Added audio_data and RecordingAutoStop

src/audio_data.rs

@@ -0,0 +1,465 @@
+use crate::*;
+
+/// Audio data representation supporting sync offsets for column-based timing
+#[derive(Debug)]
+pub enum AudioData {
+    /// No audio data present
+    Empty,
+    
+    /// Unconsolidated linked chunks with sync offset (used during/after recording)
+    Unconsolidated {
+        chunks: Arc<AudioChunk>,
+        sync_offset: usize,  // samples from column start to recording start
+        length: usize,       // total samples in recording
+    },
+    
+    /// Consolidated single buffer, reordered for optimal playback
+    Consolidated {
+        buffer: Box<[f32]>,  // single optimized array
+    },
+}
+
+impl AudioData {
+    /// Create new empty audio data
+    pub fn new_empty() -> Self {
+        Self::Empty
+    }
+    
+    /// Create new unconsolidated audio data from initial chunk
+    pub fn new_unconsolidated<F: ChunkFactory>(
+        chunk_factory: &mut F,
+        sync_offset: usize,
+    ) -> Result<Self> {
+        Ok(Self::Unconsolidated {
+            chunks: chunk_factory.create_chunk()?,
+            sync_offset,
+            length: 0,
+        })
+    }
+    
+    /// Get total length in samples
+    pub fn len(&self) -> usize {
+        match self {
+            Self::Empty => 0,
+            Self::Unconsolidated { length, .. } => *length,
+            Self::Consolidated { buffer } => buffer.len(),
+        }
+    }
+    
+    /// Check if audio data is empty
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+    
+    /// Append samples during recording (only valid for Unconsolidated state)
+    pub fn append_samples<F: ChunkFactory>(
+        &mut self,
+        samples: &[f32],
+        chunk_factory: &mut F,
+    ) -> Result<()> {
+        match self {
+            Self::Unconsolidated { chunks, length, .. } => {
+                chunks.append_samples(samples, chunk_factory)?;
+                *length += samples.len();
+                Ok(())
+            }
+            _ => Err(LooperError::OutOfBounds(std::panic::Location::caller())),
+        }
+    }
+    
+    /// Copy samples to output buffer with volume scaling and looping
+    /// logical_position is the position within the column cycle (0 = beat 1)
+    pub fn copy_samples_to_output(
+        &self,
+        output_slice: &mut [f32],
+        logical_position: usize,
+        volume: f32,
+    ) -> Result<()> {
+        match self {
+            Self::Empty => {
+                output_slice.fill(0.0);
+                Ok(())
+            }
+            Self::Unconsolidated { chunks, sync_offset, length } => {
+                self.copy_unconsolidated_samples(
+                    chunks, 
+                    *sync_offset, 
+                    *length, 
+                    output_slice, 
+                    logical_position, 
+                    volume
+                )
+            }
+            Self::Consolidated { buffer } => {
+                self.copy_consolidated_samples(
+                    buffer, 
+                    output_slice, 
+                    logical_position, 
+                    volume
+                )
+            }
+        }
+    }
+    
+    /// Get underlying chunk for post-record processing
+    pub fn get_chunk_for_processing(&self) -> Option<(Arc<AudioChunk>, usize)> {
+        match self {
+            Self::Unconsolidated { chunks, sync_offset, .. } => {
+                Some((chunks.clone(), *sync_offset))
+            }
+            _ => None,
+        }
+    }
+    
+    /// Replace with consolidated buffer from post-record processing
+    pub fn set_consolidated_buffer(&mut self, buffer: Box<[f32]>) -> Result<()> {
+        match self {
+            Self::Unconsolidated { length: old_length, .. } => {
+                if buffer.len() != *old_length {
+                    return Err(LooperError::OutOfBounds(std::panic::Location::caller()));
+                }
+                *self = Self::Consolidated { buffer };
+                Ok(())
+            }
+            _ => Err(LooperError::OutOfBounds(std::panic::Location::caller())),
+        }
+    }
