Alexandre Lision | 744f742 | 2013-09-25 11:39:37 -0400 | [diff] [blame] | 1 | /*********************************************************************** |
| 2 | Copyright (c) 2006-2011, Skype Limited. All rights reserved. |
| 3 | Redistribution and use in source and binary forms, with or without |
| 4 | modification, are permitted provided that the following conditions |
| 5 | are met: |
| 6 | - Redistributions of source code must retain the above copyright notice, |
| 7 | this list of conditions and the following disclaimer. |
| 8 | - Redistributions in binary form must reproduce the above copyright |
| 9 | notice, this list of conditions and the following disclaimer in the |
| 10 | documentation and/or other materials provided with the distribution. |
| 11 | - Neither the name of Internet Society, IETF or IETF Trust, nor the |
| 12 | names of specific contributors, may be used to endorse or promote |
| 13 | products derived from this software without specific prior written |
| 14 | permission. |
| 15 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS” |
| 16 | AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 17 | IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 18 | ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
| 19 | LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 20 | CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 21 | SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 22 | INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 23 | CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 24 | ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 25 | POSSIBILITY OF SUCH DAMAGE. |
| 26 | ***********************************************************************/ |
| 27 | |
| 28 | #ifdef HAVE_CONFIG_H |
| 29 | #include "config.h" |
| 30 | #endif |
| 31 | |
| 32 | #include "SigProc_FIX.h" |
| 33 | #include "define.h" |
| 34 | #include "tuning_parameters.h" |
| 35 | |
| 36 | #define MAX_FRAME_SIZE 384 /* subfr_length * nb_subfr = ( 0.005 * 16000 + 16 ) * 4 = 384 */ |
| 37 | |
| 38 | #define QA 25 |
| 39 | #define N_BITS_HEAD_ROOM 2 |
| 40 | #define MIN_RSHIFTS -16 |
| 41 | #define MAX_RSHIFTS (32 - QA) |
| 42 | |
| 43 | /* Compute reflection coefficients from input signal */ |
| 44 | void silk_burg_modified( |
| 45 | opus_int32 *res_nrg, /* O Residual energy */ |
| 46 | opus_int *res_nrg_Q, /* O Residual energy Q value */ |
| 47 | opus_int32 A_Q16[], /* O Prediction coefficients (length order) */ |
| 48 | const opus_int16 x[], /* I Input signal, length: nb_subfr * ( D + subfr_length ) */ |
| 49 | const opus_int32 minInvGain_Q30, /* I Inverse of max prediction gain */ |
| 50 | const opus_int subfr_length, /* I Input signal subframe length (incl. D preceding samples) */ |
