shithub: opus

ref: bceb8e1532e9b69076ace2ee063433aff0dc32ca
dir: /silk/silk_NSQ_del_dec.c/

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/***********************************************************************
Copyright (c) 2006-2011, Skype Limited. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, (subject to the limitations in the disclaimer below)
are permitted provided that the following conditions are met:
- Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
- Neither the name of Skype Limited, nor the names of specific
contributors, may be used to endorse or promote products derived from
this software without specific prior written permission.
NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED
BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
***********************************************************************/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "silk_main.h"

typedef struct {
    opus_int32 sLPC_Q14[ MAX_FRAME_LENGTH / MAX_NB_SUBFR + NSQ_LPC_BUF_LENGTH ];
    opus_int32 RandState[ DECISION_DELAY ];
    opus_int32 Q_Q10[     DECISION_DELAY ];
    opus_int32 Xq_Q10[    DECISION_DELAY ];
    opus_int32 Pred_Q16[  DECISION_DELAY ];
    opus_int32 Shape_Q10[ DECISION_DELAY ];
    opus_int32 sAR2_Q14[ MAX_SHAPE_LPC_ORDER ];
    opus_int32 LF_AR_Q12;
    opus_int32 Seed;
    opus_int32 SeedInit;
    opus_int32 RD_Q10;
} NSQ_del_dec_struct;

typedef struct {
    opus_int32 Q_Q10;
    opus_int32 RD_Q10;
    opus_int32 xq_Q14;
    opus_int32 LF_AR_Q12;
    opus_int32 sLTP_shp_Q10;
    opus_int32 LPC_exc_Q16;
} NSQ_sample_struct;

static inline void silk_nsq_del_dec_scale_states(
    const silk_encoder_state *psEncC,               /* I    Encoder State                       */
    silk_nsq_state      *NSQ,                       /* I/O  NSQ state                           */
    NSQ_del_dec_struct  psDelDec[],                 /* I/O  Delayed decision states             */
    const opus_int16     x[],                        /* I    Input in Q0                         */
    opus_int32           x_sc_Q10[],                 /* O    Input scaled with 1/Gain in Q10     */
    const opus_int16     sLTP[],                     /* I    Re-whitened LTP state in Q0         */
    opus_int32           sLTP_Q16[],                 /* O    LTP state matching scaled input     */
    opus_int             subfr,                      /* I    Subframe number                     */
    opus_int             nStatesDelayedDecision,     /* I    Number of del dec states            */
    opus_int             smpl_buf_idx,               /* I    Index to newest samples in buffers  */
    const opus_int       LTP_scale_Q14,              /* I    LTP state scaling                   */
    const opus_int32     Gains_Q16[ MAX_NB_SUBFR ],  /* I                                        */
    const opus_int       pitchL[ MAX_NB_SUBFR ]      /* I    Pitch lag                           */
);

/******************************************/
/* Noise shape quantizer for one subframe */
/******************************************/
static inline void silk_noise_shape_quantizer_del_dec(
    silk_nsq_state      *NSQ,                   /* I/O  NSQ state                           */
    NSQ_del_dec_struct  psDelDec[],             /* I/O  Delayed decision states             */
    opus_int             signalType,             /* I    Signal type                         */
    const opus_int32     x_Q10[],                /* I                                        */
    opus_int8            pulses[],               /* O                                        */
    opus_int16           xq[],                   /* O                                        */
    opus_int32           sLTP_Q16[],             /* I/O  LTP filter state                    */
    opus_int32           delayedGain_Q16[],      /* I/O  Gain delay buffer                   */
    const opus_int16     a_Q12[],                /* I    Short term prediction coefs         */
    const opus_int16     b_Q14[],                /* I    Long term prediction coefs          */
    const opus_int16     AR_shp_Q13[],           /* I    Noise shaping coefs                 */
    opus_int             lag,                    /* I    Pitch lag                           */
    opus_int32           HarmShapeFIRPacked_Q14, /* I                                        */
    opus_int             Tilt_Q14,               /* I    Spectral tilt                       */
    opus_int32           LF_shp_Q14,             /* I                                        */
    opus_int32           Gain_Q16,               /* I                                        */
    opus_int             Lambda_Q10,             /* I                                        */
    opus_int             offset_Q10,             /* I                                        */
    opus_int             length,                 /* I    Input length                        */
    opus_int             subfr,                  /* I    Subframe number                     */
    opus_int             shapingLPCOrder,        /* I    Shaping LPC filter order            */
    opus_int             predictLPCOrder,        /* I    Prediction filter order             */
    opus_int             warping_Q16,            /* I                                        */
    opus_int             nStatesDelayedDecision, /* I    Number of states in decision tree   */
    opus_int             *smpl_buf_idx,          /* I    Index to newest samples in buffers  */
    opus_int             decisionDelay           /* I                                        */
);