+    
+    /// Clear all audio data
+    pub fn clear(&mut self) -> Result<()> {
+        *self = Self::Empty;
+        Ok(())
+    }
+}
+
+impl AudioData {
+    /// Copy samples from unconsolidated chunks with sync offset handling
+    fn copy_unconsolidated_samples(
+        &self,
+        chunks: &Arc<AudioChunk>,
+        sync_offset: usize,
+        length: usize,
+        output_slice: &mut [f32],
+        mut logical_position: usize,
+        volume: f32,
+    ) -> Result<()> {
+        if length == 0 {
+            output_slice.fill(0.0);
+            return Ok(());
+        }
+        
+        let mut samples_written = 0;
+        let samples_needed = output_slice.len();
+        
+        while samples_written < samples_needed {
+            let samples_remaining = samples_needed - samples_written;
+            let samples_until_loop = length - logical_position;
+            let samples_to_copy = samples_remaining.min(samples_until_loop);
+            
+            // Map logical position to buffer position using sync offset
+            let buffer_position = (logical_position + sync_offset) % length;
+            
+            // Copy from chunks to output slice
+            chunks.copy_samples(
+                &mut output_slice[samples_written..samples_written + samples_to_copy],
+                buffer_position,
+            )?;
+            
+            // Apply volume scaling in-place
+            for sample in &mut output_slice[samples_written..samples_written + samples_to_copy] {
+                *sample *= volume;
+            }
+            
+            samples_written += samples_to_copy;
+            logical_position += samples_to_copy;
+            
+            // Handle looping
+            if logical_position >= length {
+                logical_position = 0;
+            }
+        }
+        
+        Ok(())
+    }
+    
+    /// Copy samples from consolidated buffer (already reordered)
+    fn copy_consolidated_samples(
+        &self,
+        buffer: &[f32],
+        output_slice: &mut [f32],
+        mut logical_position: usize,
+        volume: f32,
+    ) -> Result<()> {
+        let length = buffer.len();
+        if length == 0 {
+            output_slice.fill(0.0);
+            return Ok(());
+        }
+        
+        let mut samples_written = 0;
+        let samples_needed = output_slice.len();
+        
+        while samples_written < samples_needed {
+            let samples_remaining = samples_needed - samples_written;
+            let samples_until_loop = length - logical_position;
+            let samples_to_copy = samples_remaining.min(samples_until_loop);
+            
+            // Direct copy since consolidated buffer is already reordered
+            let src = &buffer[logical_position..logical_position + samples_to_copy];
+            let dest = &mut output_slice[samples_written..samples_written + samples_to_copy];
+            dest.copy_from_slice(src);
+            
+            // Apply volume scaling in-place
+            for sample in dest {
+                *sample *= volume;
+            }
+            
+            samples_written += samples_to_copy;
+            logical_position += samples_to_copy;
+            
+            // Handle looping
+            if logical_position >= length {
+                logical_position = 0;
+            }
+        }
+        
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::chunk_factory::mock::MockFactory;
+
+    #[test]
+    fn test_new_empty() {
+        let audio_data = AudioData::new_empty();
+        
+        assert_eq!(audio_data.len(), 0);
+        assert!(audio_data.is_empty());
+    }
+    
+    #[test] 
+    fn test_new_unconsolidated() {
+        let mut factory = MockFactory::new(vec![AudioChunk::allocate(1024)]);
+        let sync_offset = 100;
+        
+        let audio_data = AudioData::new_unconsolidated(&mut factory, sync_offset).unwrap();
+        
+        match audio_data {
+            AudioData::Unconsolidated { sync_offset: offset, length, .. } => {
+                assert_eq!(offset, 100);
+                assert_eq!(length, 0);
+            }
