SKP_int SKP_Silk_VAD_Init( /* O Return value, 0 if success */
SKP_Silk_VAD_state *psSilk_VAD /* I/O Pointer to Silk VAD state */
)
{
SKP_int b, ret = 0;
/* reset state memory */
SKP_memset( psSilk_VAD, 0, sizeof( SKP_Silk_VAD_state ) );
/* init noise levels */
/* Initialize array with approx pink noise levels (psd proportional to inverse of frequency) */
for( b = 0; b < VAD_N_BANDS; b++ ) {
psSilk_VAD->NoiseLevelBias[ b ] = SKP_max_32( SKP_DIV32_16( VAD_NOISE_LEVELS_BIAS, b + 1 ), 1 );
}
/* Initialize state */
for( b = 0; b < VAD_N_BANDS; b++ ) {
psSilk_VAD->NL[ b ] = SKP_MUL( 100, psSilk_VAD->NoiseLevelBias[ b ] );
psSilk_VAD->inv_NL[ b ] = SKP_DIV32( SKP_int32_MAX, psSilk_VAD->NL[ b ] );
}
psSilk_VAD->counter = 15;
/* init smoothed energy-to-noise ratio*/
for( b = 0; b < VAD_N_BANDS; b++ ) {
psSilk_VAD->NrgRatioSmth_Q8[ b ] = 100 * 256; /* 100 * 256 --> 20 dB SNR */
}
return( ret );
}
/* Glues concealed frames with new good recieved frames */
void SKP_Silk_PLC_glue_frames(
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, energy_shift;
SKP_int32 energy;
SKP_Silk_PLC_struct *psPLC;
psPLC = &psDec->sPLC;
if( psDec->lossCnt ) {
/* Calculate energy in concealed residual */
SKP_Silk_sum_sqr_shift( &psPLC->conc_energy, &psPLC->conc_energy_shift, signal, length );
psPLC->last_frame_lost = 1;
} else {
if( psDec->sPLC.last_frame_lost ) {
/* Calculate residual in decoded signal if last frame was lost */
SKP_Silk_sum_sqr_shift( &energy, &energy_shift, signal, length );
/* Normalize energies */
if( energy_shift > psPLC->conc_energy_shift ) {
psPLC->conc_energy = SKP_RSHIFT( psPLC->conc_energy, energy_shift - psPLC->conc_energy_shift );
} else if( energy_shift < psPLC->conc_energy_shift ) {
energy = SKP_RSHIFT( energy, psPLC->conc_energy_shift - energy_shift );
}
/* Fade in the energy difference */
if( energy > psPLC->conc_energy ) {
SKP_int32 frac_Q24, LZ;
SKP_int32 gain_Q12, slope_Q12;
LZ = SKP_Silk_CLZ32( psPLC->conc_energy );
LZ = LZ - 1;
psPLC->conc_energy = SKP_LSHIFT( psPLC->conc_energy, LZ );
energy = SKP_RSHIFT( energy, SKP_max_32( 24 - LZ, 0 ) );
frac_Q24 = SKP_DIV32( psPLC->conc_energy, SKP_max( energy, 1 ) );
gain_Q12 = SKP_Silk_SQRT_APPROX( frac_Q24 );
slope_Q12 = SKP_DIV32_16( ( 1 << 12 ) - gain_Q12, length );
for( i = 0; i < length; i++ ) {
signal[ i ] = SKP_RSHIFT( SKP_MUL( gain_Q12, signal[ i ] ), 12 );
gain_Q12 += slope_Q12;
gain_Q12 = SKP_min( gain_Q12, ( 1 << 12 ) );
}
}
}
psPLC->last_frame_lost = 0;
}
}
/* uses SMLAWB(), requiring armv5E and higher. */
SKP_int32 SKP_Silk_schur( /* O: Returns residual energy */
SKP_int16 *rc_Q15, /* O: reflection coefficients [order] Q15 */
const SKP_int32 *c, /* I: correlations [order+1] */
const SKP_int32 order /* I: prediction order */
)
{
SKP_int k, n, lz;
SKP_int32 C[ SKP_Silk_MAX_ORDER_LPC + 1 ][ 2 ];
SKP_int32 Ctmp1, Ctmp2, rc_tmp_Q15;
/* Get number of leading zeros */
lz = SKP_Silk_CLZ32( c[ 0 ] );
/* Copy correlations and adjust level to Q30 */
if( lz < 2 ) {
/* lz must be 1, so shift one to the right */
for( k = 0; k < order + 1; k++ ) {
C[ k ][ 0 ] = C[ k ][ 1 ] = SKP_RSHIFT( c[ k ], 1 );
}
} else if( lz > 2 ) {
/* Shift to the left */
lz -= 2;
for( k = 0; k < order + 1; k++ ) {
C[ k ][ 0 ] = C[ k ][ 1 ] = SKP_LSHIFT( c[k], lz );
}
} else {
/* No need to shift */
for( k = 0; k < order + 1; k++ ) {
C[ k ][ 0 ] = C[ k ][ 1 ] = c[ k ];
}
}
for( k = 0; k < order; k++ ) {
/* Get reflection coefficient */
rc_tmp_Q15 = -SKP_DIV32_16( C[ k + 1 ][ 0 ], SKP_max_32( SKP_RSHIFT( C[ 0 ][ 1 ], 15 ), 1 ) );
/* Clip (shouldn't happen for properly conditioned inputs) */
rc_tmp_Q15 = SKP_SAT16( rc_tmp_Q15 );
/* Store */
rc_Q15[ k ] = (SKP_int16)rc_tmp_Q15;
/* Update correlations */
for( n = 0; n < order - k; n++ ) {
Ctmp1 = C[ n + k + 1 ][ 0 ];
Ctmp2 = C[ n ][ 1 ];
C[ n + k + 1 ][ 0 ] = SKP_SMLAWB( Ctmp1, SKP_LSHIFT( Ctmp2, 1 ), rc_tmp_Q15 );
C[ n ][ 1 ] = SKP_SMLAWB( Ctmp2, SKP_LSHIFT( Ctmp1, 1 ), rc_tmp_Q15 );
