/* Find pitch lags */
void SKP_Silk_find_pitch_lags_FIX(
SKP_Silk_encoder_state_FIX *psEnc, /* I/O encoder state */
SKP_Silk_encoder_control_FIX *psEncCtrl, /* I/O encoder control */
SKP_int16 res[], /* O residual */
const SKP_int16 x[] /* I Speech signal */
)
{
SKP_Silk_predict_state_FIX *psPredSt = &psEnc->sPred;
SKP_int buf_len, i, scale;
SKP_int32 thrhld_Q15, res_nrg;
const SKP_int16 *x_buf, *x_buf_ptr;
SKP_int16 Wsig[ FIND_PITCH_LPC_WIN_MAX ], *Wsig_ptr;
SKP_int32 auto_corr[ MAX_FIND_PITCH_LPC_ORDER + 1 ];
SKP_int16 rc_Q15[ MAX_FIND_PITCH_LPC_ORDER ];
SKP_int32 A_Q24[ MAX_FIND_PITCH_LPC_ORDER ];
SKP_int32 FiltState[ MAX_FIND_PITCH_LPC_ORDER ];
SKP_int16 A_Q12[ MAX_FIND_PITCH_LPC_ORDER ];
/******************************************/
/* Setup buffer lengths etc based on Fs */
/******************************************/
buf_len = SKP_ADD_LSHIFT( psEnc->sCmn.la_pitch, psEnc->sCmn.frame_length, 1 );
/* Safty check */
SKP_assert( buf_len >= psPredSt->pitch_LPC_win_length );
x_buf = x - psEnc->sCmn.frame_length;
/*************************************/
/* Estimate LPC AR coefficients */
/*************************************/
/* Calculate windowed signal */
/* First LA_LTP samples */
x_buf_ptr = x_buf + buf_len - psPredSt->pitch_LPC_win_length;
Wsig_ptr = Wsig;
SKP_Silk_apply_sine_window_new( Wsig_ptr, x_buf_ptr, 1, psEnc->sCmn.la_pitch );
/* Middle un - windowed samples */
Wsig_ptr += psEnc->sCmn.la_pitch;
x_buf_ptr += psEnc->sCmn.la_pitch;
SKP_memcpy( Wsig_ptr, x_buf_ptr, ( psPredSt->pitch_LPC_win_length - SKP_LSHIFT( psEnc->sCmn.la_pitch, 1 ) ) * sizeof( SKP_int16 ) );
/* Last LA_LTP samples */
Wsig_ptr += psPredSt->pitch_LPC_win_length - SKP_LSHIFT( psEnc->sCmn.la_pitch, 1 );
x_buf_ptr += psPredSt->pitch_LPC_win_length - SKP_LSHIFT( psEnc->sCmn.la_pitch, 1 );
SKP_Silk_apply_sine_window_new( Wsig_ptr, x_buf_ptr, 2, psEnc->sCmn.la_pitch );
/* Calculate autocorrelation sequence */
SKP_Silk_autocorr( auto_corr, &scale, Wsig, psPredSt->pitch_LPC_win_length, psEnc->sCmn.pitchEstimationLPCOrder + 1 );
/* Add white noise, as fraction of energy */
auto_corr[ 0 ] = SKP_SMLAWB( auto_corr[ 0 ], auto_corr[ 0 ], SKP_FIX_CONST( FIND_PITCH_WHITE_NOISE_FRACTION, 16 ) );
/* Calculate the reflection coefficients using schur */
res_nrg = SKP_Silk_schur( rc_Q15, auto_corr, psEnc->sCmn.pitchEstimationLPCOrder );
/* Prediction gain */
psEncCtrl->predGain_Q16 = SKP_DIV32_varQ( auto_corr[ 0 ], SKP_max_int( res_nrg, 1 ), 16 );
/* Convert reflection coefficients to prediction coefficients */
SKP_Silk_k2a( A_Q24, rc_Q15, psEnc->sCmn.pitchEstimationLPCOrder );
/* Convert From 32 bit Q24 to 16 bit Q12 coefs */
for( i = 0; i < psEnc->sCmn.pitchEstimationLPCOrder; i++ ) {
A_Q12[ i ] = ( SKP_int16 )SKP_SAT16( SKP_RSHIFT( A_Q24[ i ], 12 ) );
}
/* Do BWE */