+            _ => panic!("Expected Unconsolidated variant"),
+        }
+    }
+    
+    #[test]
+    fn test_append_samples_unconsolidated() {
+        let mut factory = MockFactory::new(vec![AudioChunk::allocate(1024)]);
+        let mut audio_data = AudioData::new_unconsolidated(&mut factory, 0).unwrap();
+        
+        let samples = vec![1.0, 2.0, 3.0, 4.0];
+        audio_data.append_samples(&samples, &mut factory).unwrap();
+        
+        assert_eq!(audio_data.len(), 4);
+        assert!(!audio_data.is_empty());
+    }
+    
+    #[test]
+    fn test_append_samples_invalid_state() {
+        let mut factory = MockFactory::new(vec![]);
+        let mut audio_data = AudioData::new_empty();
+        
+        let samples = vec![1.0, 2.0];
+        let result = audio_data.append_samples(&samples, &mut factory);
+        
+        assert!(result.is_err());
+    }
+    
+    #[test]
+    fn test_copy_samples_empty() {
+        let audio_data = AudioData::new_empty();
+        let mut output = vec![99.0; 4]; // Fill with non-zero to verify silence
+        
+        audio_data.copy_samples_to_output(&mut output, 0, 1.0).unwrap();
+        
+        assert_eq!(output, vec![0.0, 0.0, 0.0, 0.0]);
+    }
+    
+    #[test]
+    fn test_copy_samples_unconsolidated_no_offset() {
+        let mut factory = MockFactory::new(vec![AudioChunk::allocate(10)]);
+        let mut audio_data = AudioData::new_unconsolidated(&mut factory, 0).unwrap();
+        
+        // Add some test samples
+        let samples = vec![1.0, 2.0, 3.0, 4.0];
+        audio_data.append_samples(&samples, &mut factory).unwrap();
+        
+        let mut output = vec![0.0; 4];
+        audio_data.copy_samples_to_output(&mut output, 0, 1.0).unwrap();
+        
+        assert_eq!(output, vec![1.0, 2.0, 3.0, 4.0]);
+    }
+    
+    #[test]
+    fn test_copy_samples_unconsolidated_with_offset() {
+        let mut factory = MockFactory::new(vec![AudioChunk::allocate(10)]);
+        let sync_offset = 2;
+        let mut audio_data = AudioData::new_unconsolidated(&mut factory, sync_offset).unwrap();
+        
+        // Recording order: [A, B, C, D] but recorded starting at beat 3 (sync_offset=2)
+        // So logical mapping should be: beat1=C, beat2=D, beat3=A, beat4=B
+        let samples = vec![10.0, 20.0, 30.0, 40.0]; // A, B, C, D
+        audio_data.append_samples(&samples, &mut factory).unwrap();
+        
+        let mut output = vec![0.0; 4];
+        audio_data.copy_samples_to_output(&mut output, 0, 1.0).unwrap(); // Start at logical beat 1
+        
+        // Should get: [C, D, A, B] = [30.0, 40.0, 10.0, 20.0]
+        assert_eq!(output, vec![30.0, 40.0, 10.0, 20.0]);
+    }
+    
+    #[test]
+    fn test_copy_samples_unconsolidated_with_volume() {
+        let mut factory = MockFactory::new(vec![AudioChunk::allocate(10)]);
+        let mut audio_data = AudioData::new_unconsolidated(&mut factory, 0).unwrap();
+        
+        let samples = vec![1.0, 2.0, 3.0, 4.0];
+        audio_data.append_samples(&samples, &mut factory).unwrap();
+        
+        let mut output = vec![0.0; 4];
+        audio_data.copy_samples_to_output(&mut output, 0, 0.5).unwrap(); // 50% volume
+        
+        assert_eq!(output, vec![0.5, 1.0, 1.5, 2.0]);
+    }
+    
+    #[test]
+    fn test_copy_samples_unconsolidated_looping() {
+        let mut factory = MockFactory::new(vec![AudioChunk::allocate(10)]);
+        let mut audio_data = AudioData::new_unconsolidated(&mut factory, 0).unwrap();
+        
+        let samples = vec![1.0, 2.0];
+        audio_data.append_samples(&samples, &mut factory).unwrap();
+        
+        let mut output = vec![0.0; 6]; // Request more samples than available
+        audio_data.copy_samples_to_output(&mut output, 0, 1.0).unwrap();
+        
+        // Should loop: [1.0, 2.0, 1.0, 2.0, 1.0, 2.0]
+        assert_eq!(output, vec![1.0, 2.0, 1.0, 2.0, 1.0, 2.0]);
+    }
+    
+    #[test]
+    fn test_copy_samples_unconsolidated_offset_with_looping() {
+        let mut factory = MockFactory::new(vec![AudioChunk::allocate(10)]);
+        let sync_offset = 1;
