cannam@154: /*********************************************************************** cannam@154: Copyright (c) 2006-2011, Skype Limited. All rights reserved. cannam@154: Redistribution and use in source and binary forms, with or without cannam@154: modification, are permitted provided that the following conditions cannam@154: are met: cannam@154: - Redistributions of source code must retain the above copyright notice, cannam@154: this list of conditions and the following disclaimer. cannam@154: - Redistributions in binary form must reproduce the above copyright cannam@154: notice, this list of conditions and the following disclaimer in the cannam@154: documentation and/or other materials provided with the distribution. cannam@154: - Neither the name of Internet Society, IETF or IETF Trust, nor the cannam@154: names of specific contributors, may be used to endorse or promote cannam@154: products derived from this software without specific prior written cannam@154: permission. cannam@154: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" cannam@154: AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE cannam@154: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE cannam@154: ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE cannam@154: LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR cannam@154: CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF cannam@154: SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS cannam@154: INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN cannam@154: CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) cannam@154: ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE cannam@154: POSSIBILITY OF SUCH DAMAGE. cannam@154: ***********************************************************************/ cannam@154: cannam@154: #ifdef HAVE_CONFIG_H cannam@154: #include "config.h" cannam@154: #endif cannam@154: cannam@154: #include "SigProc_FLP.h" cannam@154: #include "tuning_parameters.h" cannam@154: #include "define.h" cannam@154: cannam@154: #define MAX_FRAME_SIZE 384 /* subfr_length * nb_subfr = ( 0.005 * 16000 + 16 ) * 4 = 384*/ cannam@154: cannam@154: /* Compute reflection coefficients from input signal */ cannam@154: silk_float silk_burg_modified_FLP( /* O returns residual energy */ cannam@154: silk_float A[], /* O prediction coefficients (length order) */ cannam@154: const silk_float x[], /* I input signal, length: nb_subfr*(D+L_sub) */ cannam@154: const silk_float minInvGain, /* I minimum inverse prediction gain */ cannam@154: const opus_int subfr_length, /* I input signal subframe length (incl. D preceding samples) */ cannam@154: const opus_int nb_subfr, /* I number of subframes stacked in x */ cannam@154: const opus_int D /* I order */ cannam@154: ) cannam@154: { cannam@154: opus_int k, n, s, reached_max_gain; cannam@154: double C0, invGain, num, nrg_f, nrg_b, rc, Atmp, tmp1, tmp2; cannam@154: const silk_float *x_ptr; cannam@154: double C_first_row[ SILK_MAX_ORDER_LPC ], C_last_row[ SILK_MAX_ORDER_LPC ]; cannam@154: double CAf[ SILK_MAX_ORDER_LPC + 1 ], CAb[ SILK_MAX_ORDER_LPC + 1 ]; cannam@154: double Af[ SILK_MAX_ORDER_LPC ]; cannam@154: cannam@154: celt_assert( subfr_length * nb_subfr <= MAX_FRAME_SIZE ); cannam@154: cannam@154: /* Compute autocorrelations, added over subframes */ cannam@154: C0 = silk_energy_FLP( x, nb_subfr * subfr_length ); cannam@154: silk_memset( C_first_row, 0, SILK_MAX_ORDER_LPC * sizeof( double ) ); cannam@154: for( s = 0; s < nb_subfr; s++ ) { cannam@154: x_ptr = x + s * subfr_length; cannam@154: for( n = 1; n < D + 1; n++ ) { cannam@154: C_first_row[ n - 1 ] += silk_inner_product_FLP( x_ptr, x_ptr + n, subfr_length - n ); cannam@154: } cannam@154: } cannam@154: silk_memcpy( C_last_row, C_first_row, SILK_MAX_ORDER_LPC * sizeof( double ) ); cannam@154: cannam@154: /* Initialize */ cannam@154: CAb[ 0 ] = CAf[ 0 ] = C0 + FIND_LPC_COND_FAC * C0 + 1e-9f; cannam@154: invGain = 1.0f; cannam@154: reached_max_gain = 0; cannam@154: for( n = 0; n < D; n++ ) { cannam@154: /* Update first row of correlation matrix (without first element) */ cannam@154: /* Update last row of correlation matrix (without last element, stored in reversed