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/*
* This file is part of AtracDEnc.
*
* AtracDEnc is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* AtracDEnc is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with AtracDEnc; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "transient_detector.h"
#include <stdlib.h>
#include <string.h>
#include <cmath>
#include <cassert>
#include <iostream>
namespace NAtracDEnc {
using std::vector;
static TFloat calculateRMS(const TFloat* in, uint32_t n) {
TFloat s = 0;
for (uint32_t i = 0; i < n; i++) {
s += (in[i] * in[i]);
}
s /= n;
return sqrt(s);
}
static TFloat calculatePeak(const TFloat* in, uint32_t n) {
TFloat s = 0;
for (uint32_t i = 0; i < n; i++) {
TFloat absVal = std::abs(in[i]);
if (absVal > s)
s = absVal;
}
return s;
}
void TTransientDetector::HPFilter(const TFloat* in, TFloat* out) {
static const TFloat 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
};
memcpy(HPFBuffer.data() + PrevBufSz, in, BlockSz * sizeof(double));
const double* inBuf = HPFBuffer.data();
for (size_t i = 0; i < BlockSz; ++i) {
double s = inBuf[i + 10];
double s2 = 0;
for (size_t 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 - PrevBufSz), PrevBufSz * sizeof(double));
}
bool TTransientDetector::Detect(const TFloat* buf) {
const uint32_t nBlocksToAnalize = NShortBlocks + 1;
TFloat* rmsPerShortBlock = reinterpret_cast<TFloat*>(alloca(sizeof(TFloat) * nBlocksToAnalize));
std::vector<TFloat> 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;
LastTransientPos = i;
}
if (rmsPerShortBlock[i - 1] - rmsPerShortBlock[i] > 20) {
trans = true;
LastTransientPos = i;
}
}
LastEnergy = rmsPerShortBlock[NShortBlocks];
return trans;
}
std::vector<TFloat> AnalyzeGain(const TFloat* in, const uint32_t len, const uint32_t maxPoints, bool useRms) {
vector<TFloat> res;
const uint32_t step = len / maxPoints;
for (uint32_t pos = 0; pos < len; pos += step) {
TFloat rms = useRms ? calculateRMS(in + pos, step) : calculatePeak(in + pos, step);
res.emplace_back(rms);
}
return res;
}
} //namespace NAtracDEnc
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