}
}
/* return residual energy */
return C[0][1];
}
SKP_INLINE void SKP_Silk_LDL_factorize_FIX(
SKP_int32 *A, /* I Pointer to Symetric Square Matrix */
SKP_int M, /* I Size of Matrix */
SKP_int32 *L_Q16, /* I/O Pointer to Square Upper triangular Matrix */
inv_D_t *inv_D /* I/O Pointer to vector holding inverted diagonal elements of D */
)
{
SKP_int i, j, k, status, loop_count;
const SKP_int32 *ptr1, *ptr2;
SKP_int32 diag_min_value, tmp_32, err;
SKP_int32 v_Q0[ MAX_MATRIX_SIZE ], D_Q0[ MAX_MATRIX_SIZE ];
SKP_int32 one_div_diag_Q36, one_div_diag_Q40, one_div_diag_Q48;
SKP_assert( M <= MAX_MATRIX_SIZE );
status = 1;
diag_min_value = SKP_max_32( SKP_SMMUL( SKP_ADD_SAT32( A[ 0 ], A[ SKP_SMULBB( M, M ) - 1 ] ), SKP_FIX_CONST( FIND_LTP_COND_FAC, 31 ) ), 1 << 9 );
for( loop_count = 0; loop_count < M && status == 1; loop_count++ ) {
status = 0;
for( j = 0; j < M; j++ ) {
ptr1 = matrix_adr( L_Q16, j, 0, M );
tmp_32 = 0;
for( i = 0; i < j; i++ ) {
v_Q0[ i ] = SKP_SMULWW( D_Q0[ i ], ptr1[ i ] ); /* Q0 */
tmp_32 = SKP_SMLAWW( tmp_32, v_Q0[ i ], ptr1[ i ] ); /* Q0 */
}
tmp_32 = SKP_SUB32( matrix_ptr( A, j, j, M ), tmp_32 );
if( tmp_32 < diag_min_value ) {
tmp_32 = SKP_SUB32( SKP_SMULBB( loop_count + 1, diag_min_value ), tmp_32 );
/* Matrix not positive semi-definite, or ill conditioned */
for( i = 0; i < M; i++ ) {
matrix_ptr( A, i, i, M ) = SKP_ADD32( matrix_ptr( A, i, i, M ), tmp_32 );
}
status = 1;
break;
}
D_Q0[ j ] = tmp_32; /* always < max(Correlation) */
/* two-step division */
one_div_diag_Q36 = SKP_INVERSE32_varQ( tmp_32, 36 ); /* Q36 */
one_div_diag_Q40 = SKP_LSHIFT( one_div_diag_Q36, 4 ); /* Q40 */
err = SKP_SUB32( 1 << 24, SKP_SMULWW( tmp_32, one_div_diag_Q40 ) ); /* Q24 */
one_div_diag_Q48 = SKP_SMULWW( err, one_div_diag_Q40 ); /* Q48 */
/* Save 1/Ds */
inv_D[ j ].Q36_part = one_div_diag_Q36;
inv_D[ j ].Q48_part = one_div_diag_Q48;
matrix_ptr( L_Q16, j, j, M ) = 65536; /* 1.0 in Q16 */
ptr1 = matrix_adr( A, j, 0, M );
ptr2 = matrix_adr( L_Q16, j + 1, 0, M );
for( i = j + 1; i < M; i++ ) {
tmp_32 = 0;
for( k = 0; k < j; k++ ) {
tmp_32 = SKP_SMLAWW( tmp_32, v_Q0[ k ], ptr2[ k ] ); /* Q0 */
}
tmp_32 = SKP_SUB32( ptr1[ i ], tmp_32 ); /* always < max(Correlation) */
/* tmp_32 / D_Q0[j] : Divide to Q16 */
matrix_ptr( L_Q16, i, j, M ) = SKP_ADD32( SKP_SMMUL( tmp_32, one_div_diag_Q48 ),
SKP_RSHIFT( SKP_SMULWW( tmp_32, one_div_diag_Q36 ), 4 ) );
/* go to next column */
ptr2 += M;
}
}
}
SKP_assert( status == 0 );
}
void SKP_Silk_PLC_conceal(
SKP_Silk_decoder_state *psDec, /* I/O Decoder state */
SKP_Silk_decoder_control *psDecCtrl, /* I/O Decoder control */
SKP_int16 signal[], /* O concealed signal */
SKP_int length /* I length of residual */
)
{
SKP_int i, j, k;
SKP_int16 *B_Q14, exc_buf[ MAX_FRAME_LENGTH ], *exc_buf_ptr;
SKP_int16 rand_scale_Q14, A_Q12_tmp[ MAX_LPC_ORDER ];
SKP_int32 rand_seed, harm_Gain_Q15, rand_Gain_Q15;
SKP_int lag, idx, shift1, shift2;
SKP_int32 energy1, energy2, *rand_ptr, *pred_lag_ptr, Atmp;
SKP_int32 sig_Q10[ MAX_FRAME_LENGTH ], *sig_Q10_ptr, LPC_exc_Q10, LPC_pred_Q10, LTP_pred_Q14;
SKP_Silk_PLC_struct *psPLC;
psPLC = &psDec->sPLC;
/* Update LTP buffer */
SKP_memcpy( psDec->sLTP_Q16, &psDec->sLTP_Q16[ psDec->frame_length ], psDec->frame_length * sizeof( SKP_int32 ) );
/* LPC concealment. Apply BWE to previous LPC */
SKP_Silk_bwexpander( psPLC->prevLPC_Q12, psDec->LPC_order, BWE_COEF_Q16 );
/* Find random noise component */
/* Scale previous excitation signal */
exc_buf_ptr = exc_buf;
for( k = ( NB_SUBFR >> 1 ); k < NB_SUBFR; k++ ) {
for( i = 0; i < psDec->subfr_length; i++ ) {
exc_buf_ptr[ i ] = ( SKP_int16 )SKP_RSHIFT(
SKP_SMULWW( psDec->exc_Q10[ i + k * psDec->subfr_length ], psPLC->prevGain_Q16[ k ] ), 10 );
}
exc_buf_ptr += psDec->subfr_length;
}
/* Find the subframe with lowest energy of the last two and use that as random noise generator */
