media/libopus/silk/CNG.c

   1 /***********************************************************************
   2 Copyright (c) 2006-2011, Skype Limited. All rights reserved.
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   4 modification, are permitted provided that the following conditions
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   9 notice, this list of conditions and the following disclaimer in the
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  11 - Neither the name of Internet Society, IETF or IETF Trust, nor the
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  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
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  18 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  19 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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  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 "main.h"
  33 #include "stack_alloc.h"
  34
  35 /* Generates excitation for CNG LPC synthesis */
  36 static OPUS_INLINE void silk_CNG_exc(
  37     opus_int32                       exc_Q14[],          /* O    CNG excitation signal Q10                   */
  38     opus_int32                       exc_buf_Q14[],      /* I    Random samples buffer Q10                   */
  39     opus_int                         length,             /* I    Length                                      */
  40     opus_int32                       *rand_seed          /* I/O  Seed to random index generator              */
  41 )
  42 {
  43     opus_int32 seed;
  44     opus_int   i, idx, exc_mask;
  45
  46     exc_mask = CNG_BUF_MASK_MAX;
  47     while( exc_mask > length ) {
  48         exc_mask = silk_RSHIFT( exc_mask, 1 );
  49     }
  50
  51     seed = *rand_seed;
  52     for( i = 0; i < length; i++ ) {
  53         seed = silk_RAND( seed );
  54         idx = (opus_int)( silk_RSHIFT( seed, 24 ) & exc_mask );
  55         silk_assert( idx >= 0 );
  56         silk_assert( idx <= CNG_BUF_MASK_MAX );
  57         exc_Q14[ i ] = exc_buf_Q14[ idx ];
  58     }
  59     *rand_seed = seed;
  60 }
  61
  62 void silk_CNG_Reset(
  63     silk_decoder_state          *psDec                          /* I/O  Decoder state                               */
  64 )
  65 {
  66     opus_int i, NLSF_step_Q15, NLSF_acc_Q15;
  67
  68     NLSF_step_Q15 = silk_DIV32_16( silk_int16_MAX, psDec->LPC_order + 1 );
  69     NLSF_acc_Q15 = 0;
  70     for( i = 0; i < psDec->LPC_order; i++ ) {
  71         NLSF_acc_Q15 += NLSF_step_Q15;
  72         psDec->sCNG.CNG_smth_NLSF_Q15[ i ] = NLSF_acc_Q15;
  73     }
  74     psDec->sCNG.CNG_smth_Gain_Q16 = 0;
  75     psDec->sCNG.rand_seed = 3176576;
  76 }
  77
  78 /* Updates CNG estimate, and applies the CNG when packet was lost   */
  79 void silk_CNG(
  80     silk_decoder_state          *psDec,                         /* I/O  Decoder state                               */
  81     silk_decoder_control        *psDecCtrl,                     /* I/O  Decoder control                             */
  82     opus_int16                  frame[],                        /* I/O  Signal                                      */
  83     opus_int                    length                          /* I    Length of residual                          */
  84 )
  85 {
  86     opus_int   i, subfr;
