void SKP_Silk_LTP_analysis_filter_FIX(
SKP_int16 *LTP_res, /* O: LTP residual signal of length NB_SUBFR * ( pre_length + subfr_length ) */
const SKP_int16 *x, /* I: Pointer to input signal with at least max( pitchL ) preceeding samples */
const SKP_int16 LTPCoef_Q14[ LTP_ORDER * NB_SUBFR ],/* I: LTP_ORDER LTP coefficients for each NB_SUBFR subframe */
const SKP_int pitchL[ NB_SUBFR ], /* I: Pitch lag, one for each subframe */
const SKP_int32 invGains_Qxx[ NB_SUBFR ], /* I: Inverse quantization gains, one for each subframe */
const SKP_int Qxx, /* I: Inverse quantization gains Q domain */
const SKP_int subfr_length, /* I: Length of each subframe */
const SKP_int pre_length /* I: Length of the preceeding samples starting at &x[0] for each subframe */
)
{
const SKP_int16 *x_ptr, *x_lag_ptr;
SKP_int16 Btmp_Q14[ LTP_ORDER ];
SKP_int16 *LTP_res_ptr;
SKP_int k, i, j;
SKP_int32 LTP_est;
x_ptr = x;
LTP_res_ptr = LTP_res;
for( k = 0; k < NB_SUBFR; k++ ) {
x_lag_ptr = x_ptr - pitchL[ k ];
for( i = 0; i < LTP_ORDER; i++ ) {
Btmp_Q14[ i ] = LTPCoef_Q14[ k * LTP_ORDER + i ];
}
/* LTP analysis FIR filter */
for( i = 0; i < subfr_length + pre_length; i++ ) {
LTP_res_ptr[ i ] = x_ptr[ i ];
/* Long-term prediction */
LTP_est = SKP_SMULBB( x_lag_ptr[ LTP_ORDER / 2 ], Btmp_Q14[ 0 ] );
for( j = 1; j < LTP_ORDER; j++ ) {
LTP_est = SKP_SMLABB_ovflw( LTP_est, x_lag_ptr[ LTP_ORDER / 2 - j ], Btmp_Q14[ j ] );
}
LTP_est = SKP_RSHIFT_ROUND( LTP_est, 14 ); // round and -> Q0
/* Subtract long-term prediction */
LTP_res_ptr[ i ] = ( SKP_int16 )SKP_SAT16( ( SKP_int32 )x_ptr[ i ] - LTP_est );
/* Scale residual */
if( Qxx == 16 ) {
LTP_res_ptr[ i ] = SKP_SMULWB( invGains_Qxx[ k ], LTP_res_ptr[ i ] );
} else {
LTP_res_ptr[ i ] = ( SKP_int16 )SKP_CHECK_FIT16( SKP_RSHIFT64( SKP_SMULL( invGains_Qxx[ k ], LTP_res_ptr[ i ] ), Qxx ) );
}
x_lag_ptr++;
}
/* Update pointers */
LTP_res_ptr += subfr_length + pre_length;
x_ptr += subfr_length;
}
}
/* Copy and multiply a vector by a constant */
void silk_scale_copy_vector16(
SKP_int16 *data_out,
const SKP_int16 *data_in,
SKP_int32 gain_Q16, /* (I): gain in Q16 */
const SKP_int dataSize /* (I): length */
)
{
SKP_int i;
SKP_int32 tmp32;
for( i = 0; i < dataSize; i++ ) {
tmp32 = SKP_SMULWB( gain_Q16, data_in[ i ] );
data_out[ i ] = (SKP_int16)SKP_CHECK_FIT16( tmp32 );
}
}
/* Convert LSF parameters to AR prediction filter coefficients */
void SKP_Silk_NLSF2A_stable_FLP(
SKP_float *pAR, /* O LPC coefficients [ LPC_order ] */
const SKP_float *pNLSF, /* I NLSF vector [ LPC_order ] */
const SKP_int LPC_order /* I LPC order */
)
{
SKP_int i;
SKP_int NLSF_fix[ MAX_LPC_ORDER ];
SKP_int16 a_fix_Q12[ MAX_LPC_ORDER ];
for( i = 0; i < LPC_order; i++ ) {
NLSF_fix[ i ] = ( SKP_int )SKP_CHECK_FIT16( SKP_float2int( pNLSF[ i ] * 32768.0f ) );
}
SKP_Silk_NLSF2A_stable( a_fix_Q12, NLSF_fix, LPC_order );
for( i = 0; i < LPC_order; i++ ) {
pAR[ i ] = ( SKP_float )a_fix_Q12[ i ] / 4096.0f;
}
}