void silk_NSQ_del_dec(
    const silk_encoder_state        *psEncC,                                    /* I/O  Encoder State                       */
    silk_nsq_state                  *NSQ,                                       /* I/O  NSQ state                           */
    SideInfoIndices                 *psIndices,                                 /* I/O  Quantization Indices                */
    const opus_int16                 x[],                                        /* I    Prefiltered input signal            */
    opus_int8                        pulses[],                                   /* O    Quantized pulse signal              */
    const opus_int16                 PredCoef_Q12[ 2 * MAX_LPC_ORDER ],          /* I    Prediction coefs                    */
    const opus_int16                 LTPCoef_Q14[ LTP_ORDER * MAX_NB_SUBFR ],    /* I    LT prediction coefs                 */
    const opus_int16                 AR2_Q13[ MAX_NB_SUBFR * MAX_SHAPE_LPC_ORDER ], /* I                                     */
    const opus_int                   HarmShapeGain_Q14[ MAX_NB_SUBFR ],          /* I                                        */
    const opus_int                   Tilt_Q14[ MAX_NB_SUBFR ],                   /* I    Spectral tilt                       */
    const opus_int32                 LF_shp_Q14[ MAX_NB_SUBFR ],                 /* I                                        */
    const opus_int32                 Gains_Q16[ MAX_NB_SUBFR ],                  /* I                                        */
    const opus_int                   pitchL[ MAX_NB_SUBFR ],                     /* I                                        */
    const opus_int                   Lambda_Q10,                                 /* I                                        */
    const opus_int                   LTP_scale_Q14                               /* I    LTP state scaling                   */
)
{
    opus_int     i, k, lag, start_idx, LSF_interpolation_flag, Winner_ind, subfr;
    opus_int     last_smple_idx, smpl_buf_idx, decisionDelay;
    const opus_int16 *A_Q12, *B_Q14, *AR_shp_Q13;
    opus_int16   *pxq;
    opus_int32   sLTP_Q16[ 2 * MAX_FRAME_LENGTH ];
    opus_int16   sLTP[     2 * MAX_FRAME_LENGTH ];
    opus_int32   HarmShapeFIRPacked_Q14;
    opus_int     offset_Q10;
    opus_int32   RDmin_Q10;
    opus_int32   x_sc_Q10[ MAX_SUB_FRAME_LENGTH ];
    opus_int32   delayedGain_Q16[  DECISION_DELAY ];
    NSQ_del_dec_struct psDelDec[ MAX_DEL_DEC_STATES ];
    NSQ_del_dec_struct *psDD;

    /* Set unvoiced lag to the previous one, overwrite later for voiced */
    lag = NSQ->lagPrev;

    SKP_assert( NSQ->prev_inv_gain_Q16 != 0 );

    /* Initialize delayed decision states */
    SKP_memset( psDelDec, 0, psEncC->nStatesDelayedDecision * sizeof( NSQ_del_dec_struct ) );
    for( k = 0; k < psEncC->nStatesDelayedDecision; k++ ) {
        psDD                 = &psDelDec[ k ];
        psDD->Seed           = ( k + psIndices->Seed ) & 3;
        psDD->SeedInit       = psDD->Seed;
        psDD->RD_Q10         = 0;
        psDD->LF_AR_Q12      = NSQ->sLF_AR_shp_Q12;
        psDD->Shape_Q10[ 0 ] = NSQ->sLTP_shp_Q10[ psEncC->ltp_mem_length - 1 ];
        SKP_memcpy( psDD->sLPC_Q14, NSQ->sLPC_Q14, NSQ_LPC_BUF_LENGTH * sizeof( opus_int32 ) );
        SKP_memcpy( psDD->sAR2_Q14, NSQ->sAR2_Q14, sizeof( NSQ->sAR2_Q14 ) );
    }

    offset_Q10   = silk_Quantization_Offsets_Q10[ psIndices->signalType >> 1 ][ psIndices->quantOffsetType ];
    smpl_buf_idx = 0; /* index of oldest samples */

    decisionDelay = SKP_min_int( DECISION_DELAY, psEncC->subfr_length );

    /* For voiced frames limit the decision delay to lower than the pitch lag */
    if( psIndices->signalType == TYPE_VOICED ) {
        for( k = 0; k < psEncC->nb_subfr; k++ ) {
            decisionDelay = SKP_min_int( decisionDelay, pitchL[ k ] - LTP_ORDER / 2 - 1 );
        }
    } else {
        if( lag > 0 ) {
            decisionDelay = SKP_min_int( decisionDelay, lag - LTP_ORDER / 2 - 1 );
        }
    }

    if( psIndices->NLSFInterpCoef_Q2 == 4 ) {
        LSF_interpolation_flag = 0;
    } else {
        LSF_interpolation_flag = 1;
    }

    /* Setup pointers to start of sub frame */
    pxq                   = &NSQ->xq[ psEncC->ltp_mem_length ];
    NSQ->sLTP_shp_buf_idx = psEncC->ltp_mem_length;
    NSQ->sLTP_buf_idx     = psEncC->ltp_mem_length;
    subfr = 0;
    for( k = 0; k < psEncC->nb_subfr; k++ ) {
        A_Q12      = &PredCoef_Q12[ ( ( k >> 1 ) | ( 1 - LSF_interpolation_flag ) ) * MAX_LPC_ORDER ];
        B_Q14      = &LTPCoef_Q14[ k * LTP_ORDER           ];
        AR_shp_Q13 = &AR2_Q13[     k * MAX_SHAPE_LPC_ORDER ];

        /* Noise shape parameters */
        SKP_assert( HarmShapeGain_Q14[ k ] >= 0 );
        HarmShapeFIRPacked_Q14  =                          SKP_RSHIFT( HarmShapeGain_Q14[ k ], 2 );
        HarmShapeFIRPacked_Q14 |= SKP_LSHIFT( ( opus_int32 )SKP_RSHIFT( HarmShapeGain_Q14[ k ], 1 ), 16 );

        NSQ->rewhite_flag = 0;
        if( psIndices->signalType == TYPE_VOICED ) {
            /* Voiced */
            lag = pitchL[ k ];

