/* Upsample using a combination of allpass-based 2x upsampling and FIR interpolation */
void SKP_Silk_resampler_private_IIR_FIR(
void *SS, /* I/O: Resampler state */
SKP_int16 out[], /* O: Output signal */
const SKP_int16 in[], /* I: Input signal */
SKP_int32 inLen /* I: Number of input samples */
)
{
SKP_Silk_resampler_state_struct *S = (SKP_Silk_resampler_state_struct *)SS;
SKP_int32 nSamplesIn, table_index;
SKP_int32 max_index_Q16, index_Q16, index_increment_Q16, res_Q15;
SKP_int16 buf[ 2 * RESAMPLER_MAX_BATCH_SIZE_IN + RESAMPLER_ORDER_FIR_144 ];
SKP_int16 *buf_ptr;
/* Copy buffered samples to start of buffer */
SKP_memcpy( buf, S->sFIR, RESAMPLER_ORDER_FIR_144 * sizeof( SKP_int32 ) );
/* Iterate over blocks of frameSizeIn input samples */
index_increment_Q16 = S->invRatio_Q16;
while( 1 ) {
nSamplesIn = SKP_min( inLen, S->batchSize );
if( S->input2x == 1 ) {
/* Upsample 2x */
S->up2_function( S->sIIR, &buf[ RESAMPLER_ORDER_FIR_144 ], in, nSamplesIn );
} else {
/* Fourth-order ARMA filter */
SKP_Silk_resampler_private_ARMA4( S->sIIR, &buf[ RESAMPLER_ORDER_FIR_144 ], in, S->Coefs, nSamplesIn );
}
max_index_Q16 = SKP_LSHIFT32( nSamplesIn, 16 + S->input2x ); /* +1 if 2x upsampling */
/* Interpolate upsampled signal and store in output array */
for( index_Q16 = 0; index_Q16 < max_index_Q16; index_Q16 += index_increment_Q16 ) {
table_index = SKP_SMULWB( index_Q16 & 0xFFFF, 144 );
buf_ptr = &buf[ index_Q16 >> 16 ];
res_Q15 = SKP_SMULBB( buf_ptr[ 0 ], SKP_Silk_resampler_frac_FIR_144[ table_index ][ 0 ] );
res_Q15 = SKP_SMLABB( res_Q15, buf_ptr[ 1 ], SKP_Silk_resampler_frac_FIR_144[ table_index ][ 1 ] );
res_Q15 = SKP_SMLABB( res_Q15, buf_ptr[ 2 ], SKP_Silk_resampler_frac_FIR_144[ table_index ][ 2 ] );
res_Q15 = SKP_SMLABB( res_Q15, buf_ptr[ 3 ], SKP_Silk_resampler_frac_FIR_144[ 143 - table_index ][ 2 ] );
res_Q15 = SKP_SMLABB( res_Q15, buf_ptr[ 4 ], SKP_Silk_resampler_frac_FIR_144[ 143 - table_index ][ 1 ] );
res_Q15 = SKP_SMLABB( res_Q15, buf_ptr[ 5 ], SKP_Silk_resampler_frac_FIR_144[ 143 - table_index ][ 0 ] );
*out++ = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( res_Q15, 15 ) );
}
in += nSamplesIn;
inLen -= nSamplesIn;
if( inLen > 0 ) {
/* More iterations to do; copy last part of filtered signal to beginning of buffer */
SKP_memcpy( buf, &buf[ nSamplesIn << S->input2x ], RESAMPLER_ORDER_FIR_144 * sizeof( SKP_int32 ) );
} else {
break;
}
}
/* Copy last part of filtered signal to the state for the next call */
SKP_memcpy( S->sFIR, &buf[nSamplesIn << S->input2x ], RESAMPLER_ORDER_FIR_144 * sizeof( SKP_int32 ) );
}
/* Upsample using a combination of allpass-based 2x upsampling and FIR interpolation */
void SKP_Silk_resampler_private_IIR_FIR(
void *SS, /* I/O: Resampler state */
SKP_int16 out[], /* O: Output signal */
const SKP_int16 in[], /* I: Input signal */
SKP_int32 inLen /* I: Number of input samples */
)
{
SKP_Silk_resampler_state_struct *S = (SKP_Silk_resampler_state_struct *)SS;
SKP_int32 nSamplesIn;
SKP_int32 max_index_Q16, index_increment_Q16;
SKP_int16 buf[ 2 * RESAMPLER_MAX_BATCH_SIZE_IN + RESAMPLER_ORDER_FIR_144 ];
/* Copy buffered samples to start of buffer */
SKP_memcpy( buf, S->sFIR, RESAMPLER_ORDER_FIR_144 * sizeof( SKP_int32 ) );
/* Iterate over blocks of frameSizeIn input samples */
index_increment_Q16 = S->invRatio_Q16;
while( 1 ) {
nSamplesIn = SKP_min( inLen, S->batchSize );
if( S->input2x == 1 ) {
/* Upsample 2x */
S->up2_function( S->sIIR, &buf[ RESAMPLER_ORDER_FIR_144 ], in, nSamplesIn );
} else {
/* Fourth-order ARMA filter */
SKP_Silk_resampler_private_ARMA4( S->sIIR, &buf[ RESAMPLER_ORDER_FIR_144 ], in, S->Coefs, nSamplesIn );
}
max_index_Q16 = SKP_LSHIFT32( nSamplesIn, 16 + S->input2x ); /* +1 if 2x upsampling */
out = SKP_Silk_resampler_private_IIR_FIR_INTERPOL(out, buf, max_index_Q16, index_increment_Q16);
in += nSamplesIn;
inLen -= nSamplesIn;
if( inLen > 0 ) {
/* More iterations to do; copy last part of filtered signal to beginning of buffer */
SKP_memcpy( buf, &buf[ nSamplesIn << S->input2x ], RESAMPLER_ORDER_FIR_144 * sizeof( SKP_int32 ) );
} else {
break;
}
}
/* Copy last part of filtered signal to the state for the next call */
SKP_memcpy( S->sFIR, &buf[nSamplesIn << S->input2x ], RESAMPLER_ORDER_FIR_144 * sizeof( SKP_int32 ) );
}
