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#include "transient_detector.h"
#include <stdlib.h>
namespace NAtracDEnc {
static double calculateRMS(const double* in, uint32_t n) {
double s = 0;
for (uint32_t i = 0; i < n; i++) {
s += in[i] * in[i];
}
s /= n;
return sqrt(s);
}
void TTransientDetector::HPFilter(const double* in, double* out) {
const uint32_t firLen = 21;
static const double fircoef[] = {
-8.65163e-18 * 2.0, -0.00851586 * 2.0, -6.74764e-18 * 2.0, 0.0209036 * 2.0,
-3.36639e-17 * 2.0, -0.0438162 * 2.0, -1.54175e-17 * 2.0, 0.0931738 * 2.0,
-5.52212e-17 * 2.0, -0.313819 * 2.0
};
const uint32_t x = prevBufSz;
memcpy(HPFBuffer.data() + x, in, BlockSz * sizeof(double));
const double* inBuf = HPFBuffer.data();
for (int i = 0; i < BlockSz; ++i) {
double s = inBuf[i + 10];
double s2 = 0;
for (int j = 0; j < ((firLen - 1) / 2) - 1 ; j += 2) {
s += fircoef[j] * (inBuf[i + j] + inBuf[i + firLen - j]);
s2 += fircoef[j + 1] * (inBuf[i + j + 1] + inBuf[i + firLen - j - 1]);
}
out[i] = (s + s2)/2;
}
memcpy(HPFBuffer.data(), in + (BlockSz - x), x * sizeof(double));
}
bool TTransientDetector::Detect(const double* buf) {
const uint32_t nBlocksToAnalize = NShortBlocks + 1;
double* rmsPerShortBlock = reinterpret_cast<double*>(alloca(sizeof(double) * nBlocksToAnalize));
std::vector<double> filtered(BlockSz);
HPFilter(buf, filtered.data());
bool trans = false;
rmsPerShortBlock[0] = LastEnergy;
for (uint32_t i = 1; i < nBlocksToAnalize; ++i) {
rmsPerShortBlock[i] = 19.0 * log10(calculateRMS(&filtered[(i - 1) * ShortSz], ShortSz));
if (rmsPerShortBlock[i] - rmsPerShortBlock[i - 1] > 16) {
trans = true;
}
if (rmsPerShortBlock[i - 1] - rmsPerShortBlock[i] > 20) {
trans = true;
}
}
LastEnergy = rmsPerShortBlock[NShortBlocks];
return trans;
}
}
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