order) */ cannam@154: /* Update C * Af */ cannam@154: /* Update C * flipud(Af) (stored in reversed order) */ cannam@154: for( s = 0; s < nb_subfr; s++ ) { cannam@154: x_ptr = x + s * subfr_length; cannam@154: tmp1 = x_ptr[ n ]; cannam@154: tmp2 = x_ptr[ subfr_length - n - 1 ]; cannam@154: for( k = 0; k < n; k++ ) { cannam@154: C_first_row[ k ] -= x_ptr[ n ] * x_ptr[ n - k - 1 ]; cannam@154: C_last_row[ k ] -= x_ptr[ subfr_length - n - 1 ] * x_ptr[ subfr_length - n + k ]; cannam@154: Atmp = Af[ k ]; cannam@154: tmp1 += x_ptr[ n - k - 1 ] * Atmp; cannam@154: tmp2 += x_ptr[ subfr_length - n + k ] * Atmp; cannam@154: } cannam@154: for( k = 0; k <= n; k++ ) { cannam@154: CAf[ k ] -= tmp1 * x_ptr[ n - k ]; cannam@154: CAb[ k ] -= tmp2 * x_ptr[ subfr_length - n + k - 1 ]; cannam@154: } cannam@154: } cannam@154: tmp1 = C_first_row[ n ]; cannam@154: tmp2 = C_last_row[ n ]; cannam@154: for( k = 0; k < n; k++ ) { cannam@154: Atmp = Af[ k ]; cannam@154: tmp1 += C_last_row[ n - k - 1 ] * Atmp; cannam@154: tmp2 += C_first_row[ n - k - 1 ] * Atmp; cannam@154: } cannam@154: CAf[ n + 1 ] = tmp1; cannam@154: CAb[ n + 1 ] = tmp2; cannam@154: cannam@154: /* Calculate nominator and denominator for the next order reflection (parcor) coefficient */ cannam@154: num = CAb[ n + 1 ]; cannam@154: nrg_b = CAb[ 0 ]; cannam@154: nrg_f = CAf[ 0 ]; cannam@154: for( k = 0; k < n; k++ ) { cannam@154: Atmp = Af[ k ]; cannam@154: num += CAb[ n - k ] * Atmp; cannam@154: nrg_b += CAb[ k + 1 ] * Atmp; cannam@154: nrg_f += CAf[ k + 1 ] * Atmp; cannam@154: } cannam@154: silk_assert( nrg_f > 0.0 ); cannam@154: silk_assert( nrg_b > 0.0 ); cannam@154: cannam@154: /* Calculate the next order reflection (parcor) coefficient */ cannam@154: rc = -2.0 * num / ( nrg_f + nrg_b ); cannam@154: silk_assert( rc > -1.0 && rc < 1.0 ); cannam@154: cannam@154: /* Update inverse prediction gain */ cannam@154: tmp1 = invGain * ( 1.0 - rc * rc ); cannam@154: if( tmp1 <= minInvGain ) { cannam@154: /* Max prediction gain exceeded; set reflection coefficient such that max prediction gain is exactly hit */ cannam@154: rc = sqrt( 1.0 - minInvGain / invGain ); cannam@154: if( num > 0 ) { cannam@154: /* Ensure adjusted reflection coefficients has the original sign */ cannam@154: rc = -rc; cannam@154: } cannam@154: invGain = minInvGain; cannam@154: reached_max_gain = 1; cannam@154: } else { cannam@154: invGain = tmp1; cannam@154: } cannam@154: cannam@154: /* Update the AR coefficients */ cannam@154: for( k = 0; k < (n + 1) >> 1; k++ ) { cannam@154: tmp1 = Af[ k ]; cannam@154: tmp2 = Af[ n - k - 1 ]; cannam@154: Af[ k ] = tmp1 + rc * tmp2; cannam@154: Af[ n - k - 1 ] = tmp2 + rc * tmp1; cannam@154: } cannam@154: Af[ n ] = rc; cannam@154: cannam@154: if( reached_max_gain ) { cannam@154: /* Reached max prediction gain; set remaining coefficients to zero and exit loop */ cannam@154: for( k = n + 1; k < D; k++ ) { cannam@154: Af[ k ] = 0.0; cannam@154: } cannam@154: break; cannam@154: } cannam@154: cannam@154: /* Update C * Af and C * Ab */ cannam@154: for( k = 0; k <= n + 1; k++ ) { cannam@154: tmp1 = CAf[ k ]; cannam@154: CAf[ k ] += rc * CAb[ n - k + 1 ]; cannam@154: CAb[ n - k + 1 ] += rc * tmp1; cannam@154: } cannam@154: } cannam@154: cannam@154: if( reached_max_gain ) { cannam@154: /* Convert to silk_float */ cannam@154: for( k = 0; k < D; k++ ) { cannam@154: A[ k ] = (silk_float)( -Af[ k ] ); cannam@154: } cannam@154: /* Subtract energy of preceding samples from C0 */ cannam@154: for( s = 0; s < nb_subfr; s++ ) { cannam@154: C0 -= silk_energy_FLP( x + s * subfr_length, D ); cannam@154: } cannam@154: /* Approximate residual energy */ cannam@154: nrg_f = C0 * invGain; cannam@154: } else { cannam@154: /* Compute residual energy and store coefficients as silk_float */ cannam@154: nrg_f = CAf[ 0 ]; cannam@154: tmp1 = 1.0; cannam@154: for( k = 0; k < D; k++ ) { cannam@154: Atmp = Af[ k ]; cannam@154: nrg_f += CAf[ k + 1 ] * Atmp; cannam@154: tmp1 += Atmp * Atmp; cannam@154: A[ k ] = (silk_float)(-Atmp); cannam@154: } cannam@154: nrg_f -= FIND_LPC_COND_FAC * C0 * tmp1; cannam@154: } cannam@154: cannam@154: /* Return residual energy */ cannam@154: return (silk_float)nrg_f; cannam@154: }