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ggwave : switch from uint8_t -> uint16_t for fixed length decoding

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uint8_t does not work so well for some reason. Probably we lose
precission, although it's not obvious why
This commit is contained in:
Georgi Gerganov
2022-06-04 10:23:13 +03:00
parent 33581cf029
commit 3fba71926d
1 changed files with 15 additions and 5 deletions
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20
src/ggwave.cpp
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@@ -365,7 +365,7 @@ struct GGWave::Rx {
int historyIdFixed = 0; int historyIdFixed = 0;
std::vector<std::vector<uint8_t>> spectrumHistoryFixed; std::vector<std::vector<uint16_t>> spectrumHistoryFixed;
std::vector<uint8_t> detectedBins; std::vector<uint8_t> detectedBins;
std::vector<uint8_t> detectedTones; std::vector<uint8_t> detectedTones;
}; };
@@ -1716,10 +1716,20 @@ void GGWave::decode_fixed() {
amax = std::max(amax, m_rx->sampleSpectrum[i]); amax = std::max(amax, m_rx->sampleSpectrum[i]);
} }
// float -> uint8_t // original, floating-point version
//m_rx->spectrumHistoryFixed[m_rx->historyIdFixed] = m_rx->sampleSpectrum; //m_rx->spectrumHistoryFixed[m_rx->historyIdFixed] = m_rx->sampleSpectrum;
// in theory, using uint8_t should work alsmost the same and save 4 times the memory, but for some resone
// the result are not as good as with the floating-point version
// float -> uint8_t
//for (int i = 0; i < m_samplesPerFrame; ++i) {
// m_rx->spectrumHistoryFixed[m_rx->historyIdFixed][i] = std::min(255.0, std::max(0.0, round(m_rx->sampleSpectrum[i]/amax*255.0f)));
//}
// hence we opt for the uint16_t version, saving 2 times the memory and getting similar results as the floating-point version
// float -> uint16_t
for (int i = 0; i < m_samplesPerFrame; ++i) { for (int i = 0; i < m_samplesPerFrame; ++i) {
m_rx->spectrumHistoryFixed[m_rx->historyIdFixed][i] = std::min(255.0, std::max(0.0, round(m_rx->sampleSpectrum[i]/amax*255.0f))); m_rx->spectrumHistoryFixed[m_rx->historyIdFixed][i] = std::min(65535.0, std::max(0.0, round(m_rx->sampleSpectrum[i]/amax*65535.0f)));
} }
if (++m_rx->historyIdFixed >= (int) m_rx->spectrumHistoryFixed.size()) { if (++m_rx->historyIdFixed >= (int) m_rx->spectrumHistoryFixed.size()) {
@@ -1771,8 +1781,8 @@ void GGWave::decode_fixed() {
int f0bin = -1; int f0bin = -1;
int f1bin = -1; int f1bin = -1;
double f0max = 0.0; double f0max = -1.0;
double f1max = 0.0; double f1max = -1.0;
for (int b = 0; b < 16; ++b) { for (int b = 0; b < 16; ++b) {
{ {