+        let mut audio_data = AudioData::new_unconsolidated(&mut factory, sync_offset).unwrap();
+        
+        // Recording: [A, B, C] starting at beat 2 (sync_offset=1)
+        // Logical mapping: beat1=B, beat2=C, beat3=A
+        let samples = vec![10.0, 20.0, 30.0]; 
+        audio_data.append_samples(&samples, &mut factory).unwrap();
+        
+        let mut output = vec![0.0; 6]; // Request 2 full loops
+        audio_data.copy_samples_to_output(&mut output, 0, 1.0).unwrap();
+        
+        // Should get: [B, C, A, B, C, A] = [20.0, 30.0, 10.0, 20.0, 30.0, 10.0]
+        assert_eq!(output, vec![20.0, 30.0, 10.0, 20.0, 30.0, 10.0]);
+    }
+    
+    #[test]
+    fn test_copy_samples_consolidated() {
+        // Create consolidated data directly
+        let buffer = vec![1.0, 2.0, 3.0, 4.0].into_boxed_slice();
+        
+        let audio_data = AudioData::Consolidated { buffer };
+        
+        let mut output = vec![0.0; 4];
+        audio_data.copy_samples_to_output(&mut output, 0, 1.0).unwrap();
+        
+        assert_eq!(output, vec![1.0, 2.0, 3.0, 4.0]);
+    }
+    
+    #[test]
+    fn test_get_chunk_for_processing() {
+        let mut factory = MockFactory::new(vec![AudioChunk::allocate(10)]);
+        let sync_offset = 42;
+        let mut audio_data = AudioData::new_unconsolidated(&mut factory, sync_offset).unwrap();
+        
+        let samples = vec![1.0, 2.0, 3.0];
+        audio_data.append_samples(&samples, &mut factory).unwrap();
+        
+        let result = audio_data.get_chunk_for_processing();
+        assert!(result.is_some());
+        
+        let (chunk, offset) = result.unwrap();
+        assert_eq!(offset, 42);
+        assert_eq!(chunk.len(), 3);
+    }
+    
+    #[test]
+    fn test_get_chunk_for_processing_wrong_state() {
+        let audio_data = AudioData::new_empty();
+        let result = audio_data.get_chunk_for_processing();
+        assert!(result.is_none());
+    }
+    
+    #[test]
+    fn test_set_consolidated_buffer() {
+        let mut factory = MockFactory::new(vec![AudioChunk::allocate(10)]);
+        let mut audio_data = AudioData::new_unconsolidated(&mut factory, 100).unwrap();
+        
+        let samples = vec![1.0, 2.0, 3.0, 4.0];
+        audio_data.append_samples(&samples, &mut factory).unwrap();
+        
+        // Create consolidated buffer with same length
+        let consolidated_buffer = vec![10.0, 20.0, 30.0, 40.0].into_boxed_slice();
+        
+        audio_data.set_consolidated_buffer(consolidated_buffer).unwrap();
+        
+        // Should now be Consolidated variant
+        match audio_data {
+            AudioData::Consolidated { buffer } => {
+                assert_eq!(buffer.len(), 4);
+            }
+            _ => panic!("Expected Consolidated variant"),
+        }
+    }
+    
+    #[test]
+    fn test_set_consolidated_buffer_length_mismatch() {
+        let mut factory = MockFactory::new(vec![AudioChunk::allocate(10)]);
+        let mut audio_data = AudioData::new_unconsolidated(&mut factory, 0).unwrap();
+        
+        let samples = vec![1.0, 2.0]; // Length 2
+        audio_data.append_samples(&samples, &mut factory).unwrap();
+        
+        // Try to set buffer with different length
+        let wrong_length_buffer = vec![10.0, 20.0, 30.0, 40.0].into_boxed_slice(); // Length 4
+        
+        let result = audio_data.set_consolidated_buffer(wrong_length_buffer);
+        assert!(result.is_err());
+    }
+    
+    #[test]
+    fn test_clear() {
+        let mut factory = MockFactory::new(vec![AudioChunk::allocate(10)]);
+        let mut audio_data = AudioData::new_unconsolidated(&mut factory, 0).unwrap();
+        
+        let samples = vec![1.0, 2.0, 3.0];
+        audio_data.append_samples(&samples, &mut factory).unwrap();
+        assert_eq!(audio_data.len(), 3);
+        
+        audio_data.clear().unwrap();
+        
+        assert_eq!(audio_data.len(), 0);
+        assert!(audio_data.is_empty());
+        
+        match audio_data {
+            AudioData::Empty => (), // Expected
+            _ => panic!("Expected Empty variant after clear"),
+        }
+    }
+}