  87     opus_int32 LPC_pred_Q10, max_Gain_Q16, gain_Q16, gain_Q10;
  88     opus_int16 A_Q12[ MAX_LPC_ORDER ];
  89     silk_CNG_struct *psCNG = &psDec->sCNG;
  90     SAVE_STACK;
  91
  92     if( psDec->fs_kHz != psCNG->fs_kHz ) {
  93         /* Reset state */
  94         silk_CNG_Reset( psDec );
  95
  96         psCNG->fs_kHz = psDec->fs_kHz;
  97     }
  98     if( psDec->lossCnt == 0 && psDec->prevSignalType == TYPE_NO_VOICE_ACTIVITY ) {
  99         /* Update CNG parameters */
 100
 101         /* Smoothing of LSF's  */
 102         for( i = 0; i < psDec->LPC_order; i++ ) {
 103             psCNG->CNG_smth_NLSF_Q15[ i ] += silk_SMULWB( (opus_int32)psDec->prevNLSF_Q15[ i ] - (opus_int32)psCNG->CNG_smth_NLSF_Q15[ i ], CNG_NLSF_SMTH_Q16 );
 104         }
 105         /* Find the subframe with the highest gain */
 106         max_Gain_Q16 = 0;
 107         subfr        = 0;
 108         for( i = 0; i < psDec->nb_subfr; i++ ) {
 109             if( psDecCtrl->Gains_Q16[ i ] > max_Gain_Q16 ) {
 110                 max_Gain_Q16 = psDecCtrl->Gains_Q16[ i ];
 111                 subfr        = i;
 112             }
 113         }
 114         /* Update CNG excitation buffer with excitation from this subframe */
 115         silk_memmove( &psCNG->CNG_exc_buf_Q14[ psDec->subfr_length ], psCNG->CNG_exc_buf_Q14, ( psDec->nb_subfr - 1 ) * psDec->subfr_length * sizeof( opus_int32 ) );
 116         silk_memcpy(   psCNG->CNG_exc_buf_Q14, &psDec->exc_Q14[ subfr * psDec->subfr_length ], psDec->subfr_length * sizeof( opus_int32 ) );
 117
 118         /* Smooth gains */
 119         for( i = 0; i < psDec->nb_subfr; i++ ) {
 120             psCNG->CNG_smth_Gain_Q16 += silk_SMULWB( psDecCtrl->Gains_Q16[ i ] - psCNG->CNG_smth_Gain_Q16, CNG_GAIN_SMTH_Q16 );
 121             /* If the smoothed gain is 3 dB greater than this subframe's gain, use this subframe's gain to adapt faster. */
 122             if( silk_SMULWW( psCNG->CNG_smth_Gain_Q16, CNG_GAIN_SMTH_THRESHOLD_Q16 ) > psDecCtrl->Gains_Q16[ i ] ) {
 123                 psCNG->CNG_smth_Gain_Q16 = psDecCtrl->Gains_Q16[ i ];
 124             }
 125         }
 126     }
 127
 128     /* Add CNG when packet is lost or during DTX */
 129     if( psDec->lossCnt ) {
 130         VARDECL( opus_int32, CNG_sig_Q14 );
 131         ALLOC( CNG_sig_Q14, length + MAX_LPC_ORDER, opus_int32 );
 132
 133         /* Generate CNG excitation */
 134         gain_Q16 = silk_SMULWW( psDec->sPLC.randScale_Q14, psDec->sPLC.prevGain_Q16[1] );
 135         if( gain_Q16 >= (1 << 21) || psCNG->CNG_smth_Gain_Q16 > (1 << 23) ) {
 136             gain_Q16 = silk_SMULTT( gain_Q16, gain_Q16 );
 137             gain_Q16 = silk_SUB_LSHIFT32(silk_SMULTT( psCNG->CNG_smth_Gain_Q16, psCNG->CNG_smth_Gain_Q16 ), gain_Q16, 5 );
 138             gain_Q16 = silk_LSHIFT32( silk_SQRT_APPROX( gain_Q16 ), 16 );
 139         } else {
 140             gain_Q16 = silk_SMULWW( gain_Q16, gain_Q16 );
 141             gain_Q16 = silk_SUB_LSHIFT32(silk_SMULWW( psCNG->CNG_smth_Gain_Q16, psCNG->CNG_smth_Gain_Q16 ), gain_Q16, 5 );
 142             gain_Q16 = silk_LSHIFT32( silk_SQRT_APPROX( gain_Q16 ), 8 );
 143         }
 144         gain_Q10 = silk_RSHIFT( gain_Q16, 6 );
 145
 146         silk_CNG_exc( CNG_sig_Q14 + MAX_LPC_ORDER, psCNG->CNG_exc_buf_Q14, length, &psCNG->rand_seed );
 147
 148         /* Convert CNG NLSF to filter representation */
