ref: 5d7b03669cb067c8848dfad642357c86e46e806a
dir: /silk/silk_CNG.c/
/***********************************************************************
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BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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***********************************************************************/
#include "silk_main.h"
/* Generates excitation for CNG LPC synthesis */
SKP_INLINE void silk_CNG_exc(
SKP_int32 residual_Q10[], /* O CNG residual signal Q10 */
SKP_int32 exc_buf_Q10[], /* I Random samples buffer Q10 */
SKP_int32 Gain_Q16, /* I Gain to apply */
SKP_int length, /* I Length */
SKP_int32 *rand_seed /* I/O Seed to random index generator */
)
{
SKP_int32 seed;
SKP_int i, idx, exc_mask;
exc_mask = CNG_BUF_MASK_MAX;
while( exc_mask > length ) {
exc_mask = SKP_RSHIFT( exc_mask, 1 );
}
seed = *rand_seed;
for( i = 0; i < length; i++ ) {
seed = SKP_RAND( seed );
idx = ( SKP_int )( SKP_RSHIFT( seed, 24 ) & exc_mask );
SKP_assert( idx >= 0 );
SKP_assert( idx <= CNG_BUF_MASK_MAX );
residual_Q10[ i ] = ( SKP_int16 )SKP_SAT16( SKP_SMULWW( exc_buf_Q10[ idx ], Gain_Q16 ) );
}
*rand_seed = seed;
}
void silk_CNG_Reset(
silk_decoder_state *psDec /* I/O Decoder state */
)
{
SKP_int i, NLSF_step_Q15, NLSF_acc_Q15;
NLSF_step_Q15 = SKP_DIV32_16( SKP_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 */
SKP_int16 signal[], /* I/O Signal */
SKP_int length /* I Length of residual */
)
{
SKP_int i, j, subfr;
SKP_int32 sum_Q6, max_Gain_Q16;
SKP_int16 A_Q12[ MAX_LPC_ORDER ];
SKP_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 ] += SKP_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 */
SKP_memmove( &psCNG->CNG_exc_buf_Q10[ psDec->subfr_length ], psCNG->CNG_exc_buf_Q10, ( psDec->nb_subfr - 1 ) * psDec->subfr_length * sizeof( SKP_int32 ) );
SKP_memcpy( psCNG->CNG_exc_buf_Q10, &psDec->exc_Q10[ subfr * psDec->subfr_length ], psDec->subfr_length * sizeof( SKP_int32 ) );
/* Smooth gains */
for( i = 0; i < psDec->nb_subfr; i++ ) {
psCNG->CNG_smth_Gain_Q16 += SKP_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 */
SKP_memcpy( CNG_sig_Q10, psCNG->CNG_synth_state, MAX_LPC_ORDER * sizeof( SKP_int32 ) );
for( i = 0; i < length; i++ ) {
/* Partially unrolled */
sum_Q6 = SKP_SMULWB( CNG_sig_Q10[ MAX_LPC_ORDER + i - 1 ], A_Q12[ 0 ] );
sum_Q6 = SKP_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 2 ], A_Q12[ 1 ] );
sum_Q6 = SKP_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 3 ], A_Q12[ 2 ] );
sum_Q6 = SKP_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 4 ], A_Q12[ 3 ] );
sum_Q6 = SKP_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 5 ], A_Q12[ 4 ] );
sum_Q6 = SKP_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 6 ], A_Q12[ 5 ] );
sum_Q6 = SKP_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 7 ], A_Q12[ 6 ] );
sum_Q6 = SKP_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 8 ], A_Q12[ 7 ] );
sum_Q6 = SKP_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 9 ], A_Q12[ 8 ] );
sum_Q6 = SKP_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 10 ], A_Q12[ 9 ] );
for( j = 10; j < psDec->LPC_order; j++ ) {
sum_Q6 = SKP_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - j - 1 ], A_Q12[ j ] );
}
/* Update states */
CNG_sig_Q10[ MAX_LPC_ORDER + i ] = SKP_ADD_LSHIFT( CNG_sig_Q10[ MAX_LPC_ORDER + i ], sum_Q6, 4 );
signal[ i ] = SKP_ADD_SAT16( signal[ i ], SKP_RSHIFT_ROUND( sum_Q6, 6 ) );
}
SKP_memcpy( psCNG->CNG_synth_state, &CNG_sig_Q10[ length ], MAX_LPC_ORDER * sizeof( SKP_int32 ) );
} else {
SKP_memset( psCNG->CNG_synth_state, 0, psDec->LPC_order * sizeof( SKP_int32 ) );
}
}