QA 25
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#define N_BITS_HEAD_ROOM 2
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#define MIN_RSHIFTS -16
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#define MAX_RSHIFTS (32 - QA)
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/* Compute reflection coefficients from input signal */
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void silk_burg_modified(
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opus_int32 *res_nrg, /* O Residual energy */
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opus_int *res_nrg_Q, /* O Residual energy Q value */
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opus_int32 A_Q16[], /* O Prediction coefficients (length order) */
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const opus_int16 x[], /* I Input signal, length: nb_subfr * ( D + subfr_length ) */
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const opus_int32 minInvGain_Q30, /* I Inverse of max prediction gain */
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const opus_int subfr_length, /* I Input signal subframe length (incl. D preceding samples) */
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const opus_int nb_subfr, /* I Number of subframes stacked in x */
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const opus_int D /* I Order */
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)
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{
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opus_int k, n, s, lz, rshifts, rshifts_extra, reached_max_gain;
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opus_int32 C0, num, nrg, rc_Q31, invGain_Q30, Atmp_QA, Atmp1, tmp1, tmp2, x1, x2;
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const opus_int16 *x_ptr;
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opus_int32 C_first_row[ SILK_MAX_ORDER_LPC ];
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opus_int32 C_last_row[ SILK_MAX_ORDER_LPC ];
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opus_int32 Af_QA[ SILK_MAX_ORDER_LPC ];
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opus_int32 CAf[ SILK_MAX_ORDER_LPC + 1 ];
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opus_int32 CAb[ SILK_MAX_ORDER_LPC + 1 ];
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silk_assert( subfr_length * nb_subfr <= MAX_FRAME_SIZE );
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/* Compute autocorrelations, added over subframes */
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silk_sum_sqr_shift( &C0, &rshifts, x, nb_subfr * subfr_length );
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if( rshifts > MAX_RSHIFTS ) {
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C0 = silk_LSHIFT32( C0, rshifts - MAX_RSHIFTS );
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silk_assert( C0 > 0 );
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rshifts = MAX_RSHIFTS;
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} else {
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lz = silk_CLZ32( C0 ) - 1;
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rshifts_extra = N_BITS_HEAD_ROOM - lz;
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if( rshifts_extra > 0 ) {
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rshifts_extra = silk_min( rshifts_extra, MAX_RSHIFTS - rshifts );
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C0 = silk_RSHIFT32( C0, rshifts_extra );
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} else {
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rshifts_extra = silk_max( rshifts_extra, MIN_RSHIFTS - rshifts );
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C0 = silk_LSHIFT32( C0, -rshifts_extra );
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}
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rshifts += rshifts_extra;
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}
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CAb[ 0 ] = CAf[ 0 ] = C0 + silk_SMMUL( SILK_FIX_CONST( FIND_LPC_COND_FAC, 32 ), C0 ) + 1; /* Q(-rshifts) */
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silk_memset( C_first_row, 0, SILK_MAX_ORDER_LPC * sizeof( opus_int32 ) );
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if( rshifts > 0 ) {
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for( s = 0; s < nb_subfr; s++ ) {
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x_ptr = x + s * subfr_length;
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for( n = 1; n < D + 1; n++ ) {
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C_first_row[ n - 1 ] += (opus_int32)silk_RSHIFT64(
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silk_inner_prod16_aligned_64( x_ptr, x_ptr + n, subfr_length - n ), rshifts );
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}
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}
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} else {
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for( s = 0; s < nb_subfr; s++ ) {
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x_ptr = x + s * subfr_length;
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for( n = 1; n < D + 1; n++ ) {