SKP_Silk_sum_sqr_shift( &energy1, &shift1, exc_buf, psDec->subfr_length );
SKP_Silk_sum_sqr_shift( &energy2, &shift2, &exc_buf[ psDec->subfr_length ], psDec->subfr_length );
if( SKP_RSHIFT( energy1, shift2 ) < SKP_RSHIFT( energy1, shift2 ) ) {
/* First sub-frame has lowest energy */
rand_ptr = &psDec->exc_Q10[ SKP_max_int( 0, 3 * psDec->subfr_length - RAND_BUF_SIZE ) ];
} else {
/* Second sub-frame has lowest energy */
rand_ptr = &psDec->exc_Q10[ SKP_max_int( 0, psDec->frame_length - RAND_BUF_SIZE ) ];
}
/* Setup Gain to random noise component */
B_Q14 = psPLC->LTPCoef_Q14;
rand_scale_Q14 = psPLC->randScale_Q14;
/* Setup attenuation gains */
harm_Gain_Q15 = HARM_ATT_Q15[ SKP_min_int( NB_ATT - 1, psDec->lossCnt ) ];
if( psDec->prev_sigtype == SIG_TYPE_VOICED ) {
rand_Gain_Q15 = PLC_RAND_ATTENUATE_V_Q15[ SKP_min_int( NB_ATT - 1, psDec->lossCnt ) ];
} else {
rand_Gain_Q15 = PLC_RAND_ATTENUATE_UV_Q15[ SKP_min_int( NB_ATT - 1, psDec->lossCnt ) ];
}
/* First Lost frame */
if( psDec->lossCnt == 0 ) {
rand_scale_Q14 = (1 << 14 );
/* Reduce random noise Gain for voiced frames */
if( psDec->prev_sigtype == SIG_TYPE_VOICED ) {
for( i = 0; i < LTP_ORDER; i++ ) {
rand_scale_Q14 -= B_Q14[ i ];
}
rand_scale_Q14 = SKP_max_16( 3277, rand_scale_Q14 ); /* 0.2 */
rand_scale_Q14 = ( SKP_int16 )SKP_RSHIFT( SKP_SMULBB( rand_scale_Q14, psPLC->prevLTP_scale_Q14 ), 14 );
}
/* Reduce random noise for unvoiced frames with high LPC gain */
if( psDec->prev_sigtype == SIG_TYPE_UNVOICED ) {
SKP_int32 invGain_Q30, down_scale_Q30;
SKP_Silk_LPC_inverse_pred_gain( &invGain_Q30, psPLC->prevLPC_Q12, psDec->LPC_order );
down_scale_Q30 = SKP_min_32( SKP_RSHIFT( ( 1 << 30 ), LOG2_INV_LPC_GAIN_HIGH_THRES ), invGain_Q30 );
down_scale_Q30 = SKP_max_32( SKP_RSHIFT( ( 1 << 30 ), LOG2_INV_LPC_GAIN_LOW_THRES ), down_scale_Q30 );
down_scale_Q30 = SKP_LSHIFT( down_scale_Q30, LOG2_INV_LPC_GAIN_HIGH_THRES );
rand_Gain_Q15 = SKP_RSHIFT( SKP_SMULWB( down_scale_Q30, rand_Gain_Q15 ), 14 );
}
}
rand_seed = psPLC->rand_seed;
lag = SKP_RSHIFT_ROUND( psPLC->pitchL_Q8, 8 );
psDec->sLTP_buf_idx = psDec->frame_length;
/***************************/
/* LTP synthesis filtering */
/***************************/
sig_Q10_ptr = sig_Q10;
for( k = 0; k < NB_SUBFR; k++ ) {
/* Setup pointer */
pred_lag_ptr = &psDec->sLTP_Q16[ psDec->sLTP_buf_idx - lag + LTP_ORDER / 2 ];
for( i = 0; i < psDec->subfr_length; i++ ) {
rand_seed = SKP_RAND( rand_seed );
idx = SKP_RSHIFT( rand_seed, 25 ) & RAND_BUF_MASK;
/* 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++;
/* Generate LPC residual */
LPC_exc_Q10 = SKP_LSHIFT( SKP_SMULWB( rand_ptr[ idx ], rand_scale_Q14 ), 2 ); /* Random noise part */
LPC_exc_Q10 = SKP_ADD32( LPC_exc_Q10, SKP_RSHIFT_ROUND( LTP_pred_Q14, 4 ) ); /* Harmonic part */
/* Update states */
psDec->sLTP_Q16[ psDec->sLTP_buf_idx ] = SKP_LSHIFT( LPC_exc_Q10, 6 );
psDec->sLTP_buf_idx++;
/* Save LPC residual */
sig_Q10_ptr[ i ] = LPC_exc_Q10;
}
sig_Q10_ptr += psDec->subfr_length;
/* Gradually reduce LTP gain */
for( j = 0; j < LTP_ORDER; j++ ) {
B_Q14[ j ] = SKP_RSHIFT( SKP_SMULBB( harm_Gain_Q15, B_Q14[ j ] ), 15 );
}
/* Gradually reduce excitation gain */
rand_scale_Q14 = SKP_RSHIFT( SKP_SMULBB( rand_scale_Q14, rand_Gain_Q15 ), 15 );
/* Slowly increase pitch lag */
psPLC->pitchL_Q8 += SKP_SMULWB( psPLC->pitchL_Q8, PITCH_DRIFT_FAC_Q16 );
psPLC->pitchL_Q8 = SKP_min_32( psPLC->pitchL_Q8, SKP_LSHIFT( SKP_SMULBB( MAX_PITCH_LAG_MS, psDec->fs_kHz ), 8 ) );
lag = SKP_RSHIFT_ROUND( psPLC->pitchL_Q8, 8 );
}
/***************************/
/* LPC synthesis filtering */
/***************************/
sig_Q10_ptr = sig_Q10;
/* Preload LPC coeficients to array on stack. Gives small performance gain */
SKP_memcpy( A_Q12_tmp, psPLC->prevLPC_Q12, psDec->LPC_order * sizeof( SKP_int16 ) );
SKP_assert( psDec->LPC_order >= 10 ); /* check that unrolling works */
for( k = 0; k < NB_SUBFR; k++ ) {
for( i = 0; i < psDec->subfr_length; i++ ){
/* unrolled */