            /* Re-whitening */
            if( ( k & ( 3 - SKP_LSHIFT( LSF_interpolation_flag, 1 ) ) ) == 0 ) {
                if( k == 2 ) {
                    /* RESET DELAYED DECISIONS */
                    /* Find winner */
                    RDmin_Q10 = psDelDec[ 0 ].RD_Q10;
                    Winner_ind = 0;
                    for( i = 1; i < psEncC->nStatesDelayedDecision; i++ ) {
                        if( psDelDec[ i ].RD_Q10 < RDmin_Q10 ) {
                            RDmin_Q10 = psDelDec[ i ].RD_Q10;
                            Winner_ind = i;
                        }
                    }
                    for( i = 0; i < psEncC->nStatesDelayedDecision; i++ ) {
                        if( i != Winner_ind ) {
                            psDelDec[ i ].RD_Q10 += ( SKP_int32_MAX >> 4 );
                            SKP_assert( psDelDec[ i ].RD_Q10 >= 0 );
                        }
                    }

                    /* Copy final part of signals from winner state to output and long-term filter states */
                    psDD = &psDelDec[ Winner_ind ];
                    last_smple_idx = smpl_buf_idx + decisionDelay;
                    for( i = 0; i < decisionDelay; i++ ) {
                        last_smple_idx = ( last_smple_idx - 1 ) & DECISION_DELAY_MASK;
                        pulses[   i - decisionDelay ] = ( opus_int8 )SKP_RSHIFT_ROUND( psDD->Q_Q10[ last_smple_idx ], 10 );
                        pxq[ i - decisionDelay ] = ( opus_int16 )SKP_SAT16( SKP_RSHIFT_ROUND(
                            SKP_SMULWW( psDD->Xq_Q10[ last_smple_idx ], Gains_Q16[ 1 ] ), 10 ) );
                        NSQ->sLTP_shp_Q10[ NSQ->sLTP_shp_buf_idx - decisionDelay + i ] = psDD->Shape_Q10[ last_smple_idx ];
                    }

                    subfr = 0;
                }

                /* Rewhiten with new A coefs */
                start_idx = psEncC->ltp_mem_length - lag - psEncC->predictLPCOrder - LTP_ORDER / 2;
                SKP_assert( start_idx > 0 );

                silk_LPC_analysis_filter( &sLTP[ start_idx ], &NSQ->xq[ start_idx + k * psEncC->subfr_length ],
                    A_Q12, psEncC->ltp_mem_length - start_idx, psEncC->predictLPCOrder );

                NSQ->sLTP_buf_idx = psEncC->ltp_mem_length;
                NSQ->rewhite_flag = 1;
            }
        }

        silk_nsq_del_dec_scale_states( psEncC, NSQ, psDelDec, x, x_sc_Q10, sLTP, sLTP_Q16, k,
            psEncC->nStatesDelayedDecision, smpl_buf_idx, LTP_scale_Q14, Gains_Q16, pitchL );

        silk_noise_shape_quantizer_del_dec( NSQ, psDelDec, psIndices->signalType, x_sc_Q10, pulses, pxq, sLTP_Q16,
            delayedGain_Q16, A_Q12, B_Q14, AR_shp_Q13, lag, HarmShapeFIRPacked_Q14, Tilt_Q14[ k ], LF_shp_Q14[ k ],
            Gains_Q16[ k ], Lambda_Q10, offset_Q10, psEncC->subfr_length, subfr++, psEncC->shapingLPCOrder,
            psEncC->predictLPCOrder, psEncC->warping_Q16, psEncC->nStatesDelayedDecision, &smpl_buf_idx, decisionDelay );

        x      += psEncC->subfr_length;
        pulses += psEncC->subfr_length;
        pxq    += psEncC->subfr_length;
    }

    /* Find winner */
    RDmin_Q10 = psDelDec[ 0 ].RD_Q10;
    Winner_ind = 0;
    for( k = 1; k < psEncC->nStatesDelayedDecision; k++ ) {
        if( psDelDec[ k ].RD_Q10 < RDmin_Q10 ) {
            RDmin_Q10 = psDelDec[ k ].RD_Q10;
            Winner_ind = k;
        }
    }

    /* Copy final part of signals from winner state to output and long-term filter states */
    psDD = &psDelDec[ Winner_ind ];
    psIndices->Seed = psDD->SeedInit;
    last_smple_idx = smpl_buf_idx + decisionDelay;
    for( i = 0; i < decisionDelay; i++ ) {
        last_smple_idx = ( last_smple_idx - 1 ) & DECISION_DELAY_MASK;
        pulses[   i - decisionDelay ] = ( opus_int8 )SKP_RSHIFT_ROUND( psDD->Q_Q10[ last_smple_idx ], 10 );
        pxq[ i - decisionDelay ] = ( opus_int16 )SKP_SAT16( SKP_RSHIFT_ROUND(
            SKP_SMULWW( psDD->Xq_Q10[ last_smple_idx ], Gains_Q16[ psEncC->nb_subfr - 1 ] ), 10 ) );
        NSQ->sLTP_shp_Q10[ NSQ->sLTP_shp_buf_idx - decisionDelay + i ] = psDD->Shape_Q10[ last_smple_idx ];
        sLTP_Q16[          NSQ->sLTP_buf_idx     - decisionDelay + i ] = psDD->Pred_Q16[  last_smple_idx ];
    }
    SKP_memcpy( NSQ->sLPC_Q14, &psDD->sLPC_Q14[ psEncC->subfr_length ], NSQ_LPC_BUF_LENGTH * sizeof( opus_int32 ) );
    SKP_memcpy( NSQ->sAR2_Q14, psDD->sAR2_Q14, sizeof( psDD->sAR2_Q14 ) );