SKP_Silk_bwexpander( A_Q12, psEnc->sCmn.pitchEstimationLPCOrder, SKP_FIX_CONST( FIND_PITCH_BANDWITH_EXPANSION, 16 ) );
/*****************************************/
/* LPC analysis filtering */
/*****************************************/
SKP_memset( FiltState, 0, psEnc->sCmn.pitchEstimationLPCOrder * sizeof( SKP_int32 ) ); /* Not really necessary, but Valgrind will complain otherwise */
SKP_Silk_MA_Prediction( x_buf, A_Q12, FiltState, res, buf_len, psEnc->sCmn.pitchEstimationLPCOrder );
SKP_memset( res, 0, psEnc->sCmn.pitchEstimationLPCOrder * sizeof( SKP_int16 ) );
/* Threshold for pitch estimator */
thrhld_Q15 = SKP_FIX_CONST( 0.45, 15 );
thrhld_Q15 = SKP_SMLABB( thrhld_Q15, SKP_FIX_CONST( -0.004, 15 ), psEnc->sCmn.pitchEstimationLPCOrder );
thrhld_Q15 = SKP_SMLABB( thrhld_Q15, SKP_FIX_CONST( -0.1, 7 ), psEnc->speech_activity_Q8 );
thrhld_Q15 = SKP_SMLABB( thrhld_Q15, SKP_FIX_CONST( 0.15, 15 ), psEnc->sCmn.prev_sigtype );
thrhld_Q15 = SKP_SMLAWB( thrhld_Q15, SKP_FIX_CONST( -0.1, 16 ), psEncCtrl->input_tilt_Q15 );
thrhld_Q15 = SKP_SAT16( thrhld_Q15 );
/*****************************************/
/* Call pitch estimator */
/*****************************************/
psEncCtrl->sCmn.sigtype = SKP_Silk_pitch_analysis_core( res, psEncCtrl->sCmn.pitchL, &psEncCtrl->sCmn.lagIndex,
&psEncCtrl->sCmn.contourIndex, &psEnc->LTPCorr_Q15, psEnc->sCmn.prevLag, psEnc->sCmn.pitchEstimationThreshold_Q16,
( SKP_int16 )thrhld_Q15, psEnc->sCmn.fs_kHz, psEnc->sCmn.pitchEstimationComplexity, SKP_FALSE );
}
/* Find pitch lags */
void SKP_Silk_find_pitch_lags_FIX(
SKP_Silk_encoder_state_FIX *psEnc, /* I/O encoder state */
SKP_Silk_encoder_control_FIX *psEncCtrl, /* I/O encoder control */
SKP_int16 res[], /* O residual */
const SKP_int16 x[] /* I Speech signal */
)
{
SKP_Silk_predict_state_FIX *psPredSt = &psEnc->sPred;
SKP_int buf_len, i;
SKP_int32 scale;
SKP_int32 thrhld_Q15;
const SKP_int16 *x_buf, *x_buf_ptr;
SKP_int16 Wsig[ FIND_PITCH_LPC_WIN_MAX ], *Wsig_ptr;
SKP_int32 auto_corr[ FIND_PITCH_LPC_ORDER_MAX + 1 ];
SKP_int16 rc_Q15[ FIND_PITCH_LPC_ORDER_MAX ];
SKP_int32 A_Q24[ FIND_PITCH_LPC_ORDER_MAX ];
SKP_int32 FiltState[ FIND_PITCH_LPC_ORDER_MAX ];
SKP_int16 A_Q12[ FIND_PITCH_LPC_ORDER_MAX ];
/******************************************/
/* Setup buffer lengths etc based of Fs. */
/******************************************/
buf_len = SKP_ADD_LSHIFT( psEnc->sCmn.la_pitch, psEnc->sCmn.frame_length, 1 );
/* Safty check */
SKP_assert( buf_len >= psPredSt->pitch_LPC_win_length );
x_buf = x - psEnc->sCmn.frame_length;
/*************************************/
/* Estimate LPC AR coeficients */
/*************************************/
/* Calculate windowed signal */
/* First LA_LTP samples */
x_buf_ptr = x_buf + buf_len - psPredSt->pitch_LPC_win_length;