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C_first_row[ n - 1 ] += silk_LSHIFT32(
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silk_inner_prod_aligned( x_ptr, x_ptr + n, subfr_length - n ), -rshifts );
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}
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}
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}
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silk_memcpy( C_last_row, C_first_row, SILK_MAX_ORDER_LPC * sizeof( opus_int32 ) );
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/* Initialize */
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CAb[ 0 ] = CAf[ 0 ] = C0 + silk_SMMUL( SILK_FIX_CONST( FIND_LPC_COND_FAC, 32 ), C0 ) + 1; /* Q(-rshifts) */
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invGain_Q30 = (opus_int32)1 << 30;
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reached_max_gain = 0;
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for( n = 0; n < D; n++ ) {
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/* Update first row of correlation matrix (without first element) */
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/* Update last row of correlation matrix (without last element, stored in reversed order) */
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/* Update C * Af */
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/* Update C * flipud(Af) (stored in reversed order) */
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if( rshifts > -2 ) {
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for( s = 0; s < nb_subfr; s++ ) {
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x_ptr = x + s * subfr_length;
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x1 = -silk_LSHIFT32( (opus_int32)x_ptr[ n ], 16 - rshifts ); /* Q(16-rshifts) */
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x2 = -silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], 16 - rshifts ); /* Q(16-rshifts) */
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tmp1 = silk_LSHIFT32( (opus_int32)x_ptr[ n ], QA - 16 ); /* Q(QA-16) */
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tmp2 = silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], QA - 16 ); /* Q(QA-16) */
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for( k = 0; k < n; k++ ) {
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C_first_row[ k ] = silk_SMLAWB( C_first_row[ k ], x1, x_ptr[ n - k - 1 ] ); /* Q( -rshifts ) */
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C_last_row[ k ] = silk_SMLAWB( C_last_row[ k ], x2, x_ptr[ subfr_length - n + k ] ); /* Q( -rshifts ) */
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Atmp_QA = Af_QA[ k ];
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tmp1 = silk_SMLAWB( tmp1, Atmp_QA, x_ptr[ n - k - 1 ] ); /* Q(QA-16) */
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tmp2 = silk_SMLAWB( tmp2, Atmp_QA, x_ptr[ subfr_length - n + k ] ); /* Q(QA-16) */
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}
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tmp1 = silk_LSHIFT32( -tmp1, 32 - QA - rshifts ); /* Q(16-rshifts) */
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tmp2 = silk_LSHIFT32( -tmp2, 32 - QA - rshifts ); /* Q(16-rshifts) */
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for( k = 0; k <= n; k++ ) {
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CAf[ k ] = silk_SMLAWB( CAf[ k ], tmp1, x_ptr[ n - k ] ); /* Q( -rshift ) */
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CAb[ k ] = silk_SMLAWB( CAb[ k ], tmp2, x_ptr[ subfr_length - n + k - 1 ] ); /* Q( -rshift ) */
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}
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}
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} else {
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for( s = 0; s < nb_subfr; s++ ) {
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x_ptr = x + s * subfr_length;
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x1 = -silk_LSHIFT32( (opus_int32)x_ptr[ n ], -rshifts ); /* Q( -rshifts ) */
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x2 = -silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], -rshifts ); /* Q( -rshifts ) */
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tmp1 = silk_LSHIFT32( (opus_int32)x_ptr[ n ], 17 ); /* Q17 */
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tmp2 = silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], 17 ); /* Q17 */
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for( k = 0; k < n; k++ ) {
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C_first_row[ k ] = silk_MLA( C_first_row[ k ], x1, x_ptr[ n - k - 1 ] ); /* Q( -rshifts ) */
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C_last_row[ k ] = silk_MLA( C_last_row[ k ], x2, x_ptr[ subfr_length - n + k ] ); /* Q( -rshifts ) */
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Atmp1 = silk_RSHIFT_ROUND( Af_QA[ k ], QA - 17 ); /* Q17 */
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tmp1 = silk_MLA( tmp1, x_ptr[ n - k - 1 ], Atmp1 ); /* Q17 */
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tmp2 = silk_MLA( tmp2, x_ptr[ subfr_length - n + k ], Atmp1 ); /* Q17 */