    /* Update states */
    NSQ->sLF_AR_shp_Q12 = psDD->LF_AR_Q12;
    NSQ->lagPrev        = pitchL[ psEncC->nb_subfr - 1 ];

    /* Save quantized speech and noise shaping signals */
    SKP_memmove( NSQ->xq,           &NSQ->xq[           psEncC->frame_length ], psEncC->ltp_mem_length * sizeof( opus_int16 ) );
    SKP_memmove( NSQ->sLTP_shp_Q10, &NSQ->sLTP_shp_Q10[ psEncC->frame_length ], psEncC->ltp_mem_length * sizeof( opus_int32 ) );

#ifdef SAVE_ALL_INTERNAL_DATA
    DEBUG_STORE_DATA( xq.dat,       &pxq[ -psEncC->frame_length ],       psEncC->frame_length * sizeof( opus_int16 ) );
    DEBUG_STORE_DATA( q.dat,        &pulses[ -psEncC->frame_length ],    psEncC->frame_length * sizeof( opus_int8 ) );
    DEBUG_STORE_DATA( sLTP_Q16.dat, &sLTP_Q16[ psEncC->ltp_mem_length ], psEncC->frame_length * sizeof( opus_int32 ) );
#endif
}

/******************************************/
/* Noise shape quantizer for one subframe */
/******************************************/
static inline void silk_noise_shape_quantizer_del_dec(
    silk_nsq_state  *NSQ,                   /* I/O  NSQ state                           */
    NSQ_del_dec_struct  psDelDec[],             /* I/O  Delayed decision states             */
    opus_int             signalType,             /* I    Signal type                         */
    const opus_int32     x_Q10[],                /* I                                        */
    opus_int8            pulses[],               /* O                                        */
    opus_int16           xq[],                   /* O                                        */
    opus_int32           sLTP_Q16[],             /* I/O  LTP filter state                    */
    opus_int32           delayedGain_Q16[],      /* I/O  Gain delay buffer                   */
    const opus_int16     a_Q12[],                /* I    Short term prediction coefs         */
    const opus_int16     b_Q14[],                /* I    Long term prediction coefs          */
    const opus_int16     AR_shp_Q13[],           /* I    Noise shaping coefs                 */
    opus_int             lag,                    /* I    Pitch lag                           */
    opus_int32           HarmShapeFIRPacked_Q14, /* I                                        */
    opus_int             Tilt_Q14,               /* I    Spectral tilt                       */
    opus_int32           LF_shp_Q14,             /* I                                        */
    opus_int32           Gain_Q16,               /* I                                        */
    opus_int             Lambda_Q10,             /* I                                        */
    opus_int             offset_Q10,             /* I                                        */
    opus_int             length,                 /* I    Input length                        */
    opus_int             subfr,                  /* I    Subframe number                     */
    opus_int             shapingLPCOrder,        /* I    Shaping LPC filter order            */
    opus_int             predictLPCOrder,        /* I    Prediction filter order             */
    opus_int             warping_Q16,            /* I                                        */
    opus_int             nStatesDelayedDecision, /* I    Number of states in decision tree   */
    opus_int             *smpl_buf_idx,          /* I    Index to newest samples in buffers  */
    opus_int             decisionDelay           /* I                                        */
)
{
    opus_int     i, j, k, Winner_ind, RDmin_ind, RDmax_ind, last_smple_idx;
    opus_int32   Winner_rand_state;
    opus_int32   LTP_pred_Q14, LPC_pred_Q10, n_AR_Q10, n_LTP_Q14, LTP_Q10;
    opus_int32   n_LF_Q10, r_Q10, rr_Q10, rd1_Q10, rd2_Q10, RDmin_Q10, RDmax_Q10;
    opus_int32   q1_Q10, q2_Q10, dither, exc_Q10, LPC_exc_Q10, xq_Q10;
    opus_int32   tmp1, tmp2, sLF_AR_shp_Q10;
    opus_int32   *pred_lag_ptr, *shp_lag_ptr, *psLPC_Q14;
    NSQ_sample_struct  psSampleState[ MAX_DEL_DEC_STATES ][ 2 ];
    NSQ_del_dec_struct *psDD;
    NSQ_sample_struct  *psSS;

    shp_lag_ptr  = &NSQ->sLTP_shp_Q10[ NSQ->sLTP_shp_buf_idx - lag + HARM_SHAPE_FIR_TAPS / 2 ];
    pred_lag_ptr = &sLTP_Q16[ NSQ->sLTP_buf_idx - lag + LTP_ORDER / 2 ];

    for( i = 0; i < length; i++ ) {
        /* Perform common calculations used in all states */

        /* Long-term prediction */
        if( signalType == TYPE_VOICED ) {
            /* Unrolled loop */
            LTP_pred_Q14 = SKP_SMULWB(               pred_lag_ptr[  0 ], b_Q14[ 0 ] );
            LTP_pred_Q14 = SKP_SMLAWB( LTP_pred_Q14, pred_lag_ptr[ -1 ], b_Q14[ 1 ] );
            LTP_pred_Q14 = SKP_SMLAWB( LTP_pred_Q14, pred_lag_ptr[ -2 ], b_Q14[ 2 ] );
            LTP_pred_Q14 = SKP_SMLAWB( LTP_pred_Q14, pred_lag_ptr[ -3 ], b_Q14[ 3 ] );
            LTP_pred_Q14 = SKP_SMLAWB( LTP_pred_Q14, pred_lag_ptr[ -4 ], b_Q14[ 4 ] );
            pred_lag_ptr++;
        } else {
            LTP_pred_Q14 = 0;
        }