 149         silk_NLSF2A( A_Q12, psCNG->CNG_smth_NLSF_Q15, psDec->LPC_order, psDec->arch );
 150
 151         /* Generate CNG signal, by synthesis filtering */
 152         silk_memcpy( CNG_sig_Q14, psCNG->CNG_synth_state, MAX_LPC_ORDER * sizeof( opus_int32 ) );
 153         celt_assert( psDec->LPC_order == 10 || psDec->LPC_order == 16 );
 154         for( i = 0; i < length; i++ ) {
 155             /* Avoids introducing a bias because silk_SMLAWB() always rounds to -inf */
 156             LPC_pred_Q10 = silk_RSHIFT( psDec->LPC_order, 1 );
 157             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, CNG_sig_Q14[ MAX_LPC_ORDER + i -  1 ], A_Q12[ 0 ] );
 158             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, CNG_sig_Q14[ MAX_LPC_ORDER + i -  2 ], A_Q12[ 1 ] );
 159             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, CNG_sig_Q14[ MAX_LPC_ORDER + i -  3 ], A_Q12[ 2 ] );
 160             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, CNG_sig_Q14[ MAX_LPC_ORDER + i -  4 ], A_Q12[ 3 ] );
 161             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, CNG_sig_Q14[ MAX_LPC_ORDER + i -  5 ], A_Q12[ 4 ] );
 162             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, CNG_sig_Q14[ MAX_LPC_ORDER + i -  6 ], A_Q12[ 5 ] );
 163             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, CNG_sig_Q14[ MAX_LPC_ORDER + i -  7 ], A_Q12[ 6 ] );
 164             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, CNG_sig_Q14[ MAX_LPC_ORDER + i -  8 ], A_Q12[ 7 ] );
 165             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, CNG_sig_Q14[ MAX_LPC_ORDER + i -  9 ], A_Q12[ 8 ] );
 166             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, CNG_sig_Q14[ MAX_LPC_ORDER + i - 10 ], A_Q12[ 9 ] );
 167             if( psDec->LPC_order == 16 ) {
 168                 LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, CNG_sig_Q14[ MAX_LPC_ORDER + i - 11 ], A_Q12[ 10 ] );
 169                 LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, CNG_sig_Q14[ MAX_LPC_ORDER + i - 12 ], A_Q12[ 11 ] );
 170                 LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, CNG_sig_Q14[ MAX_LPC_ORDER + i - 13 ], A_Q12[ 12 ] );
 171                 LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, CNG_sig_Q14[ MAX_LPC_ORDER + i - 14 ], A_Q12[ 13 ] );
 172                 LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, CNG_sig_Q14[ MAX_LPC_ORDER + i - 15 ], A_Q12[ 14 ] );
 173                 LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, CNG_sig_Q14[ MAX_LPC_ORDER + i - 16 ], A_Q12[ 15 ] );
 174             }
 175
 176             /* Update states */
 177             CNG_sig_Q14[ MAX_LPC_ORDER + i ] = silk_ADD_SAT32( CNG_sig_Q14[ MAX_LPC_ORDER + i ], silk_LSHIFT_SAT32( LPC_pred_Q10, 4 ) );
 178
 179             /* Scale with Gain and add to input signal */
 180             frame[ i ] = (opus_int16)silk_ADD_SAT16( frame[ i ], silk_SAT16( silk_RSHIFT_ROUND( silk_SMULWW( CNG_sig_Q14[ MAX_LPC_ORDER + i ], gain_Q10 ), 8 ) ) );
 181
 182         }
 183         silk_memcpy( psCNG->CNG_synth_state, &CNG_sig_Q14[ length ], MAX_LPC_ORDER * sizeof( opus_int32 ) );
 184     } else {
 185         silk_memset( psCNG->CNG_synth_state, 0, psDec->LPC_order *  sizeof( opus_int32 ) );
 186     }
 187     RESTORE_STACK;
 188 }