refactor: fixing FFT Avx & simplifying VAD.

- Replace Ko-fi with AirTM for donations (since PayPal is unavailable in my region).

- Simplify Recorder and VAD components

- Remove VAD integration from Recorder component.

- Simplify VoiceActivityDetector for basic energy detection.

- Add modifier/analyzer management to Recorder.

feat(experimental): Introduce advanced VAD

- Add experimental VoiceActivityDetector with noise gate to Experimental namespace.

- Implement combined detection mode in advanced VAD.

- Add configuration options for advanced VAD.

- Move configurePlayer invocation after adding component
  to mixer to avoid potential issues.

- Move NoiseReductionModifier to Experimental namespace.
- Indicate it's under development and not stable.

- Introduce MathHelper.IsPowerOfTwo for power of two check.
- Add MathHelper.Lerp for linear interpolation.

- Optimize FFT algorithm by adding scalar implementation for
smaller sizes.
- Improve complex multiplication using AVX for
performance.

Author: LSXPrime

.github/FUNDING.yml

@@ -1,5 +1,4 @@
 # These are supported funding model platforms
 
-github: [LSXPrime]
-ko_fi: lsxprime
-custom: [https://app.binance.com/qr/dplk0837ff4256a64749a2b10dfe3ea5a0b9]
+github: LSXPrime
+custom: ["https://airtm.me/lsxprime", "https://app.binance.com/qr/dplk0837ff4256a64749a2b10dfe3ea5a0b9"]

.github/workflows/greetings.yml

@@ -0,0 +1,19 @@
+name: Greetings
+
+on: pull_request_target
+
+jobs:
+  greeting:
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+    steps:
+    - uses: actions/first-interaction@v1
+      with:
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
+        pr-message: |
+          Welcome to SoundFlow repository! We appreciate you taking the time to contribute. 
+          
+          We're excited to review your pull request and look forward to collaborating with you. Please let us know if you have any questions or need any assistance. 
+          
+          Thank you for your contribution!

.github/workflows/stale.yml

@@ -0,0 +1,39 @@
+# This workflow warns and then closes issues and PRs that have had no activity for a specified amount of time.
+#
+# You can adjust the behavior by modifying this file.
+# For more information, see:
+# https://github.com/actions/stale
+name: Mark stale issues and pull requests
+
+on:
+  schedule:
+  - cron: '44 8 * * *'
+
+jobs:
+  stale:
+
+    runs-on: ubuntu-latest
+    permissions:
+      issues: write
+      pull-requests: write
+
+    steps:
+    - uses: actions/stale@v5
+      with:
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
+        days-before-stale: 14
+        days-before-close: 7
+        stale-issue-message: |
+          This issue has been automatically marked as stale because it has not had recent activity. 
+          It will be closed if no further activity occurs. 
+          
+          If this issue is still relevant, please leave a comment indicating that you would like it to remain open. 
+          Thank you for your contributions.
+        stale-pr-message: |
+          This pull request has been automatically marked as stale because it has not had recent activity. 
+          It will be closed if no further activity occurs. 
+
+          If you are still working on this pull request, please leave a comment indicating that you would like it to remain open.
+          Thank you for your contributions. 
+        stale-issue-label: 'no-issue-activity'
+        stale-pr-label: 'no-pr-activity'

README.md

@@ -147,9 +147,10 @@ Beyond equipment, your contributions, no matter the size, help to:
 
 You can directly support SoundFlow and help me get essential headphones through:
 
-*   **Ko-fi:** For simple one-time donations or flexible recurring support.
+*   **AirTM:** For simple one-time donations with various payment options like Direct Bank Transfer (ACH), Debit / Credit Card via Moonpay, Stablecoins, and more than 500 banks and e-wallets.
+
+    [Donate using AirTM](https://airtm.me/lsxprime)
 
-    [![ko-fi](https://img.shields.io/badge/Ko--fi-F16061?style=for-the-badge&logo=ko-fi&logoColor=white)](https://ko-fi.com/lsxprime)
 
 *   **Binance Pay (Crypto - Preferred):**  Support with cryptocurrency via Binance Pay.
 

