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Add a line per channel on spectral density graph (#265)
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* Work in progress

Signed-off-by: Dave Thaler <[email protected]>

* Fix -1 label on NodeEvents page

Signed-off-by: Dave Thaler <[email protected]>

* Split FrequencyInfo class into its own source file

Signed-off-by: Dave Thaler <[email protected]>

* More work in progress

Signed-off-by: Dave Thaler <[email protected]>

* Clean up unused onlyChannel params

Signed-off-by: Dave Thaler <[email protected]>

* Add a dataset per channel

Signed-off-by: Dave Thaler <[email protected]>

* Fixes

Signed-off-by: Dave Thaler <[email protected]>

* Address PR feedback from coderabbitai

Signed-off-by: Dave Thaler <[email protected]>

* Remove non-channel aggregate line for now

Signed-off-by: Dave Thaler <[email protected]>

* Cleanup and add a TODO to track down

Signed-off-by: Dave Thaler <[email protected]>

---------

Signed-off-by: Dave Thaler <[email protected]>
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@dthaler
dthaler authored Jan 30, 2025
1 parent 6b85613 commit b5fc4de
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Showing 6 changed files with 517 additions and 283 deletions.
2 changes: 1 addition & 1 deletion OrcanodeMonitor/Core/Fetcher.cs
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Expand Up @@ -438,9 +438,9 @@ public async static Task UpdateDataplicityDataAsync(OrcanodeMonitorContext conte
/// <returns>null on error, or JsonElement on success</returns>
private async static Task<JsonElement?> GetOrcasoundDataAsync(OrcanodeMonitorContext context, string site, ILogger logger)
{
string url = "https://" + site + _orcasoundFeedsUrlPath;
try
{
string url = "https://" + site + _orcasoundFeedsUrlPath;
string json = await _httpClient.GetStringAsync(url);
if (json.IsNullOrEmpty())
{
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231 changes: 0 additions & 231 deletions OrcanodeMonitor/Core/FfmpegCoreAnalyzer.cs
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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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