ref: 4923e0b8fa44d5b3118f0837be12d406202106f7
dir: /silk/fixed/LTP_scale_ctrl_FIX.c/
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#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "main_FIX.h"
/* Calculation of LTP state scaling */
void silk_LTP_scale_ctrl_FIX(
silk_encoder_state_FIX *psEnc, /* I/O encoder state */
silk_encoder_control_FIX *psEncCtrl, /* I/O encoder control */
opus_int condCoding /* I The type of conditional coding to use */
)
{
opus_int round_loss;
if( condCoding == CODE_INDEPENDENTLY ) {
/* Only scale if first frame in packet */
round_loss = psEnc->sCmn.PacketLoss_perc * psEnc->sCmn.nFramesPerPacket;
if ( psEnc->sCmn.LBRR_flag ) {
/* LBRR reduces the effective loss. In practice, it does not square the loss because
losses aren't independent, but that still seems to work best. We also never go below 2%. */
round_loss = 2 + silk_SMULBB( round_loss, round_loss ) / 100;
}
psEnc->sCmn.indices.LTP_scaleIndex = silk_SMULBB( psEncCtrl->LTPredCodGain_Q7, round_loss ) > silk_log2lin( 128*7 + 2900-psEnc->sCmn.SNR_dB_Q7 );
psEnc->sCmn.indices.LTP_scaleIndex += silk_SMULBB( psEncCtrl->LTPredCodGain_Q7, round_loss ) > silk_log2lin( 128*7 + 3900-psEnc->sCmn.SNR_dB_Q7 );
} else {
/* Default is minimum scaling */
psEnc->sCmn.indices.LTP_scaleIndex = 0;
}
psEncCtrl->LTP_scale_Q14 = silk_LTPScales_table_Q14[ psEnc->sCmn.indices.LTP_scaleIndex ];
}