        /* Long-term shaping */
        if( lag > 0 ) {
            /* Symmetric, packed FIR coefficients */
            n_LTP_Q14 = SKP_SMULWB( SKP_ADD32( shp_lag_ptr[ 0 ], shp_lag_ptr[ -2 ] ), HarmShapeFIRPacked_Q14 );
            n_LTP_Q14 = SKP_SMLAWT( n_LTP_Q14, shp_lag_ptr[ -1 ],                     HarmShapeFIRPacked_Q14 );
            n_LTP_Q14 = SKP_LSHIFT( n_LTP_Q14, 6 );
            shp_lag_ptr++;

            LTP_Q10 = SKP_RSHIFT( SKP_SUB32( LTP_pred_Q14, n_LTP_Q14 ), 4 );
        } else {
            LTP_Q10 = 0;
        }

        for( k = 0; k < nStatesDelayedDecision; k++ ) {
            /* Delayed decision state */
            psDD = &psDelDec[ k ];

            /* Sample state */
            psSS = psSampleState[ k ];

            /* Generate dither */
            psDD->Seed = SKP_RAND( psDD->Seed );

            /* dither = rand_seed < 0 ? 0xFFFFFFFF : 0; */
            dither = SKP_RSHIFT( psDD->Seed, 31 );

            /* Pointer used in short term prediction and shaping */
            psLPC_Q14 = &psDD->sLPC_Q14[ NSQ_LPC_BUF_LENGTH - 1 + i ];
            /* Short-term prediction */
            SKP_assert( predictLPCOrder >= 10 );            /* check that unrolling works */
            SKP_assert( ( predictLPCOrder  & 1 ) == 0 );    /* check that order is even */
            SKP_assert( ( (opus_int64)a_Q12 & 3 ) == 0 );    /* check that array starts at 4-byte aligned address */
            /* Partially unrolled */
            LPC_pred_Q10 = SKP_SMULWB(               psLPC_Q14[  0 ], a_Q12[ 0 ] );
            LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -1 ], a_Q12[ 1 ] );
            LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -2 ], a_Q12[ 2 ] );
            LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -3 ], a_Q12[ 3 ] );
            LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -4 ], a_Q12[ 4 ] );
            LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -5 ], a_Q12[ 5 ] );
            LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -6 ], a_Q12[ 6 ] );
            LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -7 ], a_Q12[ 7 ] );
            LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -8 ], a_Q12[ 8 ] );
            LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -9 ], a_Q12[ 9 ] );
            for( j = 10; j < predictLPCOrder; j ++ ) {
                LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -j ], a_Q12[ j ] );
            }

            /* Noise shape feedback */
            SKP_assert( ( shapingLPCOrder & 1 ) == 0 );   /* check that order is even */
            /* Output of lowpass section */
            tmp2 = SKP_SMLAWB( psLPC_Q14[ 0 ], psDD->sAR2_Q14[ 0 ], warping_Q16 );
            /* Output of allpass section */
            tmp1 = SKP_SMLAWB( psDD->sAR2_Q14[ 0 ], psDD->sAR2_Q14[ 1 ] - tmp2, warping_Q16 );
            psDD->sAR2_Q14[ 0 ] = tmp2;
            n_AR_Q10 = SKP_SMULWB( tmp2, AR_shp_Q13[ 0 ] );
            /* Loop over allpass sections */
            for( j = 2; j < shapingLPCOrder; j += 2 ) {
                /* Output of allpass section */
                tmp2 = SKP_SMLAWB( psDD->sAR2_Q14[ j - 1 ], psDD->sAR2_Q14[ j + 0 ] - tmp1, warping_Q16 );
                psDD->sAR2_Q14[ j - 1 ] = tmp1;
                n_AR_Q10 = SKP_SMLAWB( n_AR_Q10, tmp1, AR_shp_Q13[ j - 1 ] );
                /* Output of allpass section */
                tmp1 = SKP_SMLAWB( psDD->sAR2_Q14[ j + 0 ], psDD->sAR2_Q14[ j + 1 ] - tmp2, warping_Q16 );
                psDD->sAR2_Q14[ j + 0 ] = tmp2;
                n_AR_Q10 = SKP_SMLAWB( n_AR_Q10, tmp2, AR_shp_Q13[ j ] );
            }
            psDD->sAR2_Q14[ shapingLPCOrder - 1 ] = tmp1;
            n_AR_Q10 = SKP_SMLAWB( n_AR_Q10, tmp1, AR_shp_Q13[ shapingLPCOrder - 1 ] );

            n_AR_Q10 = SKP_RSHIFT( n_AR_Q10, 1 );           /* Q11 -> Q10 */
            n_AR_Q10 = SKP_SMLAWB( n_AR_Q10, psDD->LF_AR_Q12, Tilt_Q14 );

            n_LF_Q10 = SKP_LSHIFT( SKP_SMULWB( psDD->Shape_Q10[ *smpl_buf_idx ], LF_shp_Q14 ), 2 );
            n_LF_Q10 = SKP_SMLAWT( n_LF_Q10, psDD->LF_AR_Q12, LF_shp_Q14 );

            /* Input minus prediction plus noise feedback                       */
            /* r = x[ i ] - LTP_pred - LPC_pred + n_AR + n_Tilt + n_LF + n_LTP  */
            tmp1  = SKP_ADD32( LTP_Q10, LPC_pred_Q10 );                         /* add Q10 stuff */
            tmp1  = SKP_SUB32( tmp1, n_AR_Q10 );                                /* subtract Q10 stuff */
            tmp1  = SKP_SUB32( tmp1, n_LF_Q10 );                                /* subtract Q10 stuff */
            r_Q10 = SKP_SUB32( x_Q10[ i ], tmp1 );                              /* residual error Q10 */