src/audio_engine.rs

@@ -1,5 +1,6 @@
 mod allocator;
 mod audio_chunk;
+mod audio_data;
 mod chunk_factory;
 mod connection_manager;
 mod looper_error;
@@ -16,6 +17,7 @@ use std::sync::Arc;
 
 use allocator::Allocator;
 use audio_chunk::AudioChunk;
+use audio_data::AudioData;
 use chunk_factory::ChunkFactory;
 use connection_manager::ConnectionManager;
 use looper_error::LooperError;

src/metronome.rs

@@ -21,6 +21,10 @@ impl Metronome {
         }
     }
 
+    pub fn samples_per_beat(&self) -> u32 {
+        self.samples_per_beat
+    }
+
     /// Process audio for current buffer, writing to output slice
     /// Returns the sample index where a beat occurred, if any
     pub fn process(&mut self, ps: &jack::ProcessScope, ports: &mut JackPorts) -> Result<Option<u32>> {

src/midi.rs

@@ -45,6 +45,10 @@ pub fn process_events<F: ChunkFactory>(
                                     // Button 2: Play/Mute
                                     process_handler.play_toggle()?;
                                 }
+                                22 => {
+                                    // Button 3: Auto-stop record
+                                    process_handler.record_auto_stop()?;
+                                }
                                 24 => {
                                     // Button 5: Clear track
                                     process_handler.clear_track()?;

src/post_record_handler.rs

@@ -1,17 +1,18 @@
 use crate::*;
 use std::path::PathBuf;
 
-/// Request to process a recorded chunk chain
+/// Request to process a recorded chunk chain with sync offset
 #[derive(Debug)]
 pub struct PostRecordRequest {
     pub chunk_chain: Arc<AudioChunk>,
+    pub sync_offset: u32,
     pub sample_rate: u32,
 }
 
-/// Response containing the consolidated chunk
+/// Response containing the consolidated buffer
 #[derive(Debug)]
 pub struct PostRecordResponse {
-    pub consolidated_chunk: Arc<AudioChunk>,
+    pub consolidated_buffer: Box<[f32]>,
 }
 
 /// RT-side interface for post-record operations
@@ -23,8 +24,8 @@ pub struct PostRecordController {
 
 impl PostRecordController {
     /// Send a post-record processing request (RT-safe)
-    pub fn send_request(&self, chunk_chain: Arc<AudioChunk>, sample_rate: u32) -> Result<()> {
-        let request = PostRecordRequest { chunk_chain, sample_rate };
+    pub fn send_request(&self, chunk_chain: Arc<AudioChunk>, sync_offset: u32, sample_rate: u32) -> Result<()> {
+        let request = PostRecordRequest { chunk_chain, sync_offset, sample_rate };
         
         match self.request_sender.try_send(request) {
             Ok(true) => Ok(()),  // Successfully sent
@@ -42,7 +43,7 @@ impl PostRecordController {
     }
 }
 
-/// Handles post-record processing: consolidation and saving
+/// Handles post-record processing: consolidation with sync offset and saving
 pub struct PostRecordHandler {
     request_receiver: kanal::AsyncReceiver<PostRecordRequest>,
     response_sender: kanal::AsyncSender<PostRecordResponse>,
@@ -89,24 +90,27 @@ impl PostRecordHandler {
         &self,
         request: PostRecordRequest,
     ) -> Result<()> {
-        log::debug!("Processing post-record request for {} samples", 
-                   request.chunk_chain.len());
+        log::debug!("Processing post-record request for {} samples with sync_offset {}", 
+                   request.chunk_chain.len(), request.sync_offset);
 
-        // Step 1: Consolidate chunk chain (CPU intensive)
-        let consolidated_chunk = AudioChunk::consolidate(&request.chunk_chain);
+        // Step 1: Consolidate and reorder chunk chain based on sync offset
+        let consolidated_buffer = self.consolidate_with_sync_offset(
+            &request.chunk_chain, 
+            request.sync_offset as usize
+        )?;
         
