WIP: waveform visualization

Source/AudioFileAnalyzer.cs

@@ -0,0 +1,88 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using Godot;
+using NAudio.Wave;
+
+namespace AudioEditor;
+
+public partial class AudioFileAnalyzer : Node
+{
+    public static AudioFileAnalyzer Instance { get; private set; }
+
+    public override void _Ready()
+    {
+        base._Ready();
+        Instance = this;
+    }
+
+    public void AnalyzeFile(string path, out WaveformInfo waveformInfo)
+    {
+        waveformInfo = new();
+
+        if (_waveformInfoCache.ContainsKey(path))
+        {
+            waveformInfo = _waveformInfoCache[path];
+            return;
+        }
+
+        var ext = Path.GetExtension(path);
+
+        switch (ext)
+        {
+            case ".wav":
+                GD.Print("Analyzing a WAV file...");
+                AnalyzeWav(path, out waveformInfo);
+                break;
+            default:
+                GD.Print($"Format {ext} is not supported!");
+                break;
+        }
+
+        _waveformInfoCache.Add(path, waveformInfo);
+    }
+
+    public bool TryGetFromCache(string path, out WaveformInfo waveformInfo)
+    {
+        return _waveformInfoCache.TryGetValue(path, out waveformInfo);
+    }
+
+    private void AnalyzeWav(string path, out WaveformInfo waveformInfo)
+    {
+        waveformInfo = new WaveformInfo();
+        using (var reader = new WaveFileReader(path))
+        {
+            waveformInfo.Length = reader.TotalTime;
+            waveformInfo.SampleRate = reader.WaveFormat.SampleRate;
+
+            long sampleCount = reader.Length / reader.WaveFormat.BlockAlign;
+            waveformInfo.Samples = new float[sampleCount];
+
+            // Render the waveform
+            byte[] buffer = new byte[reader.WaveFormat.BlockAlign];
+            for (int i = 0; i < sampleCount; i++)
+            {
+                int sampleIndex = i * reader.WaveFormat.BlockAlign;
+                while (reader.Position < reader.Length)
+                {
+                    // Read the raw bytes for the current sample
+                    reader.Read(buffer, 0, buffer.Length);
+
+                    // Convert the byte array to a 16-bit sample (assuming 16-bit PCM)
+                    short sample = BitConverter.ToInt16(buffer, 0);  // Assuming 16-bit signed samples
+
+                    waveformInfo.Samples[sampleIndex++] = (float)sample / short.MaxValue;
+                }
+            }
+        }
+    }
+
+    private Dictionary<string, WaveformInfo> _waveformInfoCache = new();
+}
+
+public class WaveformInfo
+{
+    public int SampleRate { get; set; }
+    public TimeSpan Length { get; set; }
+    public float[] Samples { get; set; }
+}