83 lines
2.4 KiB
C++
83 lines
2.4 KiB
C++
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#include <QtTest>
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#include <cmath>
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#include <vector>
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#include "vad.h"
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namespace {
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constexpr size_t kFrame = 320; // 20ms @16k
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constexpr double kPi = 3.14159265358979323846;
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// 生成 amplitude 幅值的 440Hz 正弦，用来模拟"有内容"的音频
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std::vector<float> tone(size_t samples, float amplitude)
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{
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std::vector<float> v(samples);
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for (size_t i = 0; i < samples; ++i) {
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v[i] = amplitude * (float) std::sin(2.0 * kPi * 440.0 * (double) i / 16000.0);
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}
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return v;
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}
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int countSpeech(lc::Vad & vad, const std::vector<float> & audio)
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{
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int speech = 0;
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for (size_t off = 0; off + kFrame <= audio.size(); off += kFrame) {
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if (vad.feed(audio.data() + off, kFrame)) ++speech;
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}
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return speech;
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}
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} // namespace
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// VAD 的回归测试。
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//
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// 关键教训：噪声底必须用"最小值跟踪"。曾经用均值跟踪，遇到本来就很轻的音频
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// （峰值 RMS 只有 0.03 量级的录音）会把阈值抬到语音电平之上，把绝大部分话音
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// 判成静音 —— 实时字幕于是每句都被切断。
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class TstVad : public QObject {
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Q_OBJECT
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private slots:
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void backgroundStaysSilent()
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{
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lc::Vad vad;
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const auto bg = tone(kFrame * 200, 0.001f); // rms ≈ 0.0007
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QCOMPARE(countSpeech(vad, bg), 0);
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}
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// 轻语音必须被判成语音：这里语音 rms ≈ 0.0028，
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// 旧的"均值跟踪 + 0.004 绝对下限"实现会全部漏掉。
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void quietSpeechIsDetected()
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{
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lc::Vad vad;
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const auto bg = tone(kFrame * 40, 0.001f); // rms ≈ 0.0007
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countSpeech(vad, bg);
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const auto sp = tone(kFrame * 100, 0.004f); // rms ≈ 0.0028
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const int speech = countSpeech(vad, sp);
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QVERIFY2(speech >= 95,
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qPrintable(QString("轻语音只被识别出 %1/100 帧").arg(speech)));
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}
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void loudSpeechIsDetected()
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{
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lc::Vad vad;
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const auto sp = tone(kFrame * 50, 0.2f);
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QVERIFY(countSpeech(vad, sp) >= 48);
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}
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void floorFollowsQuietInput()
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{
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lc::Vad vad;
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const auto bg = tone(kFrame * 200, 0.001f);
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countSpeech(vad, bg);
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// 噪声底应该已经下探到背景噪声量级，而不是停在初值
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QVERIFY2(vad.noiseFloor() < 0.002f,
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qPrintable(QString("噪声底仍为 %1").arg(vad.noiseFloor())));
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}
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};
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QTEST_MAIN(TstVad)
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#include "tst_vad.moc"
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