Samples/SoundFlow.SimplePlayer/ComponentTests.cs

@@ -2,9 +2,11 @@
 using SoundFlow.Backends.MiniAudio;
 using SoundFlow.Components;
 using SoundFlow.Enums;
+using SoundFlow.Experimental;
 using SoundFlow.Modifiers;
 using SoundFlow.Providers;
 using SoundFlow.Visualization;
+using VoiceActivityDetector = SoundFlow.Components.VoiceActivityDetector;
 
 namespace SoundFlow.SimplePlayer;
 
@@ -169,7 +171,7 @@ private static void TestVoiceActivityDetector()
 
         var microphoneProvider = new MicrophoneDataProvider();
         var soundPlayer = new SoundPlayer(microphoneProvider); // Play microphone input
-        soundPlayer.ConnectInput(vad); // VAD connected to microphone input
+        soundPlayer.AddAnalyzer(vad); // VAD connected to microphone input
         microphoneProvider.StartCapture();
         soundPlayer.Play();
 
@@ -186,7 +188,7 @@ private static void TestVoiceActivityDetector()
             // Ignore as it will throw exception if soundPlayer since it's seeking to 0 on stop but MicrophoneDataProvider doesn't support seeking
         }
 
-        soundPlayer.DisconnectInput(vad);
+        soundPlayer.RemoveAnalyzer(vad);
         microphoneProvider.Dispose();
 
         // Reinitialize audio engine for playback

Samples/SoundFlow.SimplePlayer/Program.cs

@@ -3,10 +3,12 @@
 using SoundFlow.Backends.MiniAudio;
 using SoundFlow.Components;
 using SoundFlow.Enums;
+using SoundFlow.Experimental;
 using SoundFlow.Interfaces;
 using SoundFlow.Modifiers;
 using SoundFlow.Providers;
 using SoundFlow.Visualization;
+using VoiceActivityDetector = SoundFlow.Components.VoiceActivityDetector;
 
 namespace SoundFlow.SimplePlayer;
 
@@ -101,7 +103,6 @@ private static void PlayAudio(ISoundDataProvider dataProvider, bool isSurround =
         SetOrCreateEngine();
         ISoundPlayer soundPlayer = isSurround ? new SurroundPlayer(dataProvider) : new SoundPlayer(dataProvider);
         SoundComponent component = isSurround ? (SurroundPlayer)soundPlayer : (SoundPlayer)soundPlayer;
-        configurePlayer?.Invoke(soundPlayer);
 
         if (modifiers != null)
         {
@@ -112,6 +113,8 @@ private static void PlayAudio(ISoundDataProvider dataProvider, bool isSurround =
         }
 
         Mixer.Master.AddComponent(component);
+        configurePlayer?.Invoke(soundPlayer);
+
         soundPlayer.Play();
 
         PlaybackControls(soundPlayer);
@@ -268,23 +271,13 @@ private static void MixedRecordAndPlayback()
     private static void RecordAndPlaybackAudio()
     {
         SetOrCreateEngine(Capability.Record, 48000);
-
-        var vad = new VoiceActivityDetector(
-            fftSize: 1024,
-            minHangoverFrames: 65,
-            maxHangoverFrames: 100,
-            minAttackFrames: 1,
-            maxAttackFrames: 5,
-            alpha: 0.95f,
-            spectralCentroidThreshold: 0.45f,
-            spectralFlatnessThreshold: 0.5f,
-            spectralFluxThreshold: 0.12f,
-            energyThreshold: 0.0002f
-        );
+        
+        var vad = new VoiceActivityDetector(1024, 3f);
 
         vad.SpeechDetected += isDetected => Console.WriteLine("Speech detected: " + isDetected);
 
-        using var recorder = new Recorder(RecordedFilePath, SampleFormat.F32, EncodingFormat.Wav, 48000, 2, vad);
+        using var recorder = new Recorder(RecordedFilePath, SampleFormat.F32, EncodingFormat.Wav, 48000);
+        recorder.AddAnalyzer(vad);
 
         Console.WriteLine("Recording started. Press 's' to stop, 'p' to pause/resume.");
         recorder.StartRecording();
@@ -371,27 +364,14 @@ private static void PlayAudioWithNoiseReduction()
             Console.WriteLine("File not found.");
             return;
         }
-
-        var vad = new VoiceActivityDetector(
-            fftSize: 512,
-            minHangoverFrames: 10,
-            maxHangoverFrames: 30,
-            minAttackFrames: 1,
-            maxAttackFrames: 5,
-            alpha: 0.95f,
-            spectralCentroidThreshold: 0.45f,
-            spectralFlatnessThreshold: 0.5f,
-            spectralFluxThreshold: 0.12f,
-            energyThreshold: 0.0002f
-        );
+        
 
         var noiseReductionModifier = new NoiseReductionModifier(
             fftSize: 2048,
             alpha: 3f,
             beta: 0.001f,
             gain: 1.2f,
             noiseFrames: 50
-           // vad: vad
         );
 