Atmp = *( ( SKP_int32* )&A_Q12_tmp[ 0 ] ); /* read two coefficients at once */
LPC_pred_Q10 = SKP_SMULWB( psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 1 ], Atmp );
LPC_pred_Q10 = SKP_SMLAWT( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 2 ], Atmp );
Atmp = *( ( SKP_int32* )&A_Q12_tmp[ 2 ] );
LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 3 ], Atmp );
LPC_pred_Q10 = SKP_SMLAWT( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 4 ], Atmp );
Atmp = *( ( SKP_int32* )&A_Q12_tmp[ 4 ] );
LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 5 ], Atmp );
LPC_pred_Q10 = SKP_SMLAWT( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 6 ], Atmp );
Atmp = *( ( SKP_int32* )&A_Q12_tmp[ 6 ] );
LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 7 ], Atmp );
LPC_pred_Q10 = SKP_SMLAWT( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 8 ], Atmp );
Atmp = *( ( SKP_int32* )&A_Q12_tmp[ 8 ] );
LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 9 ], Atmp );
LPC_pred_Q10 = SKP_SMLAWT( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 10 ], Atmp );
for( j = 10 ; j < psDec->LPC_order ; j+=2 ) {
Atmp = *( ( SKP_int32* )&A_Q12_tmp[ j ] );
LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 1 - j ], Atmp );
LPC_pred_Q10 = SKP_SMLAWT( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 2 - j ], Atmp );
}
/* Add prediction to LPC residual */
sig_Q10_ptr[ i ] = SKP_ADD32( sig_Q10_ptr[ i ], LPC_pred_Q10 );
/* Update states */
psDec->sLPC_Q14[ MAX_LPC_ORDER + i ] = SKP_LSHIFT( sig_Q10_ptr[ i ], 4 );
}
sig_Q10_ptr += psDec->subfr_length;
/* Update LPC filter state */
SKP_memcpy( psDec->sLPC_Q14, &psDec->sLPC_Q14[ psDec->subfr_length ], MAX_LPC_ORDER * sizeof( SKP_int32 ) );
}
/* Scale with Gain */
for( i = 0; i < psDec->frame_length; i++ ) {
signal[ i ] = ( SKP_int16 )SKP_SAT16( SKP_RSHIFT_ROUND( SKP_SMULWW( sig_Q10[ i ], psPLC->prevGain_Q16[ NB_SUBFR - 1 ] ), 10 ) );
}
/**************************************/
/* Update states */
/**************************************/
psPLC->rand_seed = rand_seed;
psPLC->randScale_Q14 = rand_scale_Q14;
for( i = 0; i < NB_SUBFR; i++ ) {
psDecCtrl->pitchL[ i ] = lag;
}
}
void SKP_Silk_noise_shape_analysis_FIX(
SKP_Silk_encoder_state_FIX *psEnc, /* I/O Encoder state FIX */
SKP_Silk_encoder_control_FIX *psEncCtrl, /* I/O Encoder control FIX */
const SKP_int16 *pitch_res, /* I LPC residual from pitch analysis */
const SKP_int16 *x /* I Input signal [ frame_length + la_shape ] */
)
{
SKP_Silk_shape_state_FIX *psShapeSt = &psEnc->sShape;
SKP_int k, i, nSamples, Qnrg, b_Q14, warping_Q16, scale = 0;
SKP_int32 SNR_adj_dB_Q7, HarmBoost_Q16, HarmShapeGain_Q16, Tilt_Q16, tmp32;
SKP_int32 nrg, pre_nrg_Q30, log_energy_Q7, log_energy_prev_Q7, energy_variation_Q7;
SKP_int32 delta_Q16, BWExp1_Q16, BWExp2_Q16, gain_mult_Q16, gain_add_Q16, strength_Q16, b_Q8;
SKP_int32 auto_corr[ MAX_SHAPE_LPC_ORDER + 1 ];
SKP_int32 refl_coef_Q16[ MAX_SHAPE_LPC_ORDER ];
SKP_int32 AR1_Q24[ MAX_SHAPE_LPC_ORDER ];
SKP_int32 AR2_Q24[ MAX_SHAPE_LPC_ORDER ];
SKP_int16 x_windowed[ SHAPE_LPC_WIN_MAX ];
const SKP_int16 *x_ptr, *pitch_res_ptr;
SKP_int32 sqrt_nrg[ NB_SUBFR ], Qnrg_vec[ NB_SUBFR ];
/* Point to start of first LPC analysis block */
x_ptr = x - psEnc->sCmn.la_shape;
/****************/
/* CONTROL SNR */
/****************/
/* Reduce SNR_dB values if recent bitstream has exceeded TargetRate */
psEncCtrl->current_SNR_dB_Q7 = psEnc->SNR_dB_Q7 - SKP_SMULWB( SKP_LSHIFT( ( SKP_int32 )psEnc->BufferedInChannel_ms, 7 ),
SKP_FIX_CONST( 0.05, 16 ) );
/* Reduce SNR_dB if inband FEC used */
if( psEnc->speech_activity_Q8 > SKP_FIX_CONST( LBRR_SPEECH_ACTIVITY_THRES, 8 ) ) {
psEncCtrl->current_SNR_dB_Q7 -= SKP_RSHIFT( psEnc->inBandFEC_SNR_comp_Q8, 1 );
}
/****************/
/* GAIN CONTROL */
/****************/
/* Input quality is the average of the quality in the lowest two VAD bands */