-        log::debug!("Consolidated {} samples", consolidated_chunk.sample_count);
+        log::debug!("Consolidated and reordered {} samples", consolidated_buffer.len());
 
-        // Step 2: Send consolidated chunk back to RT thread immediately
-        let response = PostRecordResponse {
-            consolidated_chunk: consolidated_chunk.clone(),
-        };
+        // Step 2: Send consolidated buffer back to RT thread immediately
+        let response = PostRecordResponse { consolidated_buffer };
         
         if let Err(_) = self.response_sender.send(response).await {
-            log::warn!("Failed to send consolidated chunk to RT thread");
+            log::warn!("Failed to send consolidated buffer to RT thread");
         }
 
         // Step 3: Save WAV file in background (I/O intensive)
+        // Use original chunk chain for saving (not reordered)
+        let consolidated_chunk = AudioChunk::consolidate(&request.chunk_chain);
         let file_path = self.get_file_path();
 
         match self.save_wav_file(&consolidated_chunk, request.sample_rate, &file_path).await {
@@ -117,6 +121,36 @@ impl PostRecordHandler {
         Ok(())
     }
 
+    /// Consolidate chunk chain and reorder samples based on sync offset
+    fn consolidate_with_sync_offset(&self, chunk_chain: &Arc<AudioChunk>, sync_offset: usize) -> Result<Box<[f32]>> {
+        let total_length = chunk_chain.len();
+        
+        if total_length == 0 {
+            return Ok(Vec::new().into_boxed_slice());
+        }
+
+        // Step 1: Extract all samples from the chunk chain into a temporary buffer
+        let mut all_samples = vec![0.0; total_length];
+        chunk_chain.copy_samples(&mut all_samples, 0)?;
+
+        // Step 2: Reorder samples based on sync offset
+        // The goal is to put the sample that represents "logical beat 1" at index 0
+        if sync_offset == 0 {
+            // No offset - return samples as-is
+            return Ok(all_samples.into_boxed_slice());
+        }
+
+        let mut reordered = Vec::with_capacity(total_length);
+        
+        // For each output position, calculate which input position to take from
+        for i in 0..total_length {
+            let source_index = (i + sync_offset) % total_length;
+            reordered.push(all_samples[source_index]);
+        }
+
+        Ok(reordered.into_boxed_slice())
+    }
+
     /// Save consolidated chunk as WAV file
     async fn save_wav_file(
         &self,

src/process_handler.rs

@@ -1,5 +1,9 @@
 use crate::*;
 
+// Testing constants for sync offset functionality
+const SYNC_OFFSET_BEATS: u32 = 2;  // Start recording at beat 3 (0-indexed)
+const AUTO_STOP_BEATS: u32 = 4;    // Record for 4 beats total
+
 pub struct ProcessHandler<F: ChunkFactory> {
     track: Track,
     playback_position: usize,
@@ -12,13 +16,13 @@ pub struct ProcessHandler<F: ChunkFactory> {
 impl<F: ChunkFactory> ProcessHandler<F> {
     pub fn new(
         ports: JackPorts, 
-        mut chunk_factory: F, 
+        chunk_factory: F, 
         beep_samples: Arc<AudioChunk>, 
         state: &State,
         post_record_controller: PostRecordController,
     ) -> Result<Self> {
         Ok(Self {
-            track: Track::new(&mut chunk_factory)?,
+            track: Track::new(),
             playback_position: 0,
             ports,
             chunk_factory,
@@ -39,6 +43,16 @@ impl<F: ChunkFactory> ProcessHandler<F> {
         Ok(())
     }
 