| 51 | const opus_int nb_subfr, /* I Number of subframes stacked in x */ |
| 52 | const opus_int D /* I Order */ |
| 53 | ) |
| 54 | { |
| 55 | opus_int k, n, s, lz, rshifts, rshifts_extra, reached_max_gain; |
| 56 | opus_int32 C0, num, nrg, rc_Q31, invGain_Q30, Atmp_QA, Atmp1, tmp1, tmp2, x1, x2; |
| 57 | const opus_int16 *x_ptr; |
| 58 | opus_int32 C_first_row[ SILK_MAX_ORDER_LPC ]; |
| 59 | opus_int32 C_last_row[ SILK_MAX_ORDER_LPC ]; |
| 60 | opus_int32 Af_QA[ SILK_MAX_ORDER_LPC ]; |
| 61 | opus_int32 CAf[ SILK_MAX_ORDER_LPC + 1 ]; |
| 62 | opus_int32 CAb[ SILK_MAX_ORDER_LPC + 1 ]; |
| 63 | |
| 64 | silk_assert( subfr_length * nb_subfr <= MAX_FRAME_SIZE ); |
| 65 | |
| 66 | /* Compute autocorrelations, added over subframes */ |
| 67 | silk_sum_sqr_shift( &C0, &rshifts, x, nb_subfr * subfr_length ); |
| 68 | if( rshifts > MAX_RSHIFTS ) { |
| 69 | C0 = silk_LSHIFT32( C0, rshifts - MAX_RSHIFTS ); |
| 70 | silk_assert( C0 > 0 ); |
| 71 | rshifts = MAX_RSHIFTS; |
| 72 | } else { |
| 73 | lz = silk_CLZ32( C0 ) - 1; |
| 74 | rshifts_extra = N_BITS_HEAD_ROOM - lz; |
| 75 | if( rshifts_extra > 0 ) { |
| 76 | rshifts_extra = silk_min( rshifts_extra, MAX_RSHIFTS - rshifts ); |
| 77 | C0 = silk_RSHIFT32( C0, rshifts_extra ); |
| 78 | } else { |
| 79 | rshifts_extra = silk_max( rshifts_extra, MIN_RSHIFTS - rshifts ); |
| 80 | C0 = silk_LSHIFT32( C0, -rshifts_extra ); |
| 81 | } |
| 82 | rshifts += rshifts_extra; |
| 83 | } |
| 84 | CAb[ 0 ] = CAf[ 0 ] = C0 + silk_SMMUL( SILK_FIX_CONST( FIND_LPC_COND_FAC, 32 ), C0 ) + 1; /* Q(-rshifts) */ |
| 85 | silk_memset( C_first_row, 0, SILK_MAX_ORDER_LPC * sizeof( opus_int32 ) ); |
| 86 | if( rshifts > 0 ) { |
| 87 | for( s = 0; s < nb_subfr; s++ ) { |
| 88 | x_ptr = x + s * subfr_length; |
| 89 | for( n = 1; n < D + 1; n++ ) { |
| 90 | C_first_row[ n - 1 ] += (opus_int32)silk_RSHIFT64( |
| 91 | silk_inner_prod16_aligned_64( x_ptr, x_ptr + n, subfr_length - n ), rshifts ); |
| 92 | } |
| 93 | } |
| 94 | } else { |
| 95 | for( s = 0; s < nb_subfr; s++ ) { |
| 96 | x_ptr = x + s * subfr_length; |
| 97 | for( n = 1; n < D + 1; n++ ) { |
| 98 | C_first_row[ n - 1 ] += silk_LSHIFT32( |
| 99 | silk_inner_prod_aligned( x_ptr, x_ptr + n, subfr_length - n ), -rshifts ); |
| 100 | } |
| 101 | } |
| 102 | } |
| 103 | silk_memcpy( C_last_row, C_first_row, SILK_MAX_ORDER_LPC * sizeof( opus_int32 ) ); |
| 104 | |
| 105 | /* Initialize */ |
| 106 | CAb[ 0 ] = CAf[ 0 ] = C0 + silk_SMMUL( SILK_FIX_CONST( FIND_LPC_COND_FAC, 32 ), C0 ) + 1; /* Q(-rshifts) */ |
| 107 | |
| 108 | invGain_Q30 = (opus_int32)1 << 30; |
| 109 | reached_max_gain = 0; |
| 110 | for( n = 0; n < D; n++ ) { |
| 111 | /* Update first row of correlation matrix (without first element) */ |
