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Add a line per channel on spectral density graph #265

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merged 10 commits into from
Jan 30, 2025
Merged

Add a line per channel on spectral density graph #265

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f0227ed
Work in progress
dthaler Jan 22, 2025
031d244
Fix -1 label on NodeEvents page
dthaler Jan 22, 2025
c989462
Split FrequencyInfo class into its own source file
dthaler Jan 22, 2025
3d3f0c2
More work in progress
dthaler Jan 22, 2025
c818ca8
Clean up unused onlyChannel params
dthaler Jan 22, 2025
5c7bd37
Add a dataset per channel
dthaler Jan 29, 2025
421768e
Fixes
dthaler Jan 29, 2025
a3b79cf
Address PR feedback from coderabbitai
dthaler Jan 29, 2025
6dbe0dd
Remove non-channel aggregate line for now
dthaler Jan 29, 2025
46ded52
Cleanup and add a TODO to track down
dthaler Jan 29, 2025
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231 changes: 0 additions & 231 deletions OrcanodeMonitor/Core/FfmpegCoreAnalyzer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,242 +2,11 @@
// SPDX-License-Identifier: MIT
using FFMpegCore;
using FFMpegCore.Pipes;
using MathNet.Numerics.IntegralTransforms;
using NAudio.Wave;
using OrcanodeMonitor.Models;
using System.Diagnostics;
using System.Numerics;

namespace OrcanodeMonitor.Core
{
public class FrequencyInfo
{
public FrequencyInfo(float[] data, int sampleRate, int channels, OrcanodeOnlineStatus oldStatus)
{
FrequencyMagnitudes = ComputeFrequencyMagnitudes(data, sampleRate, channels);
Status = GetStatus(oldStatus);
}

private static Dictionary<double, double> ComputeFrequencyMagnitudes(float[] data, int sampleRate, int channels)
{
var result = new Dictionary<double, double>();
int n = data.Length / channels;

// Create an array of complex data for each channel.
Complex[][] complexData = new Complex[channels][];
for (int ch = 0; ch < channels; ch++)
{
complexData[ch] = new Complex[n];
}

// Populate the complex arrays with channel data.
for (int i = 0; i < n; i++)
{
for (int ch = 0; ch < channels; ch++)
{
complexData[ch][i] = new Complex(data[i * channels + ch], 0);
}
}

// Perform Fourier transform for each channel.
var channelResults = new List<Dictionary<double, double>>();
for (int ch = 0; ch < channels; ch++)
{
Fourier.Forward(complexData[ch], FourierOptions.Matlab);
var channelResult = new Dictionary<double, double>();
for (int i = 0; i < n / 2; i++)
{
double magnitude = complexData[ch][i].Magnitude;
double frequency = (((double)i) * sampleRate) / n;
channelResult[frequency] = magnitude;
}
channelResults.Add(channelResult);
}

// Combine results from all channels.
foreach (var channelResult in channelResults)
{
foreach (var kvp in channelResult)
{
if (!result.ContainsKey(kvp.Key))
{
result[kvp.Key] = 0;
}
if (result[kvp.Key] < kvp.Value)
{
result[kvp.Key] = kvp.Value;
}
}
}

return result;
}

// We consider anything above this average magnitude as not silence.
const double _defaultMaxSilenceMagnitude = 20.0;
public static double MaxSilenceMagnitude
{
get
{
string? maxSilenceMagnitudeString = Environment.GetEnvironmentVariable("ORCASOUND_MAX_SILENCE_MAGNITUDE");
double maxSilenceMagnitude = double.TryParse(maxSilenceMagnitudeString, out var magnitude) ? magnitude : _defaultMaxSilenceMagnitude;
return maxSilenceMagnitude;
}
}

// We consider anything below this average magnitude as silence.
const double _defaultMinNoiseMagnitude = 15.0;
public static double MinNoiseMagnitude
{
get
{
string? minNoiseMagnitudeString = Environment.GetEnvironmentVariable("ORCASOUND_MIN_NOISE_MAGNITUDE");
double minNoiseMagnitude = double.TryParse(minNoiseMagnitudeString, out var magnitude) ? magnitude : _defaultMinNoiseMagnitude;
return minNoiseMagnitude;
}
}