psEncCtrl->input_quality_Q14 = ( SKP_int )SKP_RSHIFT( ( SKP_int32 )psEncCtrl->input_quality_bands_Q15[ 0 ]
+ psEncCtrl->input_quality_bands_Q15[ 1 ], 2 );
/* Coding quality level, between 0.0_Q0 and 1.0_Q0, but in Q14 */
psEncCtrl->coding_quality_Q14 = SKP_RSHIFT( SKP_Silk_sigm_Q15( SKP_RSHIFT_ROUND( psEncCtrl->current_SNR_dB_Q7 -
SKP_FIX_CONST( 18.0, 7 ), 4 ) ), 1 );
/* Reduce coding SNR during low speech activity */
b_Q8 = SKP_FIX_CONST( 1.0, 8 ) - psEnc->speech_activity_Q8;
b_Q8 = SKP_SMULWB( SKP_LSHIFT( b_Q8, 8 ), b_Q8 );
SNR_adj_dB_Q7 = SKP_SMLAWB( psEncCtrl->current_SNR_dB_Q7,
SKP_SMULBB( SKP_FIX_CONST( -BG_SNR_DECR_dB, 7 ) >> ( 4 + 1 ), b_Q8 ), // Q11
SKP_SMULWB( SKP_FIX_CONST( 1.0, 14 ) + psEncCtrl->input_quality_Q14, psEncCtrl->coding_quality_Q14 ) ); // Q12
if( psEncCtrl->sCmn.sigtype == SIG_TYPE_VOICED ) {
/* Reduce gains for periodic signals */
SNR_adj_dB_Q7 = SKP_SMLAWB( SNR_adj_dB_Q7, SKP_FIX_CONST( HARM_SNR_INCR_dB, 8 ), psEnc->LTPCorr_Q15 );
} else {
/* For unvoiced signals and low-quality input, adjust the quality slower than SNR_dB setting */
SNR_adj_dB_Q7 = SKP_SMLAWB( SNR_adj_dB_Q7,
SKP_SMLAWB( SKP_FIX_CONST( 6.0, 9 ), -SKP_FIX_CONST( 0.4, 18 ), psEncCtrl->current_SNR_dB_Q7 ),
SKP_FIX_CONST( 1.0, 14 ) - psEncCtrl->input_quality_Q14 );
}
/*************************/
/* SPARSENESS PROCESSING */
/*************************/
/* Set quantizer offset */
if( psEncCtrl->sCmn.sigtype == SIG_TYPE_VOICED ) {
/* Initally set to 0; may be overruled in process_gains(..) */
psEncCtrl->sCmn.QuantOffsetType = 0;
psEncCtrl->sparseness_Q8 = 0;
} else {
/* Sparseness measure, based on relative fluctuations of energy per 2 milliseconds */
nSamples = SKP_LSHIFT( psEnc->sCmn.fs_kHz, 1 );
energy_variation_Q7 = 0;
log_energy_prev_Q7 = 0;
pitch_res_ptr = pitch_res;
for( k = 0; k < FRAME_LENGTH_MS / 2; k++ ) {
SKP_Silk_sum_sqr_shift( &nrg, &scale, pitch_res_ptr, nSamples );
nrg += SKP_RSHIFT( nSamples, scale ); // Q(-scale)
log_energy_Q7 = SKP_Silk_lin2log( nrg );
if( k > 0 ) {
energy_variation_Q7 += SKP_abs( log_energy_Q7 - log_energy_prev_Q7 );
}
log_energy_prev_Q7 = log_energy_Q7;
pitch_res_ptr += nSamples;
}
psEncCtrl->sparseness_Q8 = SKP_RSHIFT( SKP_Silk_sigm_Q15( SKP_SMULWB( energy_variation_Q7 -
SKP_FIX_CONST( 5.0, 7 ), SKP_FIX_CONST( 0.1, 16 ) ) ), 7 );
/* Set quantization offset depending on sparseness measure */
if( psEncCtrl->sparseness_Q8 > SKP_FIX_CONST( SPARSENESS_THRESHOLD_QNT_OFFSET, 8 ) ) {
psEncCtrl->sCmn.QuantOffsetType = 0;
} else {
psEncCtrl->sCmn.QuantOffsetType = 1;
}
/* Increase coding SNR for sparse signals */
SNR_adj_dB_Q7 = SKP_SMLAWB( SNR_adj_dB_Q7, SKP_FIX_CONST( SPARSE_SNR_INCR_dB, 15 ), psEncCtrl->sparseness_Q8 - SKP_FIX_CONST( 0.5, 8 ) );
}
/*******************************/
/* Control bandwidth expansion */
/*******************************/
/* More BWE for signals with high prediction gain */
strength_Q16 = SKP_SMULWB( psEncCtrl->predGain_Q16, SKP_FIX_CONST( FIND_PITCH_WHITE_NOISE_FRACTION, 16 ) );
BWExp1_Q16 = BWExp2_Q16 = SKP_DIV32_varQ( SKP_FIX_CONST( BANDWIDTH_EXPANSION, 16 ),
SKP_SMLAWW( SKP_FIX_CONST( 1.0, 16 ), strength_Q16, strength_Q16 ), 16 );
delta_Q16 = SKP_SMULWB( SKP_FIX_CONST( 1.0, 16 ) - SKP_SMULBB( 3, psEncCtrl->coding_quality_Q14 ),
SKP_FIX_CONST( LOW_RATE_BANDWIDTH_EXPANSION_DELTA, 16 ) );
BWExp1_Q16 = SKP_SUB32( BWExp1_Q16, delta_Q16 );
BWExp2_Q16 = SKP_ADD32( BWExp2_Q16, delta_Q16 );
/* BWExp1 will be applied after BWExp2, so make it relative */
BWExp1_Q16 = SKP_DIV32_16( SKP_LSHIFT( BWExp1_Q16, 14 ), SKP_RSHIFT( BWExp2_Q16, 2 ) );
if( psEnc->sCmn.warping_Q16 > 0 ) {
/* Slightly more warping in analysis will move quantization noise up in frequency, where it's better masked */
warping_Q16 = SKP_SMLAWB( psEnc->sCmn.warping_Q16, psEncCtrl->coding_quality_Q14, SKP_FIX_CONST( 0.01, 18 ) );
} else {
warping_Q16 = 0;
}
/********************************************/
/* Compute noise shaping AR coefs and gains */
