Improve unintelligibility algorithm (#139)

Signed-off-by: Dave Thaler <[email protected]>
orcasound · Sep 29, 2024 · 036b51c · 036b51c
1 parent 7653dde
commit 036b51c
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Showing 4 changed files with 9 additions and 4 deletions.
diff --git a/OrcanodeMonitor/Core/FfmpegCoreAnalyzer.cs b/OrcanodeMonitor/Core/FfmpegCoreAnalyzer.cs
@@ -11,9 +11,12 @@ namespace OrcanodeMonitor.Core
 {
     public class FfmpegCoreAnalyzer
     {
-        // We consider anything below this amplitude as silence.
+        // We consider anything below this average amplitude as silence.
         const double MaxSilenceAmplitude = 20.0;
 
+        // We consider anything above this frequency amplitude as signal.
+        const double MinSignalAmplitude = 200.0;
+
         // Microphone audio hum typically falls within the 50 Hz to 60 Hz
         // range. This hum is often caused by electrical interference from
         // power lines and other electronic devices.
@@ -40,15 +43,15 @@ private static OrcanodeOnlineStatus AnalyzeFrequencies(float[] data, int sampleR
 
             // Look for signal in frequencies other than the audio hum range.
             double halfOfMax = amplitudes.Max() / 2.0;
-            var majorOtherIndices = new List<int>();
+            var majorOtherIndices = new Dictionary<double, double>();
             for (int i = 0; i < amplitudes.Length; i++)
             {
-                if (amplitudes[i] > halfOfMax)
+                if (amplitudes[i] > MinSignalAmplitude)
                 {
                     double frequency = (((double)i) * sampleRate) / n;
                     if (frequency < MinHumFrequency || frequency > MaxHumFrequency)
                     {
-                        majorOtherIndices.Add(i);
+                        majorOtherIndices[frequency] = amplitudes[i];
                     }
                 }
             }

diff --git a/Test/UnintelligibilityTests.cs b/Test/UnintelligibilityTests.cs
@@ -47,6 +47,8 @@ public async Task TestUnintelligibleSample()
         [TestMethod]
         public async Task TestNormalSample()
         {
+            await TestSampleAsync("normal\\live2649.ts", OrcanodeOnlineStatus.Online);
+            await TestSampleAsync("normal\\live2289.ts", OrcanodeOnlineStatus.Online);
             await TestSampleAsync("normal\\live385.ts", OrcanodeOnlineStatus.Online);
             await TestSampleAsync("normal\\live839.ts", OrcanodeOnlineStatus.Online);
             await TestSampleAsync("normal\\live1184.ts", OrcanodeOnlineStatus.Online);

diff --git a/Test/samples/normal/live2289.ts b/Test/samples/normal/live2289.ts
diff --git a/Test/samples/normal/live2649.ts b/Test/samples/normal/live2649.ts