            /* Flip sign depending on dither */
            r_Q10 = r_Q10 ^ dither;
            r_Q10 = SKP_LIMIT_32( r_Q10, -31 << 10, 30 << 10 );

            /* Find two quantization level candidates and measure their rate-distortion */
            q1_Q10 = SKP_SUB32( r_Q10, offset_Q10 );
            q1_Q10 = SKP_RSHIFT( q1_Q10, 10 );
            if( q1_Q10 > 0 ) {
                q1_Q10  = SKP_SUB32( SKP_LSHIFT( q1_Q10, 10 ), QUANT_LEVEL_ADJUST_Q10 );
                q1_Q10  = SKP_ADD32( q1_Q10, offset_Q10 );
                q2_Q10  = SKP_ADD32( q1_Q10, 1024 );
                rd1_Q10 = SKP_SMULBB( q1_Q10, Lambda_Q10 );
                rd2_Q10 = SKP_SMULBB( q2_Q10, Lambda_Q10 );
            } else if( q1_Q10 == 0 ) {
                q1_Q10  = offset_Q10;
                q2_Q10  = SKP_ADD32( q1_Q10, 1024 - QUANT_LEVEL_ADJUST_Q10 );
                rd1_Q10 = SKP_SMULBB( q1_Q10, Lambda_Q10 );
                rd2_Q10 = SKP_SMULBB( q2_Q10, Lambda_Q10 );
            } else if( q1_Q10 == -1 ) {
                q2_Q10  = offset_Q10;
                q1_Q10  = SKP_SUB32( q2_Q10, 1024 - QUANT_LEVEL_ADJUST_Q10 );
                rd1_Q10 = SKP_SMULBB( -q1_Q10, Lambda_Q10 );
                rd2_Q10 = SKP_SMULBB(  q2_Q10, Lambda_Q10 );
            } else {            /* Q1_Q10 < -1 */
                q1_Q10  = SKP_ADD32( SKP_LSHIFT( q1_Q10, 10 ), QUANT_LEVEL_ADJUST_Q10 );
                q1_Q10  = SKP_ADD32( q1_Q10, offset_Q10 );
                q2_Q10  = SKP_ADD32( q1_Q10, 1024 );
                rd1_Q10 = SKP_SMULBB( -q1_Q10, Lambda_Q10 );
                rd2_Q10 = SKP_SMULBB( -q2_Q10, Lambda_Q10 );
            }
            rr_Q10  = SKP_SUB32( r_Q10, q1_Q10 );
            rd1_Q10 = SKP_RSHIFT( SKP_SMLABB( rd1_Q10, rr_Q10, rr_Q10 ), 10 );
            rr_Q10  = SKP_SUB32( r_Q10, q2_Q10 );
            rd2_Q10 = SKP_RSHIFT( SKP_SMLABB( rd2_Q10, rr_Q10, rr_Q10 ), 10 );

            if( rd1_Q10 < rd2_Q10 ) {
                psSS[ 0 ].RD_Q10 = SKP_ADD32( psDD->RD_Q10, rd1_Q10 );
                psSS[ 1 ].RD_Q10 = SKP_ADD32( psDD->RD_Q10, rd2_Q10 );
                psSS[ 0 ].Q_Q10  = q1_Q10;
                psSS[ 1 ].Q_Q10  = q2_Q10;
            } else {
                psSS[ 0 ].RD_Q10 = SKP_ADD32( psDD->RD_Q10, rd2_Q10 );
                psSS[ 1 ].RD_Q10 = SKP_ADD32( psDD->RD_Q10, rd1_Q10 );
                psSS[ 0 ].Q_Q10  = q2_Q10;
                psSS[ 1 ].Q_Q10  = q1_Q10;
            }

            /* Update states for best quantization */

            /* Quantized excitation */
            exc_Q10 = psSS[ 0 ].Q_Q10 ^ dither;

            /* Add predictions */
            LPC_exc_Q10 = exc_Q10 + SKP_RSHIFT_ROUND( LTP_pred_Q14, 4 );
            xq_Q10      = SKP_ADD32( LPC_exc_Q10, LPC_pred_Q10 );

            /* Update states */
            sLF_AR_shp_Q10         = SKP_SUB32(  xq_Q10, n_AR_Q10 );
            psSS[ 0 ].sLTP_shp_Q10 = SKP_SUB32(  sLF_AR_shp_Q10, n_LF_Q10 );
            psSS[ 0 ].LF_AR_Q12    = SKP_LSHIFT( sLF_AR_shp_Q10, 2 );
            psSS[ 0 ].xq_Q14       = SKP_LSHIFT( xq_Q10,         4 );
            psSS[ 0 ].LPC_exc_Q16  = SKP_LSHIFT( LPC_exc_Q10,    6 );

            /* Update states for second best quantization */

            /* Quantized excitation */
            exc_Q10 = psSS[ 1 ].Q_Q10 ^ dither;

            /* Add predictions */
            LPC_exc_Q10 = exc_Q10 + SKP_RSHIFT_ROUND( LTP_pred_Q14, 4 );
            xq_Q10      = SKP_ADD32( LPC_exc_Q10, LPC_pred_Q10 );