/********************************************/
for( k = 0; k < NB_SUBFR; k++ ) {
/* Apply window: sine slope followed by flat part followed by cosine slope */
SKP_int shift, slope_part, flat_part;
flat_part = psEnc->sCmn.fs_kHz * 5;
slope_part = SKP_RSHIFT( psEnc->sCmn.shapeWinLength - flat_part, 1 );
SKP_Silk_apply_sine_window_new( x_windowed, x_ptr, 1, slope_part );
shift = slope_part;
SKP_memcpy( x_windowed + shift, x_ptr + shift, flat_part * sizeof(SKP_int16) );
shift += flat_part;
SKP_Silk_apply_sine_window_new( x_windowed + shift, x_ptr + shift, 2, slope_part );
/* Update pointer: next LPC analysis block */
x_ptr += psEnc->sCmn.subfr_length;
if( psEnc->sCmn.warping_Q16 > 0 ) {
/* Calculate warped auto correlation */
SKP_Silk_warped_autocorrelation_FIX( auto_corr, &scale, x_windowed, warping_Q16, psEnc->sCmn.shapeWinLength, psEnc->sCmn.shapingLPCOrder );
} else {
/* Calculate regular auto correlation */
SKP_Silk_autocorr( auto_corr, &scale, x_windowed, psEnc->sCmn.shapeWinLength, psEnc->sCmn.shapingLPCOrder + 1 );
}
/* Add white noise, as a fraction of energy */
auto_corr[0] = SKP_ADD32( auto_corr[0], SKP_max_32( SKP_SMULWB( SKP_RSHIFT( auto_corr[ 0 ], 4 ),
SKP_FIX_CONST( SHAPE_WHITE_NOISE_FRACTION, 20 ) ), 1 ) );
/* Calculate the reflection coefficients using schur */
nrg = SKP_Silk_schur64( refl_coef_Q16, auto_corr, psEnc->sCmn.shapingLPCOrder );
SKP_assert( nrg >= 0 );
/* Convert reflection coefficients to prediction coefficients */
SKP_Silk_k2a_Q16( AR2_Q24, refl_coef_Q16, psEnc->sCmn.shapingLPCOrder );
Qnrg = -scale; // range: -12...30
SKP_assert( Qnrg >= -12 );
SKP_assert( Qnrg <= 30 );
/* Make sure that Qnrg is an even number */
if( Qnrg & 1 ) {
Qnrg -= 1;
nrg >>= 1;
}
tmp32 = SKP_Silk_SQRT_APPROX( nrg );
Qnrg >>= 1; // range: -6...15
sqrt_nrg[ k ] = tmp32;
Qnrg_vec[ k ] = Qnrg;
psEncCtrl->Gains_Q16[ k ] = SKP_LSHIFT_SAT32( tmp32, 16 - Qnrg );
if( psEnc->sCmn.warping_Q16 > 0 ) {
/* Adjust gain for warping */
gain_mult_Q16 = warped_gain( AR2_Q24, warping_Q16, psEnc->sCmn.shapingLPCOrder );
SKP_assert( psEncCtrl->Gains_Q16[ k ] >= 0 );
psEncCtrl->Gains_Q16[ k ] = SKP_SMULWW( psEncCtrl->Gains_Q16[ k ], gain_mult_Q16 );
if( psEncCtrl->Gains_Q16[ k ] < 0 ) {
psEncCtrl->Gains_Q16[ k ] = SKP_int32_MAX;
}
}
/* Bandwidth expansion for synthesis filter shaping */
SKP_Silk_bwexpander_32( AR2_Q24, psEnc->sCmn.shapingLPCOrder, BWExp2_Q16 );
/* Compute noise shaping filter coefficients */
SKP_memcpy( AR1_Q24, AR2_Q24, psEnc->sCmn.shapingLPCOrder * sizeof( SKP_int32 ) );
/* Bandwidth expansion for analysis filter shaping */
SKP_assert( BWExp1_Q16 <= SKP_FIX_CONST( 1.0, 16 ) );
SKP_Silk_bwexpander_32( AR1_Q24, psEnc->sCmn.shapingLPCOrder, BWExp1_Q16 );
/* Ratio of prediction gains, in energy domain */
SKP_Silk_LPC_inverse_pred_gain_Q24( &pre_nrg_Q30, AR2_Q24, psEnc->sCmn.shapingLPCOrder );
SKP_Silk_LPC_inverse_pred_gain_Q24( &nrg, AR1_Q24, psEnc->sCmn.shapingLPCOrder );
//psEncCtrl->GainsPre[ k ] = 1.0f - 0.7f * ( 1.0f - pre_nrg / nrg ) = 0.3f + 0.7f * pre_nrg / nrg;
pre_nrg_Q30 = SKP_LSHIFT32( SKP_SMULWB( pre_nrg_Q30, SKP_FIX_CONST( 0.7, 15 ) ), 1 );
psEncCtrl->GainsPre_Q14[ k ] = ( SKP_int ) SKP_FIX_CONST( 0.3, 14 ) + SKP_DIV32_varQ( pre_nrg_Q30, nrg, 14 );
/* Convert to monic warped prediction coefficients and limit absolute values */
limit_warped_coefs( AR2_Q24, AR1_Q24, warping_Q16, SKP_FIX_CONST( 3.999, 24 ), psEnc->sCmn.shapingLPCOrder );
/* Convert from Q24 to Q13 and store in int16 */
for( i = 0; i < psEnc->sCmn.shapingLPCOrder; i++ ) {
psEncCtrl->AR1_Q13[ k * MAX_SHAPE_LPC_ORDER + i ] = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( AR1_Q24[ i ], 11 ) );
psEncCtrl->AR2_Q13[ k * MAX_SHAPE_LPC_ORDER + i ] = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( AR2_Q24[ i ], 11 ) );
}
}
void SKP_Silk_noise_shape_analysis_FIX(
SKP_Silk_encoder_state_FIX *psEnc, /* I/O Encoder state FIX */
SKP_Silk_encoder_control_FIX *psEncCtrl, /* I/O Encoder control FIX */