         PlayAudio(new StreamDataProvider(new FileStream(noisyFilePath, FileMode.Open, FileAccess.Read)), modifiers: new List<SoundModifier> { noiseReductionModifier });

Src/Components/Recorder.cs

@@ -2,12 +2,13 @@
 using SoundFlow.Enums;
 using SoundFlow.Interfaces;
 using SoundFlow.Exceptions;
+using System.Collections.ObjectModel;
 
 namespace SoundFlow.Components;
 
 /// <summary>
 /// Component for recording audio data, either to a file or via a callback.
-/// Supports various sample and encoding formats and can integrate with a Voice Activity Detector (VAD).
+/// Supports various sample and encoding formats and can integrate with <see cref="SoundModifier"/> and <see cref="AudioAnalyzer"/> components for real-time processing and analysis during recording.
 /// Implements the <see cref="IDisposable"/> interface to ensure resources are released properly.
 /// </summary>
 public class Recorder : IDisposable
@@ -50,7 +51,8 @@ public class Recorder : IDisposable
     public AudioProcessCallback? ProcessCallback;
 
     private ISoundEncoder? _encoder;
-    private readonly VoiceActivityDetector? _vad;
+    private readonly List<SoundModifier> _modifiers = [];
+    private readonly List<AudioAnalyzer> _analyzers = [];
 
     /// <summary>
     /// Initializes a new instance of the <see cref="Recorder"/> class to record audio to a file.
@@ -60,15 +62,12 @@ public class Recorder : IDisposable
     /// <param name="encodingFormat">The desired encoding format for the recorded audio file. Defaults to <see cref="EncodingFormat.Wav"/>.</param>
     /// <param name="sampleRate">The desired sample rate for recording, in samples per second. Defaults to 44100 Hz.</param>
     /// <param name="channels">The number of channels to record. Defaults to 2 (stereo).</param>
-    /// <param name="vad">An optional <see cref="VoiceActivityDetector"/> to use for voice activity detection during recording. Defaults to null.</param>
     public Recorder(string filePath,
         SampleFormat sampleFormat = SampleFormat.F32,
         EncodingFormat encodingFormat = EncodingFormat.Wav,
         int sampleRate = 44100,
-        int channels = 2,
-        VoiceActivityDetector? vad = null)
+        int channels = 2)
     {
-        _vad = vad;
         SampleFormat = sampleFormat;
         EncodingFormat = encodingFormat;
         FilePath = filePath;
@@ -84,25 +83,32 @@ public Recorder(string filePath,
     /// <param name="encodingFormat">The encoding format (primarily for internal use or if an encoder is manually managed). Defaults to <see cref="EncodingFormat.Wav"/>.</param>
     /// <param name="sampleRate">The desired sample rate for recording, in samples per second. Defaults to 44100 Hz.</param>
     /// <param name="channels">The number of channels to record. Defaults to 2 (stereo).</param>
-    /// <param name="vad">An optional <see cref="VoiceActivityDetector"/> to use for voice activity detection during recording. Defaults to null.</param>
     public Recorder(AudioProcessCallback callback,
         SampleFormat sampleFormat = SampleFormat.F32,
         EncodingFormat encodingFormat = EncodingFormat.Wav,
         int sampleRate = 44100,
-        int channels = 2,
-        VoiceActivityDetector? vad = null)
+        int channels = 2)
     {
         ProcessCallback = callback;
-        _vad = vad;
         SampleFormat = sampleFormat;
         EncodingFormat = encodingFormat;
         SampleRate = sampleRate;
         Channels = channels;
     }
 