| 112 | /* Update last row of correlation matrix (without last element, stored in reversed order) */ |
| 113 | /* Update C * Af */ |
| 114 | /* Update C * flipud(Af) (stored in reversed order) */ |
| 115 | if( rshifts > -2 ) { |
| 116 | for( s = 0; s < nb_subfr; s++ ) { |
| 117 | x_ptr = x + s * subfr_length; |
| 118 | x1 = -silk_LSHIFT32( (opus_int32)x_ptr[ n ], 16 - rshifts ); /* Q(16-rshifts) */ |
| 119 | x2 = -silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], 16 - rshifts ); /* Q(16-rshifts) */ |
| 120 | tmp1 = silk_LSHIFT32( (opus_int32)x_ptr[ n ], QA - 16 ); /* Q(QA-16) */ |
| 121 | tmp2 = silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], QA - 16 ); /* Q(QA-16) */ |
| 122 | for( k = 0; k < n; k++ ) { |
| 123 | C_first_row[ k ] = silk_SMLAWB( C_first_row[ k ], x1, x_ptr[ n - k - 1 ] ); /* Q( -rshifts ) */ |
| 124 | C_last_row[ k ] = silk_SMLAWB( C_last_row[ k ], x2, x_ptr[ subfr_length - n + k ] ); /* Q( -rshifts ) */ |
| 125 | Atmp_QA = Af_QA[ k ]; |
| 126 | tmp1 = silk_SMLAWB( tmp1, Atmp_QA, x_ptr[ n - k - 1 ] ); /* Q(QA-16) */ |
| 127 | tmp2 = silk_SMLAWB( tmp2, Atmp_QA, x_ptr[ subfr_length - n + k ] ); /* Q(QA-16) */ |
| 128 | } |
| 129 | tmp1 = silk_LSHIFT32( -tmp1, 32 - QA - rshifts ); /* Q(16-rshifts) */ |
| 130 | tmp2 = silk_LSHIFT32( -tmp2, 32 - QA - rshifts ); /* Q(16-rshifts) */ |
| 131 | for( k = 0; k <= n; k++ ) { |
| 132 | CAf[ k ] = silk_SMLAWB( CAf[ k ], tmp1, x_ptr[ n - k ] ); /* Q( -rshift ) */ |
| 133 | CAb[ k ] = silk_SMLAWB( CAb[ k ], tmp2, x_ptr[ subfr_length - n + k - 1 ] ); /* Q( -rshift ) */ |
| 134 | } |
| 135 | } |
| 136 | } else { |
| 137 | for( s = 0; s < nb_subfr; s++ ) { |
| 138 | x_ptr = x + s * subfr_length; |
| 139 | x1 = -silk_LSHIFT32( (opus_int32)x_ptr[ n ], -rshifts ); /* Q( -rshifts ) */ |
| 140 | x2 = -silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], -rshifts ); /* Q( -rshifts ) */ |
| 141 | tmp1 = silk_LSHIFT32( (opus_int32)x_ptr[ n ], 17 ); /* Q17 */ |
| 142 | tmp2 = silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], 17 ); /* Q17 */ |
| 143 | for( k = 0; k < n; k++ ) { |
| 144 | C_first_row[ k ] = silk_MLA( C_first_row[ k ], x1, x_ptr[ n - k - 1 ] ); /* Q( -rshifts ) */ |
| 145 | C_last_row[ k ] = silk_MLA( C_last_row[ k ], x2, x_ptr[ subfr_length - n + k ] ); /* Q( -rshifts ) */ |
| 146 | Atmp1 = silk_RSHIFT_ROUND( Af_QA[ k ], QA - 17 ); /* Q17 */ |
| 147 | tmp1 = silk_MLA( tmp1, x_ptr[ n - k - 1 ], Atmp1 ); /* Q17 */ |
| 148 | tmp2 = silk_MLA( tmp2, x_ptr[ subfr_length - n + k ], Atmp1 ); /* Q17 */ |
| 149 | } |
| 150 | tmp1 = -tmp1; /* Q17 */ |
| 151 | tmp2 = -tmp2; /* Q17 */ |
| 152 | for( k = 0; k <= n; k++ ) { |
| 153 | CAf[ k ] = silk_SMLAWW( CAf[ k ], tmp1, |
