fix: moved the OffsetPosition property to the Sound class to work correctly

src/Beutl.Engine/Audio/Graph/AudioContext.cs

@@ -144,8 +144,6 @@ public GainNode CreateGainNode(IProperty<float> gain)
     public ShiftNode CreateShiftNode(TimeSpan shift)
     {
         ThrowIfDisposed();
-        if(shift < TimeSpan.Zero)
-            throw new ArgumentOutOfRangeException(nameof(shift), "Shift must be non-negative.");
 
         // Try to reuse from previous nodes
         if (_previousNodes != null)
@@ -500,12 +498,16 @@ public void EndUpdate()
         ThrowIfDisposed();
 
         // Dispose unused nodes from previous state
-        if (_previousNodes != null)
+        if (_previousNodes is { Count: > 0 })
         {
             foreach (var prevNode in _previousNodes)
             {
                 if (!_nodes.Contains(prevNode))
                 {
+                    foreach (AudioNode node in _nodes)
+                    {
+                        node.RemoveInput(prevNode);
+                    }
                     prevNode.Dispose();
                 }
             }

src/Beutl.Engine/Audio/Sound.cs

@@ -15,6 +15,8 @@ public Sound()
         ScanProperties<Sound>();
     }
 
+    public IProperty<TimeSpan> OffsetPosition { get; } = Property.Create<TimeSpan>();
+
     [Range(0, float.MaxValue)]
     public IProperty<float> Gain { get; } = Property.CreateAnimatable(100f);
 
@@ -39,8 +41,11 @@ public virtual void Compose(AudioContext context)
         // Create source node
         var sourceNode = context.CreateSourceNode(soundSource);
 
+        var shiftNode = context.CreateShiftNode(OffsetPosition.CurrentValue);
+        context.Connect(sourceNode, shiftNode);
+
         var resampleNode = context.CreateResampleNode(soundSource.SampleRate);
-        context.Connect(sourceNode, resampleNode);
+        context.Connect(shiftNode, resampleNode);
 
         var speedNode = context.CreateSpeedNode(Speed);
         context.Connect(resampleNode, speedNode);

src/Beutl.Engine/Audio/SourceSound.cs

@@ -12,8 +12,6 @@ public SourceSound()
 
     public IProperty<ISoundSource?> Source { get; } = Property.Create<ISoundSource?>();
 
-    public IProperty<TimeSpan> OffsetPosition { get; } = Property.Create<TimeSpan>();
-
     protected override ISoundSource? GetSoundSource()
     {
         return Source.CurrentValue;