// Minimum ratio of magnitude outside the hum range to magnitude
// within the hum range. So far the max in a known-unintelligible
// sample is 53% and the min in a known-good sample is 114%.
const double _defaultMinSignalPercent = 100;
private static double MinSignalRatio
{
get
{
string? minSignalPercentString = Environment.GetEnvironmentVariable("ORCASOUND_MIN_INTELLIGIBLE_SIGNAL_PERCENT");
double minSignalPercent = double.TryParse(minSignalPercentString, out var percent) ? percent : _defaultMinSignalPercent;
return minSignalPercent / 100.0;
}
}

public Dictionary<double, double> FrequencyMagnitudes { get; }
public OrcanodeOnlineStatus Status { get; }

/// <summary>
/// URL at which the original audio sample can be found.
/// </summary>
public string AudioSampleUrl { get; set; } = string.Empty;

public double MaxMagnitude => FrequencyMagnitudes.Values.Max();

// Microphone audio hum typically falls within the 50 Hz or 60 Hz
// range. This hum is often caused by electrical interference from
// power lines and other electronic devices.
const double HumFrequency1 = 50.0; // Hz
const double HumFrequency2 = 60.0; // Hz
private static bool IsHumFrequency(double frequency, double humFrequency)
{
Debug.Assert(frequency >= 0.0);
Debug.Assert(humFrequency >= 0.0);
const double tolerance = 1.0;
double remainder = frequency % humFrequency;
return (remainder < tolerance || remainder > (humFrequency - tolerance));
}

public static bool IsHumFrequency(double frequency) => IsHumFrequency(frequency, HumFrequency1) || IsHumFrequency(frequency, HumFrequency2);

/// <summary>
/// Find the maximum magnitude outside the audio hum range.
/// </summary>
/// <returns>Magnitude</returns>
public double GetMaxNonHumMagnitude()
{
double maxNonHumMagnitude = 0;
foreach (var pair in FrequencyMagnitudes)
{
double frequency = pair.Key;
double magnitude = pair.Value;
if (!IsHumFrequency(frequency))
{
if (maxNonHumMagnitude < magnitude)
{
maxNonHumMagnitude = magnitude;
}
}
}
return maxNonHumMagnitude;
}

/// <summary>
/// Find the total magnitude outside the audio hum range.
/// </summary>
/// <returns>Magnitude</returns>
public double GetTotalNonHumMagnitude()
{
double totalNonHumMagnitude = 0;
foreach (var pair in FrequencyMagnitudes)
{
double frequency = pair.Key;
double magnitude = pair.Value;
if (!IsHumFrequency(frequency))
{
if (magnitude > MinNoiseMagnitude)
{
totalNonHumMagnitude += magnitude;
}
}
}
return totalNonHumMagnitude;
}

/// <summary>
/// Find the total magnitude of the audio hum range.
/// </summary>
/// <returns>Magnitude</returns>
public double GetTotalHumMagnitude()
{
double totalHumMagnitude = 0;
foreach (var pair in FrequencyMagnitudes)
{
double frequency = pair.Key;
double magnitude = pair.Value;
if (IsHumFrequency(frequency))
{
if (magnitude > MinNoiseMagnitude)
{
totalHumMagnitude += magnitude;
}
}
}
return totalHumMagnitude;
}

private OrcanodeOnlineStatus GetStatus(OrcanodeOnlineStatus oldStatus)
{
double max = MaxMagnitude;
if (max < MinNoiseMagnitude)
{
// File contains mostly silence across all frequencies.
return OrcanodeOnlineStatus.Silent;
}

if ((max <= MaxSilenceMagnitude) && (oldStatus == OrcanodeOnlineStatus.Silent))
{
// In between the min and max silence range, so keep previous status.
return oldStatus;
}

// Find the total magnitude outside the audio hum range.
if (GetMaxNonHumMagnitude() < MinNoiseMagnitude)
{
// Just silence outside the hum range, no signal.
return OrcanodeOnlineStatus.Unintelligible;
}

double totalNonHumMagnitude = GetTotalNonHumMagnitude();
double totalHumMagnitude = GetTotalHumMagnitude();
if (totalNonHumMagnitude / totalHumMagnitude < MinSignalRatio)
{
// Essentially just silence outside the hum range, no signal.
return OrcanodeOnlineStatus.Unintelligible;
}

// Signal outside the hum range.
return OrcanodeOnlineStatus.Online;
}
}

public class FfmpegCoreAnalyzer
{
/// <summary>
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