/*********************************************************************** | |
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***********************************************************************/ | |
#include "SKP_Silk_main.h" | |
/* Generates excitation for CNG LPC synthesis */ | |
SKP_INLINE void SKP_Silk_CNG_exc( | |
SKP_int16 residual[], /* O CNG residual signal Q0 */ | |
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[ i ] = ( SKP_int16 )SKP_SAT16( SKP_RSHIFT_ROUND( SKP_SMULWW( exc_buf_Q10[ idx ], Gain_Q16 ), 10 ) ); | |
} | |
*rand_seed = seed; | |
} | |
void SKP_Silk_CNG_Reset( | |
SKP_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 SKP_Silk_CNG( | |
SKP_Silk_decoder_state *psDec, /* I/O Decoder state */ | |
SKP_Silk_decoder_control *psDecCtrl, /* I/O Decoder control */ | |
SKP_int16 signal[], /* I/O Signal */ | |
SKP_int length /* I Length of residual */ | |
) | |
{ | |
SKP_int i, subfr; | |
SKP_int32 tmp_32, Gain_Q26, max_Gain_Q16; | |
SKP_int16 LPC_buf[ MAX_LPC_ORDER ]; | |
SKP_int16 CNG_sig[ MAX_FRAME_LENGTH ]; | |
SKP_Silk_CNG_struct *psCNG; | |
psCNG = &psDec->sCNG; | |
if( psDec->fs_kHz != psCNG->fs_kHz ) { | |
/* Reset state */ | |
SKP_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 and / or when low speech activity */ | |
if( psDec->lossCnt ) { | |
/* Generate CNG excitation */ | |
SKP_Silk_CNG_exc( CNG_sig, psCNG->CNG_exc_buf_Q10, | |
psCNG->CNG_smth_Gain_Q16, length, &psCNG->rand_seed ); | |
/* Convert CNG NLSF to filter representation */ | |
SKP_Silk_NLSF2A_stable( LPC_buf, psCNG->CNG_smth_NLSF_Q15, psDec->LPC_order ); | |
Gain_Q26 = ( SKP_int32 )1 << 26; /* 1.0 */ | |
/* Generate CNG signal, by synthesis filtering */ | |
if( psDec->LPC_order == 16 ) { | |
SKP_Silk_LPC_synthesis_order16( CNG_sig, LPC_buf, | |
Gain_Q26, psCNG->CNG_synth_state, CNG_sig, length ); | |
} else { | |
SKP_Silk_LPC_synthesis_filter( CNG_sig, LPC_buf, | |
Gain_Q26, psCNG->CNG_synth_state, CNG_sig, length, psDec->LPC_order ); | |
} | |
/* Mix with signal */ | |
for( i = 0; i < length; i++ ) { | |
tmp_32 = signal[ i ] + CNG_sig[ i ]; | |
signal[ i ] = SKP_SAT16( tmp_32 ); | |
} | |
} else { | |
SKP_memset( psCNG->CNG_synth_state, 0, psDec->LPC_order * sizeof( SKP_int32 ) ); | |
} | |
} |