const SKP_int16 *pitch_res, /* I LPC residual from pitch analysis */
const SKP_int16 *x /* I Input signal [ 2 * frame_length + la_shape ]*/
)
{
SKP_Silk_shape_state_FIX *psShapeSt = &psEnc->sShape;
SKP_int k, nSamples, lz, Qnrg, b_Q14, scale = 0, sz;
SKP_int32 SNR_adj_dB_Q7, HarmBoost_Q16, HarmShapeGain_Q16, Tilt_Q16, tmp32;
SKP_int32 nrg, pre_nrg_Q30, log_energy_Q7, log_energy_prev_Q7, energy_variation_Q7;
SKP_int32 delta_Q16, BWExp1_Q16, BWExp2_Q16, gain_mult_Q16, gain_add_Q16, strength_Q16, b_Q8;
SKP_int32 auto_corr[ SHAPE_LPC_ORDER_MAX + 1 ];
SKP_int32 refl_coef_Q16[ SHAPE_LPC_ORDER_MAX ];
SKP_int32 AR_Q24[ SHAPE_LPC_ORDER_MAX ];
SKP_int16 x_windowed[ SHAPE_LPC_WIN_MAX ];
const SKP_int16 *x_ptr, *pitch_res_ptr;
SKP_int32 sqrt_nrg[ NB_SUBFR ], Qnrg_vec[ NB_SUBFR ];
/* Point to start of first LPC analysis block */
x_ptr = x + psEnc->sCmn.la_shape - SKP_SMULBB( SHAPE_LPC_WIN_MS, psEnc->sCmn.fs_kHz ) + psEnc->sCmn.frame_length / NB_SUBFR;
/****************/
/* CONTROL SNR */
/****************/
/* Reduce SNR_dB values if recent bitstream has exceeded TargetRate */
psEncCtrl->current_SNR_dB_Q7 = psEnc->SNR_dB_Q7 - SKP_SMULWB( SKP_LSHIFT( ( SKP_int32 )psEnc->BufferedInChannel_ms, 7 ), 3277 );
/* Reduce SNR_dB if inband FEC used */
if( psEnc->speech_activity_Q8 > LBRR_SPEECH_ACTIVITY_THRES_Q8 ) {
psEncCtrl->current_SNR_dB_Q7 -= SKP_RSHIFT( psEnc->inBandFEC_SNR_comp_Q8, 1 );
}
/****************/
/* GAIN CONTROL */
/****************/
/* Input quality is the average of the quality in the lowest two VAD bands */
psEncCtrl->input_quality_Q14 = ( SKP_int )SKP_RSHIFT( ( SKP_int32 )psEncCtrl->input_quality_bands_Q15[ 0 ]
+ psEncCtrl->input_quality_bands_Q15[ 1 ], 2 );
/* Coding quality level, between 0.0_Q0 and 1.0_Q0, but in Q14 */
psEncCtrl->coding_quality_Q14 = SKP_RSHIFT( SKP_Silk_sigm_Q15( SKP_RSHIFT_ROUND( psEncCtrl->current_SNR_dB_Q7 - ( 18 << 7 ), 4 ) ), 1 );
/* Reduce coding SNR during low speech activity */
b_Q8 = ( 1 << 8 ) - psEnc->speech_activity_Q8;
b_Q8 = SKP_SMULWB( SKP_LSHIFT( b_Q8, 8 ), b_Q8 );
SNR_adj_dB_Q7 = SKP_SMLAWB( psEncCtrl->current_SNR_dB_Q7,
SKP_SMULBB( -BG_SNR_DECR_dB_Q7 >> ( 4 + 1 ), b_Q8 ), // Q11
SKP_SMULWB( ( 1 << 14 ) + psEncCtrl->input_quality_Q14, psEncCtrl->coding_quality_Q14 ) ); // Q12
if( psEncCtrl->sCmn.sigtype == SIG_TYPE_VOICED ) {
/* Reduce gains for periodic signals */
SNR_adj_dB_Q7 = SKP_SMLAWB( SNR_adj_dB_Q7, HARM_SNR_INCR_dB_Q7 << 1, psEnc->LTPCorr_Q15 );
} else {
/* For unvoiced signals and low-quality input, adjust the quality slower than SNR_dB setting */
SNR_adj_dB_Q7 = SKP_SMLAWB( SNR_adj_dB_Q7,
SKP_SMLAWB( 6 << ( 7 + 2 ), -104856, psEncCtrl->current_SNR_dB_Q7 ), //-104856_Q18 = -0.4_Q0, Q9
( 1 << 14 ) - psEncCtrl->input_quality_Q14 ); // Q14
}
/*************************/
/* SPARSENESS PROCESSING */
/*************************/
/* Set quantizer offset */
if( psEncCtrl->sCmn.sigtype == SIG_TYPE_VOICED ) {
/* Initally set to 0; may be overruled in process_gains(..) */
psEncCtrl->sCmn.QuantOffsetType = 0;
psEncCtrl->sparseness_Q8 = 0;
} else {
/* Sparseness measure, based on relative fluctuations of energy per 2 milliseconds */
nSamples = SKP_LSHIFT( psEnc->sCmn.fs_kHz, 1 );
energy_variation_Q7 = 0;
log_energy_prev_Q7 = 0;
pitch_res_ptr = pitch_res;
for( k = 0; k < FRAME_LENGTH_MS / 2; k++ ) {
SKP_Silk_sum_sqr_shift( &nrg, &scale, pitch_res_ptr, nSamples );
nrg += SKP_RSHIFT( nSamples, scale ); // Q(-scale)
log_energy_Q7 = SKP_Silk_lin2log( nrg );
if( k > 0 ) {
energy_variation_Q7 += SKP_abs( log_energy_Q7 - log_energy_prev_Q7 );
}
log_energy_prev_Q7 = log_energy_Q7;
pitch_res_ptr += nSamples;
}
psEncCtrl->sparseness_Q8 = SKP_RSHIFT( SKP_Silk_sigm_Q15( SKP_SMULWB( energy_variation_Q7 - ( 5 << 7 ), 6554 ) ), 7 ); // 6554_Q16 = 0.1_Q0
/* Set quantization offset depending on sparseness measure */
if( psEncCtrl->sparseness_Q8 > SPARSENESS_THRESHOLD_QNT_OFFSET_Q8 ) {
