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 | |
| 34 | #define QA 24 |
| 35 | #define A_LIMIT SILK_FIX_CONST( 0.99975, QA ) |
| 36 | |
| 37 | #define MUL32_FRAC_Q(a32, b32, Q) ((opus_int32)(silk_RSHIFT_ROUND64(silk_SMULL(a32, b32), Q))) |
| 38 | |
| 39 | /* Compute inverse of LPC prediction gain, and */ |
| 40 | /* test if LPC coefficients are stable (all poles within unit circle) */ |
| 41 | static opus_int32 LPC_inverse_pred_gain_QA( /* O Returns inverse prediction gain in energy domain, Q30 */ |
| 42 | opus_int32 A_QA[ 2 ][ SILK_MAX_ORDER_LPC ], /* I Prediction coefficients */ |
| 43 | const opus_int order /* I Prediction order */ |
| 44 | ) |
| 45 | { |
| 46 | opus_int k, n, mult2Q; |
| 47 | opus_int32 invGain_Q30, rc_Q31, rc_mult1_Q30, rc_mult2, tmp_QA; |
| 48 | opus_int32 *Aold_QA, *Anew_QA; |
| 49 | |
| 50 | Anew_QA = A_QA[ order & 1 ]; |
| 51 | |
| 52 | invGain_Q30 = (opus_int32)1 << 30; |
| 53 | for( k = order - 1; k > 0; k-- ) { |
| 54 | /* Check for stability */ |
| 55 | if( ( Anew_QA[ k ] > A_LIMIT ) || ( Anew_QA[ k ] < -A_LIMIT ) ) { |
| 56 | return 0; |
| 57 | } |
| 58 | |
| 59 | /* Set RC equal to negated AR coef */ |
| 60 | rc_Q31 = -silk_LSHIFT( Anew_QA[ k ], 31 - QA ); |
| 61 | |
| 62 | /* rc_mult1_Q30 range: [ 1 : 2^30 ] */ |
| 63 | rc_mult1_Q30 = ( (opus_int32)1 << 30 ) - silk_SMMUL( rc_Q31, rc_Q31 ); |
| 64 | silk_assert( rc_mult1_Q30 > ( 1 << 15 ) ); /* reduce A_LIMIT if fails */ |
| 65 | silk_assert( rc_mult1_Q30 <= ( 1 << 30 ) ); |
| 66 | |
| 67 | /* rc_mult2 range: [ 2^30 : silk_int32_MAX ] */ |
| 68 | mult2Q = 32 - silk_CLZ32( silk_abs( rc_mult1_Q30 ) ); |
| 69 | rc_mult2 = silk_INVERSE32_varQ( rc_mult1_Q30, mult2Q + 30 ); |
| 70 | |
| 71 | /* Update inverse gain */ |
| 72 | /* invGain_Q30 range: [ 0 : 2^30 ] */ |
| 73 | invGain_Q30 = silk_LSHIFT( silk_SMMUL( invGain_Q30, rc_mult1_Q30 ), 2 ); |
| 74 | silk_assert( invGain_Q30 >= 0 ); |
| 75 | silk_assert( invGain_Q30 <= ( 1 << 30 ) ); |
| 76 | |
| 77 | /* Swap pointers */ |
| 78 | Aold_QA = Anew_QA; |
| 79 | Anew_QA = A_QA[ k & 1 ]; |
| 80 | |
| 81 | /* Update AR coefficient */ |
| 82 | for( n = 0; n < k; n++ ) { |
| 83 | tmp_QA = Aold_QA[ n ] - MUL32_FRAC_Q( Aold_QA[ k - n - 1 ], rc_Q31, 31 ); |
| 84 | Anew_QA[ n ] = MUL32_FRAC_Q( tmp_QA, rc_mult2 , mult2Q ); |
| 85 | } |
| 86 | } |
| 87 | |
| 88 | /* Check for stability */ |
| 89 | if( ( Anew_QA[ 0 ] > A_LIMIT ) || ( Anew_QA[ 0 ] < -A_LIMIT ) ) { |
| 90 | return 0; |
| 91 | } |
| 92 | |
| 93 | /* Set RC equal to negated AR coef */ |
| 94 | rc_Q31 = -silk_LSHIFT( Anew_QA[ 0 ], 31 - QA ); |
| 95 | |
| 96 | /* Range: [ 1 : 2^30 ] */ |
| 97 | rc_mult1_Q30 = ( (opus_int32)1 << 30 ) - silk_SMMUL( rc_Q31, rc_Q31 ); |
| 98 | |
| 99 | /* Update inverse gain */ |
| 100 | /* Range: [ 0 : 2^30 ] */ |
| 101 | invGain_Q30 = silk_LSHIFT( silk_SMMUL( invGain_Q30, rc_mult1_Q30 ), 2 ); |
| 102 | silk_assert( invGain_Q30 >= 0 ); |
| 103 | silk_assert( invGain_Q30 <= 1<<30 ); |
| 104 | |
| 105 | return invGain_Q30; |
| 106 | } |
| 107 | |
| 108 | /* For input in Q12 domain */ |
| 109 | opus_int32 silk_LPC_inverse_pred_gain( /* O Returns inverse prediction gain in energy domain, Q30 */ |
| 110 | const opus_int16 *A_Q12, /* I Prediction coefficients, Q12 [order] */ |
| 111 | const opus_int order /* I Prediction order */ |
| 112 | ) |
| 113 | { |
| 114 | opus_int k; |
| 115 | opus_int32 Atmp_QA[ 2 ][ SILK_MAX_ORDER_LPC ]; |
| 116 | opus_int32 *Anew_QA; |
| 117 | opus_int32 DC_resp = 0; |
| 118 | |
| 119 | Anew_QA = Atmp_QA[ order & 1 ]; |
| 120 | |
| 121 | /* Increase Q domain of the AR coefficients */ |
| 122 | for( k = 0; k < order; k++ ) { |
| 123 | DC_resp += (opus_int32)A_Q12[ k ]; |
| 124 | Anew_QA[ k ] = silk_LSHIFT32( (opus_int32)A_Q12[ k ], QA - 12 ); |
| 125 | } |
| 126 | /* If the DC is unstable, we don't even need to do the full calculations */ |
| 127 | if( DC_resp >= 4096 ) { |
| 128 | return 0; |
| 129 | } |
| 130 | return LPC_inverse_pred_gain_QA( Atmp_QA, order ); |
| 131 | } |
| 132 | |
| 133 | #ifdef FIXED_POINT |
| 134 | |
| 135 | /* For input in Q24 domain */ |
| 136 | opus_int32 silk_LPC_inverse_pred_gain_Q24( /* O Returns inverse prediction gain in energy domain, Q30 */ |
| 137 | const opus_int32 *A_Q24, /* I Prediction coefficients [order] */ |
| 138 | const opus_int order /* I Prediction order */ |
| 139 | ) |
| 140 | { |
| 141 | opus_int k; |
| 142 | opus_int32 Atmp_QA[ 2 ][ SILK_MAX_ORDER_LPC ]; |
| 143 | opus_int32 *Anew_QA; |
| 144 | |
| 145 | Anew_QA = Atmp_QA[ order & 1 ]; |
| 146 | |
| 147 | /* Increase Q domain of the AR coefficients */ |
| 148 | for( k = 0; k < order; k++ ) { |
| 149 | Anew_QA[ k ] = silk_RSHIFT32( A_Q24[ k ], 24 - QA ); |
| 150 | } |
| 151 | |
| 152 | return LPC_inverse_pred_gain_QA( Atmp_QA, order ); |
| 153 | } |
| 154 | #endif |