+    /// <summary>
+    /// Gets a read-only list of <see cref="SoundModifier"/> components applied to the recorder.
+    /// </summary>
+    public ReadOnlyCollection<SoundModifier> Modifiers => _modifiers.AsReadOnly();
+
+    /// <summary>
+    /// Gets a read-only list of <see cref="AudioAnalyzer"/> components applied to the recorder.
+    /// </summary>
+    public ReadOnlyCollection<AudioAnalyzer> Analyzers => _analyzers.AsReadOnly();
+
     /// <summary>
     /// Starts the audio recording process.
-    /// If recording to a file, it initializes the audio encoder. If using a VAD, it starts monitoring for voice activity.
+    /// If recording to a file, it initializes the audio encoder.
     /// </summary>
     /// <exception cref="ArgumentException">Thrown if both <see cref="FilePath"/> and <see cref="ProcessCallback"/> are invalid (e.g., <see cref="FilePath"/> is null or empty and <see cref="ProcessCallback"/> is null).</exception>
     /// <exception cref="BackendException">Thrown if creating the audio encoder fails when recording to a file.</exception>
@@ -124,17 +130,6 @@ public void StartRecording()
 
         AudioEngine.OnAudioProcessed += OnOnAudioProcessed;
         State = PlaybackState.Playing;
-
-        if (_vad != null)
-        {
-            _vad.SpeechDetected += isDetected =>
-            {
-                if (isDetected)
-                    ResumeRecording();
-                else
-                    PauseRecording();
-            };
-        }
     }
 
     /// <summary>
@@ -179,19 +174,70 @@ public void StopRecording()
         State = PlaybackState.Stopped;
     }
 
+    /// <summary>
+    /// Adds a <see cref="SoundModifier"/> to the recording pipeline.
+    /// Modifiers are applied to the audio data before encoding or processing via callback.
+    /// </summary>
+    /// <param name="modifier">The modifier to add.</param>
+    public void AddModifier(SoundModifier modifier)
+    {
+        _modifiers.Add(modifier);
+    }
+
+    /// <summary>
+    /// Removes a <see cref="SoundModifier"/> from the recording pipeline.
+    /// </summary>
+    /// <param name="modifier">The modifier to remove.</param>
+    public void RemoveModifier(SoundModifier modifier)
+    {
+        _modifiers.Remove(modifier);
+    }
+
+    /// <summary>
+    /// Adds an <see cref="AudioAnalyzer"/> to the recording pipeline.
+    /// Analyzers can be used to process and extract data from the audio during recording.
+    /// </summary>
+    /// <param name="analyzer">The analyzer to add.</param>
+    public void AddAnalyzer(AudioAnalyzer analyzer)
+    {
+        _analyzers.Add(analyzer);
+    }
+
+    /// <summary>
+    /// Removes an <see cref="AudioAnalyzer"/> from the recording pipeline.
+    /// </summary>
+    /// <param name="analyzer">The analyzer to remove.</param>
+    public void RemoveAnalyzer(AudioAnalyzer analyzer)
+    {
+        _analyzers.Remove(analyzer);
+    }
+
     /// <summary>
     /// Handles the audio processed event from the audio engine.
     /// This method is invoked by the audio engine when new audio samples are available.
-    /// It processes the samples through the VAD (if enabled), checks the current state, invokes the <see cref="ProcessCallback"/> (if set), and encodes the samples using the <see cref="_encoder"/> (if recording to a file).
+    /// It processes the samples through the added <see cref="SoundModifier"/> and <see cref="AudioAnalyzer"/> components, checks the current state, invokes the <see cref="ProcessCallback"/> (if set), and encodes the samples using the <see cref="_encoder"/> (if recording to a file).
     /// </summary>
     /// <param name="samples">A span containing the audio samples to process.</param>
     /// <param name="capability">The audio capability associated with the processed samples (e.g., input or output).</param>
     private void OnOnAudioProcessed(Span<float> samples, Capability capability)
     {
-        _vad?.Process(samples);
         if (State != PlaybackState.Playing)
             return;
 
+        // Apply modifiers
+        foreach (var modifier in _modifiers)
+        {
+            if (modifier.Enabled)
+                modifier.Process(samples);
+        }
+
+        // Process analyzers
+        foreach (var analyzer in _analyzers)
+        {
+             analyzer.Process(samples);
+        }
+
+        // Pass samples
         ProcessCallback?.Invoke(samples, capability);
         _encoder?.Encode(samples);
     }
@@ -202,6 +248,8 @@ public void Dispose()
         StopRecording();
         AudioEngine.OnAudioProcessed -= OnOnAudioProcessed;
         ProcessCallback = null;
+        _modifiers.Clear();
+        _analyzers.Clear();
         GC.SuppressFinalize(this);
     }
 }