Wsig_ptr = Wsig;
SKP_Silk_apply_sine_window( Wsig_ptr, x_buf_ptr, 1, psEnc->sCmn.la_pitch );
/* Middle un - windowed samples */
Wsig_ptr += psEnc->sCmn.la_pitch;
x_buf_ptr += psEnc->sCmn.la_pitch;
SKP_memcpy( Wsig_ptr, x_buf_ptr, ( psPredSt->pitch_LPC_win_length - SKP_LSHIFT( psEnc->sCmn.la_pitch, 1 ) ) * sizeof( SKP_int16 ) );
/* Last LA_LTP samples */
Wsig_ptr += psPredSt->pitch_LPC_win_length - SKP_LSHIFT( psEnc->sCmn.la_pitch, 1 );
x_buf_ptr += psPredSt->pitch_LPC_win_length - SKP_LSHIFT( psEnc->sCmn.la_pitch, 1 );
SKP_Silk_apply_sine_window( Wsig_ptr, x_buf_ptr, 2, psEnc->sCmn.la_pitch );
/* Calculate autocorrelation sequence */
SKP_Silk_autocorr( auto_corr, &scale, Wsig, psPredSt->pitch_LPC_win_length, psEnc->sCmn.pitchEstimationLPCOrder + 1 );
/* add white noise, as fraction of energy */
auto_corr[ 0 ] = SKP_SMLAWB( auto_corr[ 0 ], auto_corr[ 0 ], FIND_PITCH_WHITE_NOISE_FRACTION_Q16 );
/* calculate the reflection coefficients using schur */
SKP_Silk_schur( rc_Q15, auto_corr, psEnc->sCmn.pitchEstimationLPCOrder );
/* convert reflection coefficients to prediction coefficients */
SKP_Silk_k2a( A_Q24, rc_Q15, psEnc->sCmn.pitchEstimationLPCOrder );
/* Convert From 32 bit Q24 to 16 bit Q12 coefs */
for( i = 0; i < psEnc->sCmn.pitchEstimationLPCOrder; i++ ) {
A_Q12[ i ] = ( SKP_int16 )SKP_SAT16( SKP_RSHIFT( A_Q24[ i ], 12 ) );
}
/* Do BWE */
SKP_Silk_bwexpander( A_Q12, psEnc->sCmn.pitchEstimationLPCOrder, FIND_PITCH_BANDWITH_EXPANSION_Q16 );
/*****************************************/
/* LPC analysis filtering */
/*****************************************/
SKP_memset( FiltState, 0, psEnc->sCmn.pitchEstimationLPCOrder * sizeof( SKP_int16 ) );
SKP_Silk_MA_Prediction( x_buf, A_Q12, FiltState, res, buf_len, psEnc->sCmn.pitchEstimationLPCOrder );
SKP_memset( res, 0, psEnc->sCmn.pitchEstimationLPCOrder * sizeof( SKP_int16 ) );
/* Threshold for pitch estimator */
thrhld_Q15 = ( 1 << 14 ); // 0.5f in Q15
thrhld_Q15 = SKP_SMLABB( thrhld_Q15, -131, psEnc->sCmn.pitchEstimationLPCOrder );
thrhld_Q15 = SKP_SMLABB( thrhld_Q15, -13, ( SKP_int16 )SKP_Silk_SQRT_APPROX( SKP_LSHIFT( ( SKP_int32 )psEnc->speech_activity_Q8, 8 ) ) );
thrhld_Q15 = SKP_SMLABB( thrhld_Q15, 4587, psEnc->sCmn.prev_sigtype );
thrhld_Q15 = SKP_MLA( thrhld_Q15, -31, SKP_RSHIFT( psEncCtrl->input_tilt_Q15, 8 ) );
thrhld_Q15 = SKP_SAT16( thrhld_Q15 );
/*****************************************/
/* Call Pitch estimator */
/*****************************************/
psEncCtrl->sCmn.sigtype = SKP_Silk_pitch_analysis_core( res, psEncCtrl->sCmn.pitchL, &psEncCtrl->sCmn.lagIndex,
&psEncCtrl->sCmn.contourIndex, &psEnc->LTPCorr_Q15, psEnc->sCmn.prevLag, psEnc->pitchEstimationThreshold_Q16,
( SKP_int16 )thrhld_Q15, psEnc->sCmn.fs_kHz, psEnc->sCmn.pitchEstimationComplexity );
}
