Chris@69: /*********************************************************************** Chris@69: Copyright (c) 2006-2011, Skype Limited. All rights reserved. Chris@69: Redistribution and use in source and binary forms, with or without Chris@69: modification, are permitted provided that the following conditions Chris@69: are met: Chris@69: - Redistributions of source code must retain the above copyright notice, Chris@69: this list of conditions and the following disclaimer. Chris@69: - Redistributions in binary form must reproduce the above copyright Chris@69: notice, this list of conditions and the following disclaimer in the Chris@69: documentation and/or other materials provided with the distribution. Chris@69: - Neither the name of Internet Society, IETF or IETF Trust, nor the Chris@69: names of specific contributors, may be used to endorse or promote Chris@69: products derived from this software without specific prior written Chris@69: permission. Chris@69: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" Chris@69: AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE Chris@69: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE Chris@69: ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE Chris@69: LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR Chris@69: CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF Chris@69: SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS Chris@69: INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN Chris@69: CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) Chris@69: ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE Chris@69: POSSIBILITY OF SUCH DAMAGE. Chris@69: ***********************************************************************/ Chris@69: Chris@69: #ifdef HAVE_CONFIG_H Chris@69: #include "config.h" Chris@69: #endif Chris@69: Chris@69: #include "SigProc_FLP.h" Chris@69: #include "tuning_parameters.h" Chris@69: #include "define.h" Chris@69: Chris@69: #define MAX_FRAME_SIZE 384 /* subfr_length * nb_subfr = ( 0.005 * 16000 + 16 ) * 4 = 384*/ Chris@69: Chris@69: /* Compute reflection coefficients from input signal */ Chris@69: silk_float silk_burg_modified_FLP( /* O returns residual energy */ Chris@69: silk_float A[], /* O prediction coefficients (length order) */ Chris@69: const silk_float x[], /* I input signal, length: nb_subfr*(D+L_sub) */ Chris@69: const silk_float minInvGain, /* I minimum inverse prediction gain */ Chris@69: const opus_int subfr_length, /* I input signal subframe length (incl. D preceding samples) */ Chris@69: const opus_int nb_subfr, /* I number of subframes stacked in x */ Chris@69: const opus_int D /* I order */ Chris@69: ) Chris@69: { Chris@69: opus_int k, n, s, reached_max_gain; Chris@69: double C0, invGain, num, nrg_f, nrg_b, rc, Atmp, tmp1, tmp2; Chris@69: const silk_float *x_ptr; Chris@69: double C_first_row[ SILK_MAX_ORDER_LPC ], C_last_row[ SILK_MAX_ORDER_LPC ]; Chris@69: double CAf[ SILK_MAX_ORDER_LPC + 1 ], CAb[ SILK_MAX_ORDER_LPC + 1 ]; Chris@69: double Af[ SILK_MAX_ORDER_LPC ]; Chris@69: Chris@69: celt_assert( subfr_length * nb_subfr <= MAX_FRAME_SIZE ); Chris@69: Chris@69: /* Compute autocorrelations, added over subframes */ Chris@69: C0 = silk_energy_FLP( x, nb_subfr * subfr_length ); Chris@69: silk_memset( C_first_row, 0, SILK_MAX_ORDER_LPC * sizeof( double ) ); Chris@69: for( s = 0; s < nb_subfr; s++ ) { Chris@69: x_ptr = x + s * subfr_length; Chris@69: for( n = 1; n < D + 1; n++ ) { Chris@69: C_first_row[ n - 1 ] += silk_inner_product_FLP( x_ptr, x_ptr + n, subfr_length - n ); Chris@69: } Chris@69: } Chris@69: silk_memcpy( C_last_row, C_first_row, SILK_MAX_ORDER_LPC * sizeof( double ) ); Chris@69: Chris@69: /* Initialize */ Chris@69: CAb[ 0 ] = CAf[ 0 ] = C0 + FIND_LPC_COND_FAC * C0 + 1e-9f; Chris@69: invGain = 1.0f; Chris@69: reached_max_gain = 0; Chris@69: for( n = 0; n < D; n++ ) { Chris@69: /* Update first row of correlation matrix (without first element) */ Chris@69: /* Update last row of correlation matrix (without last element, stored in reversed order) */ Chris@69: /* Update C * Af */ Chris@69: /* Update C * flipud(Af) (stored in reversed order) */ Chris@69: for( s = 0; s < nb_subfr; s++ ) { Chris@69: x_ptr = x + s * subfr_length; Chris@69: tmp1 = x_ptr[ n ]; Chris@69: tmp2 = x_ptr[ subfr_length - n - 1 ]; Chris@69: for( k = 0; k < n; k++ ) { Chris@69: C_first_row[ k ] -= x_ptr[ n ] * x_ptr[ n - k - 1 ]; Chris@69: C_last_row[ k ] -= x_ptr[ subfr_length - n - 1 ] * x_ptr[ subfr_length - n + k ]; Chris@69: Atmp = Af[ k ]; Chris@69: tmp1 += x_ptr[ n - k - 1 ] * Atmp; Chris@69: tmp2 += x_ptr[ subfr_length - n + k ] * Atmp; Chris@69: } Chris@69: for( k = 0; k <= n; k++ ) { Chris@69: CAf[ k ] -= tmp1 * x_ptr[ n - k ]; Chris@69: CAb[ k ] -= tmp2 * x_ptr[ subfr_length - n + k - 1 ]; Chris@69: } Chris@69: } Chris@69: tmp1 = C_first_row[ n ]; Chris@69: tmp2 = C_last_row[ n ]; Chris@69: for( k = 0; k < n; k++ ) { Chris@69: Atmp = Af[ k ]; Chris@69: tmp1 += C_last_row[ n - k - 1 ] * Atmp; Chris@69: tmp2 += C_first_row[ n - k - 1 ] * Atmp; Chris@69: } Chris@69: CAf[ n + 1 ] = tmp1; Chris@69: CAb[ n + 1 ] = tmp2; Chris@69: Chris@69: /* Calculate nominator and denominator for the next order reflection (parcor) coefficient */ Chris@69: num = CAb[ n + 1 ]; Chris@69: nrg_b = CAb[ 0 ]; Chris@69: nrg_f = CAf[ 0 ]; Chris@69: for( k = 0; k < n; k++ ) { Chris@69: Atmp = Af[ k ]; Chris@69: num += CAb[ n - k ] * Atmp; Chris@69: nrg_b += CAb[ k + 1 ] * Atmp; Chris@69: nrg_f += CAf[ k + 1 ] * Atmp; Chris@69: } Chris@69: silk_assert( nrg_f > 0.0 ); Chris@69: silk_assert( nrg_b > 0.0 ); Chris@69: Chris@69: /* Calculate the next order reflection (parcor) coefficient */ Chris@69: rc = -2.0 * num / ( nrg_f + nrg_b ); Chris@69: silk_assert( rc > -1.0 && rc < 1.0 ); Chris@69: Chris@69: /* Update inverse prediction gain */ Chris@69: tmp1 = invGain * ( 1.0 - rc * rc ); Chris@69: if( tmp1 <= minInvGain ) { Chris@69: /* Max prediction gain exceeded; set reflection coefficient such that max prediction gain is exactly hit */ Chris@69: rc = sqrt( 1.0 - minInvGain / invGain ); Chris@69: if( num > 0 ) { Chris@69: /* Ensure adjusted reflection coefficients has the original sign */ Chris@69: rc = -rc; Chris@69: } Chris@69: invGain = minInvGain; Chris@69: reached_max_gain = 1; Chris@69: } else { Chris@69: invGain = tmp1; Chris@69: } Chris@69: Chris@69: /* Update the AR coefficients */ Chris@69: for( k = 0; k < (n + 1) >> 1; k++ ) { Chris@69: tmp1 = Af[ k ]; Chris@69: tmp2 = Af[ n - k - 1 ]; Chris@69: Af[ k ] = tmp1 + rc * tmp2; Chris@69: Af[ n - k - 1 ] = tmp2 + rc * tmp1; Chris@69: } Chris@69: Af[ n ] = rc; Chris@69: Chris@69: if( reached_max_gain ) { Chris@69: /* Reached max prediction gain; set remaining coefficients to zero and exit loop */ Chris@69: for( k = n + 1; k < D; k++ ) { Chris@69: Af[ k ] = 0.0; Chris@69: } Chris@69: break; Chris@69: } Chris@69: Chris@69: /* Update C * Af and C * Ab */ Chris@69: for( k = 0; k <= n + 1; k++ ) { Chris@69: tmp1 = CAf[ k ]; Chris@69: CAf[ k ] += rc * CAb[ n - k + 1 ]; Chris@69: CAb[ n - k + 1 ] += rc * tmp1; Chris@69: } Chris@69: } Chris@69: Chris@69: if( reached_max_gain ) { Chris@69: /* Convert to silk_float */ Chris@69: for( k = 0; k < D; k++ ) { Chris@69: A[ k ] = (silk_float)( -Af[ k ] ); Chris@69: } Chris@69: /* Subtract energy of preceding samples from C0 */ Chris@69: for( s = 0; s < nb_subfr; s++ ) { Chris@69: C0 -= silk_energy_FLP( x + s * subfr_length, D ); Chris@69: } Chris@69: /* Approximate residual energy */ Chris@69: nrg_f = C0 * invGain; Chris@69: } else { Chris@69: /* Compute residual energy and store coefficients as silk_float */ Chris@69: nrg_f = CAf[ 0 ]; Chris@69: tmp1 = 1.0; Chris@69: for( k = 0; k < D; k++ ) { Chris@69: Atmp = Af[ k ]; Chris@69: nrg_f += CAf[ k + 1 ] * Atmp; Chris@69: tmp1 += Atmp * Atmp; Chris@69: A[ k ] = (silk_float)(-Atmp); Chris@69: } Chris@69: nrg_f -= FIND_LPC_COND_FAC * C0 * tmp1; Chris@69: } Chris@69: Chris@69: /* Return residual energy */ Chris@69: return (silk_float)nrg_f; Chris@69: }