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}
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tmp1 = -tmp1; /* Q17 */
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tmp2 = -tmp2; /* Q17 */
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for( k = 0; k <= n; k++ ) {
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CAf[ k ] = silk_SMLAWW( CAf[ k ], tmp1,
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silk_LSHIFT32( (opus_int32)x_ptr[ n - k ], -rshifts - 1 ) ); /* Q( -rshift ) */
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CAb[ k ] = silk_SMLAWW( CAb[ k ], tmp2,
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silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n + k - 1 ], -rshifts - 1 ) ); /* Q( -rshift ) */
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}
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}
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}
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/* Calculate nominator and denominator for the next order reflection (parcor) coefficient */
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tmp1 = C_first_row[ n ]; /* Q( -rshifts ) */
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tmp2 = C_last_row[ n ]; /* Q( -rshifts ) */
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num = 0; /* Q( -rshifts ) */
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nrg = silk_ADD32( CAb[ 0 ], CAf[ 0 ] ); /* Q( 1-rshifts ) */
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for( k = 0; k < n; k++ ) {
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Atmp_QA = Af_QA[ k ];
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lz = silk_CLZ32( silk_abs( Atmp_QA ) ) - 1;
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lz = silk_min( 32 - QA, lz );
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Atmp1 = silk_LSHIFT32( Atmp_QA, lz ); /* Q( QA + lz ) */
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tmp1 = silk_ADD_LSHIFT32( tmp1, silk_SMMUL( C_last_row[ n - k - 1 ], Atmp1 ), 32 - QA - lz ); /* Q( -rshifts ) */
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tmp2 = silk_ADD_LSHIFT32( tmp2, silk_SMMUL( C_first_row[ n - k - 1 ], Atmp1 ), 32 - QA - lz ); /* Q( -rshifts ) */
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num = silk_ADD_LSHIFT32( num, silk_SMMUL( CAb[ n - k ], Atmp1 ), 32 - QA - lz ); /* Q( -rshifts ) */
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nrg = silk_ADD_LSHIFT32( nrg, silk_SMMUL( silk_ADD32( CAb[ k + 1 ], CAf[ k + 1 ] ),
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Atmp1 ), 32 - QA - lz ); /* Q( 1-rshifts ) */
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}
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CAf[ n + 1 ] = tmp1; /* Q( -rshifts ) */
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CAb[ n + 1 ] = tmp2; /* Q( -rshifts ) */
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num = silk_ADD32( num, tmp2 ); /* Q( -rshifts ) */
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num = silk_LSHIFT32( -num, 1 ); /* Q( 1-rshifts ) */
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/* Calculate the next order reflection (parcor) coefficient */
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if( silk_abs( num ) < nrg ) {
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rc_Q31 = silk_DIV32_varQ( num, nrg, 31 );
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} else {
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rc_Q31 = ( num > 0 ) ? silk_int32_MAX : silk_int32_MIN;
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}
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/* Update inverse prediction gain */
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tmp1 = ( (opus_int32)1 << 30 ) - silk_SMMUL( rc_Q31, rc_Q31 );
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tmp1 = silk_LSHIFT( silk_SMMUL( invGain_Q30, tmp1 ), 2 );
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if( tmp1 <= minInvGain_Q30 ) {
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/* Max prediction gain exceeded; set reflection coefficient such that max prediction gain is exactly hit */
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tmp2 = ( (opus_int32)1 << 30 ) - silk_DIV32_varQ( minInvGain_Q30, invGain_Q30, 30 ); /* Q30 */
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rc_Q31 = silk_SQRT_APPROX( tmp2 ); /* Q15 */
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/* Newton-Raphson iteration */
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rc_Q31 = silk_RSHIFT32( rc_Q31 + silk_DIV32( tmp2, rc_Q31 ), 1 ); /* Q15 */
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rc_Q31 = silk_LSHIFT32( rc_Q31, 16 ); /* Q31 */
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if( num < 0 ) {
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/* Ensure adjusted reflection coefficients has the original sign */
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rc_Q31 = -rc_Q31;
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}
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invGain_Q30 = minInvGain_Q30;
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reached_max_gain = 1;
