fix: use iter_samples() to access per-channel output buffers

Co-authored-by: aider (deepseek/deepseek-coder) <aider@aider.chat>

src/lib.rs

@@ -103,12 +103,29 @@ impl Plugin for ClipLauncher {
 
         // Process audio
         let num_channels = buffer.channels() as usize;
-        let input = buffer.as_slice();
-        let output = buffer.as_mut_slice();
-        let num_frames = input.len() / num_channels;
-        
-        // Process this block
-        self.engine.process_audio(input, output, num_frames);
+        let num_frames = buffer.samples() as usize;
+        let input_slices = buffer.as_slice(); // &[&[f32]]
+
+        // Build interleaved input buffer
+        let mut interleaved_input = vec![0.0; num_frames * num_channels];
+        for ch in 0..num_channels {
+            for frame in 0..num_frames {
+                interleaved_input[frame * num_channels + ch] = input_slices[ch][frame];
+            }
+        }
+
+        // Build interleaved output buffer (will be filled by engine)
+        let mut interleaved_output = vec![0.0; num_frames * num_channels];
+
+        self.engine.process_audio(&interleaved_input, &mut interleaved_output, num_frames);
+
+        // Copy back to buffer's output channels
+        for (ch, channel_samples) in buffer.iter_samples().enumerate() {
+            let output = channel_samples.outputs;
+            for frame in 0..num_frames {
+                output[frame] = interleaved_output[frame * num_channels + ch];
+            }
+        }
 
         // Send pending MIDI output events
         for event in self.pending_midi.drain(..) {