2016-03-15 21:52:31 +00:00
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#include "voiceActivityDetection.h"
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#include <audio/DCOffset.h>
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#include <audio/SampleRateConverter.h>
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#include <boost/optional/optional.hpp>
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#include <logging.h>
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using std::numeric_limits;
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using std::vector;
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using boost::optional;
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float getRMS(AudioStream& audioStream, int maxSampleCount = numeric_limits<int>::max()) {
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double sum = 0;
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int sampleCount;
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for (sampleCount = 0; sampleCount < maxSampleCount && !audioStream.endOfStream(); sampleCount++) {
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sum += std::pow(static_cast<double>(audioStream.readSample()), 2);
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}
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return sampleCount > 0 ? static_cast<float>(std::sqrt(sum / sampleCount)) : 0.0f;
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}
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2016-04-09 20:07:25 +00:00
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Timeline<bool> detectVoiceActivity(std::unique_ptr<AudioStream> audioStream) {
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2016-03-15 21:52:31 +00:00
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// Make sure audio stream has no DC offset
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audioStream = removeDCOffset(std::move(audioStream));
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// Resample to remove noise
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constexpr int maxFrequency = 1000;
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constexpr int sampleRate = 2 * maxFrequency;
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audioStream = convertSampleRate(std::move(audioStream), sampleRate);
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2016-04-09 20:07:25 +00:00
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// Detect activity
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const float rms = getRMS(*audioStream->clone(true));
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const float cutoff = rms / 50;
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Timeline<bool> activity(audioStream->getTruncatedRange());
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for (centiseconds time = centiseconds::zero(); !audioStream->endOfStream(); ++time) {
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float currentRMS = getRMS(*audioStream, sampleRate / 100);
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bool active = currentRMS > cutoff;
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2016-03-15 21:52:31 +00:00
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if (active) {
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2016-04-09 20:07:25 +00:00
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activity[time] = true;
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2016-03-15 21:52:31 +00:00
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}
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}
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2016-04-09 20:07:25 +00:00
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// Fill small gaps in activity
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const centiseconds maxGap(10);
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for (const auto& element : Timeline<bool>(activity)) {
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if (!element.getValue() && element.getLength() <= maxGap) {
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activity.set(static_cast<TimeRange>(element), true);
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}
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}
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// Log
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for (const auto& element : activity) {
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2016-04-13 20:37:39 +00:00
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logging::logTimedEvent("utterance", static_cast<TimeRange>(element), std::string());
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2016-03-15 21:52:31 +00:00
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}
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2016-04-09 20:07:25 +00:00
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return activity;
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2016-03-15 21:52:31 +00:00
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}
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