            /* Update states */
            sLF_AR_shp_Q10         = SKP_SUB32(  xq_Q10, n_AR_Q10 );
            psSS[ 1 ].sLTP_shp_Q10 = SKP_SUB32(  sLF_AR_shp_Q10, n_LF_Q10 );
            psSS[ 1 ].LF_AR_Q12    = SKP_LSHIFT( sLF_AR_shp_Q10, 2 );
            psSS[ 1 ].xq_Q14       = SKP_LSHIFT( xq_Q10,         4 );
            psSS[ 1 ].LPC_exc_Q16  = SKP_LSHIFT( LPC_exc_Q10,    6 );
        }

        *smpl_buf_idx  = ( *smpl_buf_idx - 1 ) & DECISION_DELAY_MASK;                   /* Index to newest samples              */
        last_smple_idx = ( *smpl_buf_idx + decisionDelay ) & DECISION_DELAY_MASK;       /* Index to decisionDelay old samples   */

        /* Find winner */
        RDmin_Q10 = psSampleState[ 0 ][ 0 ].RD_Q10;
        Winner_ind = 0;
        for( k = 1; k < nStatesDelayedDecision; k++ ) {
            if( psSampleState[ k ][ 0 ].RD_Q10 < RDmin_Q10 ) {
                RDmin_Q10  = psSampleState[ k ][ 0 ].RD_Q10;
                Winner_ind = k;
            }
        }

        /* Increase RD values of expired states */
        Winner_rand_state = psDelDec[ Winner_ind ].RandState[ last_smple_idx ];
        for( k = 0; k < nStatesDelayedDecision; k++ ) {
            if( psDelDec[ k ].RandState[ last_smple_idx ] != Winner_rand_state ) {
                psSampleState[ k ][ 0 ].RD_Q10 = SKP_ADD32( psSampleState[ k ][ 0 ].RD_Q10, ( SKP_int32_MAX >> 4 ) );
                psSampleState[ k ][ 1 ].RD_Q10 = SKP_ADD32( psSampleState[ k ][ 1 ].RD_Q10, ( SKP_int32_MAX >> 4 ) );
                SKP_assert( psSampleState[ k ][ 0 ].RD_Q10 >= 0 );
            }
        }

        /* Find worst in first set and best in second set */
        RDmax_Q10  = psSampleState[ 0 ][ 0 ].RD_Q10;
        RDmin_Q10  = psSampleState[ 0 ][ 1 ].RD_Q10;
        RDmax_ind = 0;
        RDmin_ind = 0;
        for( k = 1; k < nStatesDelayedDecision; k++ ) {
            /* find worst in first set */
            if( psSampleState[ k ][ 0 ].RD_Q10 > RDmax_Q10 ) {
                RDmax_Q10  = psSampleState[ k ][ 0 ].RD_Q10;
                RDmax_ind = k;
            }
            /* find best in second set */
            if( psSampleState[ k ][ 1 ].RD_Q10 < RDmin_Q10 ) {
                RDmin_Q10  = psSampleState[ k ][ 1 ].RD_Q10;
                RDmin_ind = k;
            }
        }

        /* Replace a state if best from second set outperforms worst in first set */
        if( RDmin_Q10 < RDmax_Q10 ) {
            SKP_memcpy( ((opus_int32 *)&psDelDec[ RDmax_ind ]) + i,
                        ((opus_int32 *)&psDelDec[ RDmin_ind ]) + i, sizeof( NSQ_del_dec_struct ) - i * sizeof( opus_int32) );
            SKP_memcpy( &psSampleState[ RDmax_ind ][ 0 ], &psSampleState[ RDmin_ind ][ 1 ], sizeof( NSQ_sample_struct ) );
        }

        /* Write samples from winner to output and long-term filter states */
        psDD = &psDelDec[ Winner_ind ];
        if( subfr > 0 || i >= decisionDelay ) {
            pulses[  i - decisionDelay ] = ( opus_int8 )SKP_RSHIFT_ROUND( psDD->Q_Q10[ last_smple_idx ], 10 );
            xq[ i - decisionDelay ] = ( opus_int16 )SKP_SAT16( SKP_RSHIFT_ROUND(
                SKP_SMULWW( psDD->Xq_Q10[ last_smple_idx ], delayedGain_Q16[ last_smple_idx ] ), 10 ) );
            NSQ->sLTP_shp_Q10[ NSQ->sLTP_shp_buf_idx - decisionDelay ] = psDD->Shape_Q10[ last_smple_idx ];
            sLTP_Q16[          NSQ->sLTP_buf_idx     - decisionDelay ] = psDD->Pred_Q16[  last_smple_idx ];
        }
        NSQ->sLTP_shp_buf_idx++;
        NSQ->sLTP_buf_idx++;

        /* Update states */
        for( k = 0; k < nStatesDelayedDecision; k++ ) {
            psDD                                     = &psDelDec[ k ];
            psSS                                     = &psSampleState[ k ][ 0 ];
            psDD->LF_AR_Q12                          = psSS->LF_AR_Q12;
            psDD->sLPC_Q14[ NSQ_LPC_BUF_LENGTH + i ] = psSS->xq_Q14;
            psDD->Xq_Q10[    *smpl_buf_idx ]         = SKP_RSHIFT( psSS->xq_Q14, 4 );
            psDD->Q_Q10[     *smpl_buf_idx ]         = psSS->Q_Q10;
            psDD->Pred_Q16[  *smpl_buf_idx ]         = psSS->LPC_exc_Q16;
            psDD->Shape_Q10[ *smpl_buf_idx ]         = psSS->sLTP_shp_Q10;
            psDD->Seed                               = SKP_ADD32( psDD->Seed, SKP_RSHIFT_ROUND( psSS->Q_Q10, 10 ) );
            psDD->RandState[ *smpl_buf_idx ]         = psDD->Seed;
            psDD->RD_Q10                             = psSS->RD_Q10;
        }
        delayedGain_Q16[     *smpl_buf_idx ]         = Gain_Q16;
    }
    /* Update LPC states */
    for( k = 0; k < nStatesDelayedDecision; k++ ) {
        psDD = &psDelDec[ k ];
        SKP_memcpy( psDD->sLPC_Q14, &psDD->sLPC_Q14[ length ], NSQ_LPC_BUF_LENGTH * sizeof( opus_int32 ) );
    }
}