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} else {
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invGain_Q30 = tmp1;
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}
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/* Update the AR coefficients */
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for( k = 0; k < (n + 1) >> 1; k++ ) {
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tmp1 = Af_QA[ k ]; /* QA */
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tmp2 = Af_QA[ n - k - 1 ]; /* QA */
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Af_QA[ k ] = silk_ADD_LSHIFT32( tmp1, silk_SMMUL( tmp2, rc_Q31 ), 1 ); /* QA */
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Af_QA[ n - k - 1 ] = silk_ADD_LSHIFT32( tmp2, silk_SMMUL( tmp1, rc_Q31 ), 1 ); /* QA */
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}
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Af_QA[ n ] = silk_RSHIFT32( rc_Q31, 31 - QA ); /* QA */
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if( reached_max_gain ) {
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/* Reached max prediction gain; set remaining coefficients to zero and exit loop */
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for( k = n + 1; k < D; k++ ) {
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Af_QA[ k ] = 0;
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}
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break;
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}
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/* Update C * Af and C * Ab */
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for( k = 0; k <= n + 1; k++ ) {
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tmp1 = CAf[ k ]; /* Q( -rshifts ) */
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tmp2 = CAb[ n - k + 1 ]; /* Q( -rshifts ) */
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CAf[ k ] = silk_ADD_LSHIFT32( tmp1, silk_SMMUL( tmp2, rc_Q31 ), 1 ); /* Q( -rshifts ) */
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CAb[ n - k + 1 ] = silk_ADD_LSHIFT32( tmp2, silk_SMMUL( tmp1, rc_Q31 ), 1 ); /* Q( -rshifts ) */
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}
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}
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if( reached_max_gain ) {
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for( k = 0; k < D; k++ ) {
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/* Scale coefficients */
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A_Q16[ k ] = -silk_RSHIFT_ROUND( Af_QA[ k ], QA - 16 );
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}
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/* Subtract energy of preceding samples from C0 */
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if( rshifts > 0 ) {
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for( s = 0; s < nb_subfr; s++ ) {
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x_ptr = x + s * subfr_length;
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C0 -= (opus_int32)silk_RSHIFT64( silk_inner_prod16_aligned_64( x_ptr, x_ptr, D ), rshifts );
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}
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} else {
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for( s = 0; s < nb_subfr; s++ ) {
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x_ptr = x + s * subfr_length;
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C0 -= silk_LSHIFT32( silk_inner_prod_aligned( x_ptr, x_ptr, D ), -rshifts );
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}
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}
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/* Approximate residual energy */
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*res_nrg = silk_LSHIFT( silk_SMMUL( invGain_Q30, C0 ), 2 );
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*res_nrg_Q = -rshifts;
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} else {
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/* Return residual energy */
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nrg = CAf[ 0 ]; /* Q( -rshifts ) */
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tmp1 = (opus_int32)1 << 16; /* Q16 */
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for( k = 0; k < D; k++ ) {
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Atmp1 = silk_RSHIFT_ROUND( Af_QA[ k ], QA - 16 ); /* Q16 */
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nrg = silk_SMLAWW( nrg, CAf[ k + 1 ], Atmp1 ); /* Q( -rshifts ) */
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tmp1 = silk_SMLAWW( tmp1, Atmp1, Atmp1 ); /* Q16 */
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A_Q16[ k ] = -Atmp1;
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}
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*res_nrg = silk_SMLAWW( nrg, silk_SMMUL( FIND_LPC_COND_FAC, C0 ), -tmp1 ); /* Q( -rshifts ) */
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*res_nrg_Q = -rshifts;
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}
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}
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