psEncCtrl->sCmn.QuantOffsetType = 0;
} else {
psEncCtrl->sCmn.QuantOffsetType = 1;
}
/* Increase coding SNR for sparse signals */
SNR_adj_dB_Q7 = SKP_SMLAWB( SNR_adj_dB_Q7, SPARSE_SNR_INCR_dB_Q7 << 8, psEncCtrl->sparseness_Q8 - ( 1 << 7 ) );
}
/*******************************/
/* Control bandwidth expansion */
/*******************************/
delta_Q16 = SKP_SMULWB( ( 1 << 16 ) - SKP_SMULBB( 3, psEncCtrl->coding_quality_Q14 ), LOW_RATE_BANDWIDTH_EXPANSION_DELTA_Q16 );
BWExp1_Q16 = BANDWIDTH_EXPANSION_Q16 - delta_Q16;
BWExp2_Q16 = BANDWIDTH_EXPANSION_Q16 + delta_Q16;
if( psEnc->sCmn.fs_kHz == 24 ) {
/* Less bandwidth expansion for super wideband */
BWExp1_Q16 = ( 1 << 16 ) - SKP_SMULWB( SWB_BANDWIDTH_EXPANSION_REDUCTION_Q16, ( 1 << 16 ) - BWExp1_Q16 );
BWExp2_Q16 = ( 1 << 16 ) - SKP_SMULWB( SWB_BANDWIDTH_EXPANSION_REDUCTION_Q16, ( 1 << 16 ) - BWExp2_Q16 );
}
/* BWExp1 will be applied after BWExp2, so make it relative */
BWExp1_Q16 = SKP_DIV32_16( SKP_LSHIFT( BWExp1_Q16, 14 ), SKP_RSHIFT( BWExp2_Q16, 2 ) );
/********************************************/
/* Compute noise shaping AR coefs and gains */
/********************************************/
sz = ( SKP_int )SKP_SMULBB( SHAPE_LPC_WIN_MS, psEnc->sCmn.fs_kHz );
for( k = 0; k < NB_SUBFR; k++ ) {
/* Apply window */
SKP_Silk_apply_sine_window( x_windowed, x_ptr, 0, SHAPE_LPC_WIN_MS * psEnc->sCmn.fs_kHz );
/* Update pointer: next LPC analysis block */
x_ptr += psEnc->sCmn.frame_length / NB_SUBFR;
/* Calculate auto correlation */
SKP_Silk_autocorr( auto_corr, &scale, x_windowed, sz, psEnc->sCmn.shapingLPCOrder + 1 );
/* Add white noise, as a fraction of energy */
auto_corr[0] = SKP_ADD32( auto_corr[0], SKP_max_32( SKP_SMULWB( SKP_RSHIFT( auto_corr[ 0 ], 4 ), SHAPE_WHITE_NOISE_FRACTION_Q20 ), 1 ) );
/* Calculate the reflection coefficients using schur */
nrg = SKP_Silk_schur64( refl_coef_Q16, auto_corr, psEnc->sCmn.shapingLPCOrder );
/* Convert reflection coefficients to prediction coefficients */
SKP_Silk_k2a_Q16( AR_Q24, refl_coef_Q16, psEnc->sCmn.shapingLPCOrder );
/* Bandwidth expansion for synthesis filter shaping */
SKP_Silk_bwexpander_32( AR_Q24, psEnc->sCmn.shapingLPCOrder, BWExp2_Q16 );
/* Make sure to fit in Q13 SKP_int16 */
SKP_Silk_LPC_fit( &psEncCtrl->AR2_Q13[ k * SHAPE_LPC_ORDER_MAX ], AR_Q24, 13, psEnc->sCmn.shapingLPCOrder );
/* Compute noise shaping filter coefficients */
SKP_memcpy(
&psEncCtrl->AR1_Q13[ k * SHAPE_LPC_ORDER_MAX ],
&psEncCtrl->AR2_Q13[ k * SHAPE_LPC_ORDER_MAX ],
psEnc->sCmn.shapingLPCOrder * sizeof( SKP_int16 ) );
/* Bandwidth expansion for analysis filter shaping */
SKP_assert( BWExp1_Q16 <= ( 1 << 16 ) ); // If ever breaking, use LPC_stabilize() in these cases to stay within range
SKP_Silk_bwexpander( &psEncCtrl->AR1_Q13[ k * SHAPE_LPC_ORDER_MAX ], psEnc->sCmn.shapingLPCOrder, BWExp1_Q16 );
/* Increase residual energy */
nrg = SKP_SMLAWB( nrg, SKP_RSHIFT( auto_corr[ 0 ], 8 ), SHAPE_MIN_ENERGY_RATIO_Q24 );
Qnrg = -scale; // range: -12...30
SKP_assert( Qnrg >= -12 );
SKP_assert( Qnrg <= 30 );
/* Make sure that Qnrg is an even number */
if( Qnrg & 1 ) {
Qnrg -= 1;
nrg >>= 1;
}
tmp32 = SKP_Silk_SQRT_APPROX( nrg );
Qnrg >>= 1; // range: -6...15
sqrt_nrg[ k ] = tmp32;
Qnrg_vec[ k ] = Qnrg;
psEncCtrl->Gains_Q16[ k ] = SKP_LSHIFT_SAT32( tmp32, 16 - Qnrg );
/* Ratio of prediction gains, in energy domain */
SKP_Silk_LPC_inverse_pred_gain_Q13( &pre_nrg_Q30, &psEncCtrl->AR2_Q13[ k * SHAPE_LPC_ORDER_MAX ], psEnc->sCmn.shapingLPCOrder );
SKP_Silk_LPC_inverse_pred_gain_Q13( &nrg, &psEncCtrl->AR1_Q13[ k * SHAPE_LPC_ORDER_MAX ], psEnc->sCmn.shapingLPCOrder );
lz = SKP_min_32( SKP_Silk_CLZ32( pre_nrg_Q30 ) - 1, 19 );
pre_nrg_Q30 = SKP_DIV32( SKP_LSHIFT( pre_nrg_Q30, lz ), SKP_RSHIFT( nrg, 20 - lz ) + 1 ); // Q20
pre_nrg_Q30 = SKP_RSHIFT( SKP_LSHIFT_SAT32( pre_nrg_Q30, 9 ), 1 ); /* Q28 */
psEncCtrl->GainsPre_Q14[ k ] = ( SKP_int )SKP_Silk_SQRT_APPROX( pre_nrg_Q30 );
}