static inline void silk_nsq_del_dec_scale_states(
    const silk_encoder_state *psEncC,               /* I    Encoder State                       */
    silk_nsq_state      *NSQ,                       /* I/O  NSQ state                           */
    NSQ_del_dec_struct  psDelDec[],                 /* I/O  Delayed decision states             */
    const opus_int16     x[],                        /* I    Input in Q0                         */
    opus_int32           x_sc_Q10[],                 /* O    Input scaled with 1/Gain in Q10     */
    const opus_int16     sLTP[],                     /* I    Re-whitened LTP state in Q0         */
    opus_int32           sLTP_Q16[],                 /* O    LTP state matching scaled input     */
    opus_int             subfr,                      /* I    Subframe number                     */
    opus_int             nStatesDelayedDecision,     /* I    Number of del dec states            */
    opus_int             smpl_buf_idx,               /* I    Index to newest samples in buffers  */
    const opus_int       LTP_scale_Q14,              /* I    LTP state scaling                   */
    const opus_int32     Gains_Q16[ MAX_NB_SUBFR ],  /* I                                        */
    const opus_int       pitchL[ MAX_NB_SUBFR ]      /* I    Pitch lag                           */
)
{
    opus_int            i, k, lag;
    opus_int32          inv_gain_Q16, gain_adj_Q16, inv_gain_Q32;
    NSQ_del_dec_struct *psDD;

    inv_gain_Q16 = silk_INVERSE32_varQ( SKP_max( Gains_Q16[ subfr ], 1 ), 32 );
    inv_gain_Q16 = SKP_min( inv_gain_Q16, SKP_int16_MAX );
    lag          = pitchL[ subfr ];

    /* After rewhitening the LTP state is un-scaled, so scale with inv_gain_Q16 */
    if( NSQ->rewhite_flag ) {
        inv_gain_Q32 = SKP_LSHIFT( inv_gain_Q16, 16 );
        if( subfr == 0 ) {
            /* Do LTP downscaling */
            inv_gain_Q32 = SKP_LSHIFT( SKP_SMULWB( inv_gain_Q32, LTP_scale_Q14 ), 2 );
        }
        for( i = NSQ->sLTP_buf_idx - lag - LTP_ORDER / 2; i < NSQ->sLTP_buf_idx; i++ ) {
            SKP_assert( i < MAX_FRAME_LENGTH );
            sLTP_Q16[ i ] = SKP_SMULWB( inv_gain_Q32, sLTP[ i ] );
        }
    }

    /* Adjust for changing gain */
    if( inv_gain_Q16 != NSQ->prev_inv_gain_Q16 ) {
        gain_adj_Q16 = silk_DIV32_varQ( inv_gain_Q16, NSQ->prev_inv_gain_Q16, 16 );

        /* Scale long-term shaping state */
        for( i = NSQ->sLTP_shp_buf_idx - psEncC->ltp_mem_length; i < NSQ->sLTP_shp_buf_idx; i++ ) {
            NSQ->sLTP_shp_Q10[ i ] = SKP_SMULWW( gain_adj_Q16, NSQ->sLTP_shp_Q10[ i ] );
        }

        /* Scale long-term prediction state */
        if( NSQ->rewhite_flag == 0 ) {
            for( i = NSQ->sLTP_buf_idx - lag - LTP_ORDER / 2; i < NSQ->sLTP_buf_idx; i++ ) {
                sLTP_Q16[ i ] = SKP_SMULWW( gain_adj_Q16, sLTP_Q16[ i ] );
            }
        }

        for( k = 0; k < nStatesDelayedDecision; k++ ) {
            psDD = &psDelDec[ k ];

            /* Scale scalar states */
            psDD->LF_AR_Q12 = SKP_SMULWW( gain_adj_Q16, psDD->LF_AR_Q12 );

            /* Scale short-term prediction and shaping states */
            for( i = 0; i < NSQ_LPC_BUF_LENGTH; i++ ) {
                psDD->sLPC_Q14[ i ] = SKP_SMULWW( gain_adj_Q16, psDD->sLPC_Q14[ i ] );
            }
            for( i = 0; i < MAX_SHAPE_LPC_ORDER; i++ ) {
                psDD->sAR2_Q14[ i ] = SKP_SMULWW( gain_adj_Q16, psDD->sAR2_Q14[ i ] );
            }
            for( i = 0; i < DECISION_DELAY; i++ ) {
                psDD->Pred_Q16[  i ] = SKP_SMULWW( gain_adj_Q16, psDD->Pred_Q16[  i ] );
                psDD->Shape_Q10[ i ] = SKP_SMULWW( gain_adj_Q16, psDD->Shape_Q10[ i ] );
            }
        }
    }

    /* Scale input */
    for( i = 0; i < psEncC->subfr_length; i++ ) {
        x_sc_Q10[ i ] = SKP_RSHIFT( SKP_SMULBB( x[ i ], ( opus_int16 )inv_gain_Q16 ), 6 );
    }

    /* save inv_gain */
    SKP_assert( inv_gain_Q16 != 0 );
    NSQ->prev_inv_gain_Q16 = inv_gain_Q16;
}