ref: d84fa9fd6eb96202f5721ae3ce6410d1cbb19f96
dir: /silk/CNG.c/
/***********************************************************************
Copyright (c) 2006-2011, Skype Limited. All rights reserved.
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modification, (subject to the limitations in the disclaimer below)
are permitted provided that the following conditions are met:
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this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright
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documentation and/or other materials provided with the distribution.
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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,
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COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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***********************************************************************/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "main.h"
/* Generates excitation for CNG LPC synthesis */
static inline void silk_CNG_exc(
opus_int32 residual_Q10[], /* O CNG residual signal Q10 */
opus_int32 exc_buf_Q10[], /* I Random samples buffer Q10 */
opus_int32 Gain_Q16, /* I Gain to apply */
opus_int length, /* I Length */
opus_int32 *rand_seed /* I/O Seed to random index generator */
)
{
opus_int32 seed;
opus_int i, idx, exc_mask;
exc_mask = CNG_BUF_MASK_MAX;
while( exc_mask > length ) {
exc_mask = silk_RSHIFT( exc_mask, 1 );
}
seed = *rand_seed;
for( i = 0; i < length; i++ ) {
seed = silk_RAND( seed );
idx = ( opus_int )( silk_RSHIFT( seed, 24 ) & exc_mask );
silk_assert( idx >= 0 );
silk_assert( idx <= CNG_BUF_MASK_MAX );
residual_Q10[ i ] = ( opus_int16 )silk_SAT16( silk_SMULWW( exc_buf_Q10[ idx ], Gain_Q16 ) );
}
*rand_seed = seed;
}
void silk_CNG_Reset(
silk_decoder_state *psDec /* I/O Decoder state */
)
{
opus_int i, NLSF_step_Q15, NLSF_acc_Q15;
NLSF_step_Q15 = silk_DIV32_16( silk_int16_MAX, psDec->LPC_order + 1 );
NLSF_acc_Q15 = 0;
for( i = 0; i < psDec->LPC_order; i++ ) {
NLSF_acc_Q15 += NLSF_step_Q15;
psDec->sCNG.CNG_smth_NLSF_Q15[ i ] = NLSF_acc_Q15;
}
psDec->sCNG.CNG_smth_Gain_Q16 = 0;
psDec->sCNG.rand_seed = 3176576;
}
/* Updates CNG estimate, and applies the CNG when packet was lost */
void silk_CNG(
silk_decoder_state *psDec, /* I/O Decoder state */
silk_decoder_control *psDecCtrl, /* I/O Decoder control */
opus_int16 frame[], /* I/O Signal data */
opus_int length /* I Length of residual */
)
{
opus_int i, j, subfr;
opus_int32 sum_Q6, max_Gain_Q16;
opus_int16 A_Q12[ MAX_LPC_ORDER ];
opus_int32 CNG_sig_Q10[ MAX_FRAME_LENGTH + MAX_LPC_ORDER ];
silk_CNG_struct *psCNG = &psDec->sCNG;
if( psDec->fs_kHz != psCNG->fs_kHz ) {
/* Reset state */
silk_CNG_Reset( psDec );
psCNG->fs_kHz = psDec->fs_kHz;
}
if( psDec->lossCnt == 0 && psDec->prevSignalType == TYPE_NO_VOICE_ACTIVITY ) {
/* Update CNG parameters */
/* Smoothing of LSF's */
for( i = 0; i < psDec->LPC_order; i++ ) {
psCNG->CNG_smth_NLSF_Q15[ i ] += silk_SMULWB( psDec->prevNLSF_Q15[ i ] - psCNG->CNG_smth_NLSF_Q15[ i ], CNG_NLSF_SMTH_Q16 );
}
/* Find the subframe with the highest gain */
max_Gain_Q16 = 0;
subfr = 0;
for( i = 0; i < psDec->nb_subfr; i++ ) {
if( psDecCtrl->Gains_Q16[ i ] > max_Gain_Q16 ) {
max_Gain_Q16 = psDecCtrl->Gains_Q16[ i ];
subfr = i;
}
}
/* Update CNG excitation buffer with excitation from this subframe */
silk_memmove( &psCNG->CNG_exc_buf_Q10[ psDec->subfr_length ], psCNG->CNG_exc_buf_Q10, ( psDec->nb_subfr - 1 ) * psDec->subfr_length * sizeof( opus_int32 ) );
silk_memcpy( psCNG->CNG_exc_buf_Q10, &psDec->exc_Q10[ subfr * psDec->subfr_length ], psDec->subfr_length * sizeof( opus_int32 ) );
/* Smooth gains */
for( i = 0; i < psDec->nb_subfr; i++ ) {
psCNG->CNG_smth_Gain_Q16 += silk_SMULWB( psDecCtrl->Gains_Q16[ i ] - psCNG->CNG_smth_Gain_Q16, CNG_GAIN_SMTH_Q16 );
}
}
/* Add CNG when packet is lost or during DTX */
if( psDec->lossCnt ) {
/* Generate CNG excitation */
silk_CNG_exc( CNG_sig_Q10 + MAX_LPC_ORDER, psCNG->CNG_exc_buf_Q10, psCNG->CNG_smth_Gain_Q16, length, &psCNG->rand_seed );
/* Convert CNG NLSF to filter representation */
silk_NLSF2A( A_Q12, psCNG->CNG_smth_NLSF_Q15, psDec->LPC_order );
/* Generate CNG signal, by synthesis filtering */
silk_memcpy( CNG_sig_Q10, psCNG->CNG_synth_state, MAX_LPC_ORDER * sizeof( opus_int32 ) );
for( i = 0; i < length; i++ ) {
/* Partially unrolled */
sum_Q6 = silk_SMULWB( CNG_sig_Q10[ MAX_LPC_ORDER + i - 1 ], A_Q12[ 0 ] );
sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 2 ], A_Q12[ 1 ] );
sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 3 ], A_Q12[ 2 ] );
sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 4 ], A_Q12[ 3 ] );
sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 5 ], A_Q12[ 4 ] );
sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 6 ], A_Q12[ 5 ] );
sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 7 ], A_Q12[ 6 ] );
sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 8 ], A_Q12[ 7 ] );
sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 9 ], A_Q12[ 8 ] );
sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 10 ], A_Q12[ 9 ] );
for( j = 10; j < psDec->LPC_order; j++ ) {
sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - j - 1 ], A_Q12[ j ] );
}
/* Update states */
CNG_sig_Q10[ MAX_LPC_ORDER + i ] = silk_ADD_LSHIFT( CNG_sig_Q10[ MAX_LPC_ORDER + i ], sum_Q6, 4 );
frame[ i ] = silk_ADD_SAT16( frame[ i ], silk_RSHIFT_ROUND( sum_Q6, 6 ) );
}
silk_memcpy( psCNG->CNG_synth_state, &CNG_sig_Q10[ length ], MAX_LPC_ORDER * sizeof( opus_int32 ) );
} else {
silk_memset( psCNG->CNG_synth_state, 0, psDec->LPC_order * sizeof( opus_int32 ) );
}
}