| 154 | silk_LSHIFT32( (opus_int32)x_ptr[ n - k ], -rshifts - 1 ) ); /* Q( -rshift ) */ |
| 155 | CAb[ k ] = silk_SMLAWW( CAb[ k ], tmp2, |
| 156 | silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n + k - 1 ], -rshifts - 1 ) ); /* Q( -rshift ) */ |
| 157 | } |
| 158 | } |
| 159 | } |
| 160 | |
| 161 | /* Calculate nominator and denominator for the next order reflection (parcor) coefficient */ |
| 162 | tmp1 = C_first_row[ n ]; /* Q( -rshifts ) */ |
| 163 | tmp2 = C_last_row[ n ]; /* Q( -rshifts ) */ |
| 164 | num = 0; /* Q( -rshifts ) */ |
| 165 | nrg = silk_ADD32( CAb[ 0 ], CAf[ 0 ] ); /* Q( 1-rshifts ) */ |
| 166 | for( k = 0; k < n; k++ ) { |
| 167 | Atmp_QA = Af_QA[ k ]; |
| 168 | lz = silk_CLZ32( silk_abs( Atmp_QA ) ) - 1; |
| 169 | lz = silk_min( 32 - QA, lz ); |
| 170 | Atmp1 = silk_LSHIFT32( Atmp_QA, lz ); /* Q( QA + lz ) */ |
| 171 | |
| 172 | tmp1 = silk_ADD_LSHIFT32( tmp1, silk_SMMUL( C_last_row[ n - k - 1 ], Atmp1 ), 32 - QA - lz ); /* Q( -rshifts ) */ |
| 173 | tmp2 = silk_ADD_LSHIFT32( tmp2, silk_SMMUL( C_first_row[ n - k - 1 ], Atmp1 ), 32 - QA - lz ); /* Q( -rshifts ) */ |
| 174 | num = silk_ADD_LSHIFT32( num, silk_SMMUL( CAb[ n - k ], Atmp1 ), 32 - QA - lz ); /* Q( -rshifts ) */ |
| 175 | nrg = silk_ADD_LSHIFT32( nrg, silk_SMMUL( silk_ADD32( CAb[ k + 1 ], CAf[ k + 1 ] ), |
| 176 | Atmp1 ), 32 - QA - lz ); /* Q( 1-rshifts ) */ |
| 177 | } |
| 178 | CAf[ n + 1 ] = tmp1; /* Q( -rshifts ) */ |
| 179 | CAb[ n + 1 ] = tmp2; /* Q( -rshifts ) */ |
| 180 | num = silk_ADD32( num, tmp2 ); /* Q( -rshifts ) */ |
| 181 | num = silk_LSHIFT32( -num, 1 ); /* Q( 1-rshifts ) */ |
| 182 | |
| 183 | /* Calculate the next order reflection (parcor) coefficient */ |
| 184 | if( silk_abs( num ) < nrg ) { |
| 185 | rc_Q31 = silk_DIV32_varQ( num, nrg, 31 ); |
| 186 | } else { |
| 187 | rc_Q31 = ( num > 0 ) ? silk_int32_MAX : silk_int32_MIN; |
| 188 | } |
| 189 | |
| 190 | /* Update inverse prediction gain */ |
| 191 | tmp1 = ( (opus_int32)1 << 30 ) - silk_SMMUL( rc_Q31, rc_Q31 ); |
| 192 | tmp1 = silk_LSHIFT( silk_SMMUL( invGain_Q30, tmp1 ), 2 ); |
| 193 | if( tmp1 <= minInvGain_Q30 ) { |
| 194 | /* Max prediction gain exceeded; set reflection coefficient such that max prediction gain is exactly hit */ |
| 195 | tmp2 = ( (opus_int32)1 << 30 ) - silk_DIV32_varQ( minInvGain_Q30, invGain_Q30, 30 ); /* Q30 */ |
| 196 | rc_Q31 = silk_SQRT_APPROX( tmp2 ); /* Q15 */ |
| 197 | /* Newton-Raphson iteration */ |
| 198 | rc_Q31 = silk_RSHIFT32( rc_Q31 + silk_DIV32( tmp2, rc_Q31 ), 1 ); /* Q15 */ |
| 199 | rc_Q31 = silk_LSHIFT32( rc_Q31, 16 ); /* Q31 */ |
| 200 | if( num < 0 ) { |
| 201 | /* Ensure adjusted reflection coefficients has the original sign */ |
| 202 | rc_Q31 = -rc_Q31; |
| 203 | } |
