ref: fd1a5db140d51e7188e5126db2edc0ab923cfa8c
dir: /src_common/SKP_Silk_detect_SWB_input.c/
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/*
* Detect SWB input by measuring energy above 8 kHz.
*/
#include "SKP_Silk_main.h"
void SKP_Silk_detect_SWB_input(
SKP_Silk_detect_SWB_state *psSWBdetect, /* (I/O) encoder state */
const SKP_int16 samplesIn[], /* (I) input to encoder */
SKP_int nSamplesIn /* (I) length of input */
)
{
SKP_int HP_8_kHz_len, i, shift;
SKP_int16 in_HP_8_kHz[ MAX_FRAME_LENGTH ];
SKP_int32 energy_32;
/* High pass filter with cutoff at 8 khz */
HP_8_kHz_len = SKP_min_int( nSamplesIn, MAX_FRAME_LENGTH );
HP_8_kHz_len = SKP_max_int( HP_8_kHz_len, 0 );
/* Cutoff around 9 khz */
/* A = conv(conv([8192,14613, 6868], [8192,12883, 7337]), [8192,11586, 7911]); */
/* B = conv(conv([575, -948, 575], [575, -221, 575]), [575, 104, 575]); */
SKP_Silk_biquad( samplesIn, SKP_Silk_SWB_detect_B_HP_Q13[ 0 ], SKP_Silk_SWB_detect_A_HP_Q13[ 0 ],
psSWBdetect->S_HP_8_kHz[ 0 ], in_HP_8_kHz, HP_8_kHz_len );
for( i = 1; i < NB_SOS; i++ ) {
SKP_Silk_biquad( in_HP_8_kHz, SKP_Silk_SWB_detect_B_HP_Q13[ i ], SKP_Silk_SWB_detect_A_HP_Q13[ i ],
psSWBdetect->S_HP_8_kHz[ i ], in_HP_8_kHz, HP_8_kHz_len );
}
/* Calculate energy in HP signal */
SKP_Silk_sum_sqr_shift( &energy_32, &shift, in_HP_8_kHz, HP_8_kHz_len );
/* Count concecutive samples above threshold, after adjusting threshold for number of input samples and shift */
if( energy_32 > SKP_RSHIFT( SKP_SMULBB( HP_8_KHZ_THRES, HP_8_kHz_len ), shift ) ) {
psSWBdetect->ConsecSmplsAboveThres += nSamplesIn;
if( psSWBdetect->ConsecSmplsAboveThres > CONCEC_SWB_SMPLS_THRES ) {
psSWBdetect->SWB_detected = 1;
}
} else {
psSWBdetect->ConsecSmplsAboveThres -= nSamplesIn;
psSWBdetect->ConsecSmplsAboveThres = SKP_max( psSWBdetect->ConsecSmplsAboveThres, 0 );
}
/* If sufficient speech activity and no SWB detected, we detect the signal as being WB */
if( ( psSWBdetect->ActiveSpeech_ms > WB_DETECT_ACTIVE_SPEECH_MS_THRES ) && ( psSWBdetect->SWB_detected == 0 ) ) {
psSWBdetect->WB_detected = 1;
}
}