| 204 | invGain_Q30 = minInvGain_Q30; |
| 205 | reached_max_gain = 1; |
| 206 | } else { |
| 207 | invGain_Q30 = tmp1; |
| 208 | } |
| 209 | |
| 210 | /* Update the AR coefficients */ |
| 211 | for( k = 0; k < (n + 1) >> 1; k++ ) { |
| 212 | tmp1 = Af_QA[ k ]; /* QA */ |
| 213 | tmp2 = Af_QA[ n - k - 1 ]; /* QA */ |
| 214 | Af_QA[ k ] = silk_ADD_LSHIFT32( tmp1, silk_SMMUL( tmp2, rc_Q31 ), 1 ); /* QA */ |
| 215 | Af_QA[ n - k - 1 ] = silk_ADD_LSHIFT32( tmp2, silk_SMMUL( tmp1, rc_Q31 ), 1 ); /* QA */ |
| 216 | } |
| 217 | Af_QA[ n ] = silk_RSHIFT32( rc_Q31, 31 - QA ); /* QA */ |
| 218 | |
| 219 | if( reached_max_gain ) { |
| 220 | /* Reached max prediction gain; set remaining coefficients to zero and exit loop */ |
| 221 | for( k = n + 1; k < D; k++ ) { |
| 222 | Af_QA[ k ] = 0; |
| 223 | } |
| 224 | break; |
| 225 | } |
| 226 | |
| 227 | /* Update C * Af and C * Ab */ |
| 228 | for( k = 0; k <= n + 1; k++ ) { |
| 229 | tmp1 = CAf[ k ]; /* Q( -rshifts ) */ |
| 230 | tmp2 = CAb[ n - k + 1 ]; /* Q( -rshifts ) */ |
| 231 | CAf[ k ] = silk_ADD_LSHIFT32( tmp1, silk_SMMUL( tmp2, rc_Q31 ), 1 ); /* Q( -rshifts ) */ |
| 232 | CAb[ n - k + 1 ] = silk_ADD_LSHIFT32( tmp2, silk_SMMUL( tmp1, rc_Q31 ), 1 ); /* Q( -rshifts ) */ |
| 233 | } |
| 234 | } |
| 235 | |
| 236 | if( reached_max_gain ) { |
| 237 | for( k = 0; k < D; k++ ) { |
| 238 | /* Scale coefficients */ |
| 239 | A_Q16[ k ] = -silk_RSHIFT_ROUND( Af_QA[ k ], QA - 16 ); |
| 240 | } |
| 241 | /* Subtract energy of preceding samples from C0 */ |
| 242 | if( rshifts > 0 ) { |
| 243 | for( s = 0; s < nb_subfr; s++ ) { |
| 244 | x_ptr = x + s * subfr_length; |
| 245 | C0 -= (opus_int32)silk_RSHIFT64( silk_inner_prod16_aligned_64( x_ptr, x_ptr, D ), rshifts ); |
| 246 | } |
| 247 | } else { |
| 248 | for( s = 0; s < nb_subfr; s++ ) { |
| 249 | x_ptr = x + s * subfr_length; |
| 250 | C0 -= silk_LSHIFT32( silk_inner_prod_aligned( x_ptr, x_ptr, D ), -rshifts ); |
| 251 | } |
| 252 | } |
| 253 | /* Approximate residual energy */ |
| 254 | *res_nrg = silk_LSHIFT( silk_SMMUL( invGain_Q30, C0 ), 2 ); |
| 255 | *res_nrg_Q = -rshifts; |
| 256 | } else { |
| 257 | /* Return residual energy */ |
| 258 | nrg = CAf[ 0 ]; /* Q( -rshifts ) */ |
| 259 | tmp1 = (opus_int32)1 << 16; /* Q16 */ |
| 260 | for( k = 0; k < D; k++ ) { |
| 261 | Atmp1 = silk_RSHIFT_ROUND( Af_QA[ k ], QA - 16 ); /* Q16 */ |
| 262 | nrg = silk_SMLAWW( nrg, CAf[ k + 1 ], Atmp1 ); /* Q( -rshifts ) */ |
| 263 | tmp1 = silk_SMLAWW( tmp1, Atmp1, Atmp1 ); /* Q16 */ |
| 264 | A_Q16[ k ] = -Atmp1; |
| 265 | } |
| 266 | *res_nrg = silk_SMLAWW( nrg, silk_SMMUL( SILK_FIX_CONST( FIND_LPC_COND_FAC, 32 ), C0 ), -tmp1 );/* Q( -rshifts ) */ |
| 267 | *res_nrg_Q = -rshifts; |
| 268 | } |
| 269 | } |