+    /// Handle auto-stop record button (Button 3) 
+    pub fn record_auto_stop(&mut self) -> Result<()> {
+        let samples_per_beat = self.metronome.samples_per_beat();
+        let sync_offset = SYNC_OFFSET_BEATS * samples_per_beat;
+        let target_samples = AUTO_STOP_BEATS * samples_per_beat;
+        
+        self.track.queue_record_auto_stop(target_samples as usize, sync_offset as usize);
+        Ok(())
+    }
+
     /// Handle clear button (Button 5)
     pub fn clear_track(&mut self) -> Result<()> {
         self.track.queue_clear();
@@ -97,26 +111,18 @@ impl<F: ChunkFactory> jack::ProcessHandler for ProcessHandler<F> {
 }
 
 impl<F: ChunkFactory> ProcessHandler<F> {
-    /// Handle post-record processing: send requests and swap chunks
+    /// Handle post-record processing: send requests and swap buffers
     fn handle_post_record_processing(&mut self, should_consolidate: bool, sample_rate: u32) -> Result<()> {
-        // Send chunk chain for processing if track indicates consolidation needed
+        // Send audio data for processing if track indicates consolidation needed
         if should_consolidate {
-            let chunk_chain = self.track.get_audio_chunk();
-            log::debug!("Sending chunk chain with {} samples for post-record processing", 
-                        chunk_chain.len());
-            
-            if let Err(e) = self.post_record_controller.send_request(chunk_chain, sample_rate) {
-                log::warn!("Failed to send post-record request: {}", e);
+            if let Some((chunk_chain, sync_offset)) = self.track.get_audio_data_for_processing() {
+                self.post_record_controller.send_request(chunk_chain, sync_offset as u32, sample_rate)?;
             }
         }
 
         // Check for consolidation response
         if let Some(response) = self.post_record_controller.try_recv_response() {
-            log::debug!("Received consolidated chunk with {} samples, swapping in track", 
-                       response.consolidated_chunk.len());
-            
-            // Swap the consolidated chunk into the track
-            self.track.set_audio_chunk(response.consolidated_chunk)?;
+            self.track.set_consolidated_buffer(response.consolidated_buffer)?;
         }
 
         Ok(())
@@ -154,7 +160,7 @@ impl<F: ChunkFactory> ProcessHandler<F> {
         let state_after = self.track.next_state(); // Use next_state since transition hasn't happened yet
         
         match (state_before, state_after) {
-            (_, TrackState::Playing) if *state_before != TrackState::Playing => {
+            (_, TrackState::Playing) if !matches!(state_before, TrackState::Playing) => {
                 // Just started playing - start from beginning
                 // Note: In future Column implementation, this will be:
                 // column.get_sync_position() to sync with other playing tracks
@@ -197,7 +203,7 @@ impl<F: ChunkFactory> ProcessHandler<F> {
                 }
                 
                 // Check if state transition at beat affects position
-                if state_after == TrackState::Playing && *state_before != TrackState::Playing {
+                if state_after == TrackState::Playing && !matches!(state_before, TrackState::Playing) {
                     // Started playing at beat - reset position to post-beat calculation
                     self.playback_position = self.calculate_post_beat_position(state_before);
                 }

src/track.rs

@@ -5,7 +5,11 @@ pub enum TrackState {
     Empty,     // No audio data (---)
     Idle,      // Has data, not playing (READY)
     Playing,   // Currently playing (PLAY)
-    Recording, // Currently recording (REC)
+    Recording, // Currently recording (REC) - manual stop
+    RecordingAutoStop { 
+        target_samples: usize,  // Auto-stop when this many samples recorded
+        sync_offset: usize,     // Offset in samples from column start
+    },
 }
 
 #[derive(Debug)]
@@ -21,22 +25,20 @@ pub enum TrackTiming {
 }
 
 pub struct Track {
-    audio_chunk: Arc<AudioChunk>,
-    length: usize,
+    audio_data: AudioData,
     current_state: TrackState,
     next_state: TrackState,
     volume: f32,
 }
 
 impl Track {
-    pub fn new<F: ChunkFactory>(chunk_factory: &mut F) -> Result<Self> {
-        Ok(Self {
-            audio_chunk: chunk_factory.create_chunk()?,
-            length: 0,
+    pub fn new() -> Self {
+        Self {
+            audio_data: AudioData::new_empty(),
             current_state: TrackState::Empty,
             next_state: TrackState::Empty,
             volume: 1.0,
-        })
+        }
     }
 
     /// Main audio processing method called from ProcessHandler
@@ -119,25 +121,51 @@ impl Track {
             return Ok(());
         }
 
-        match self.current_state {
+        match &mut self.current_state {
             TrackState::Empty | TrackState::Idle => {
                 // Output silence for this range
                 output_buffer[start_index..end_index].fill(0.0);
             }
             TrackState::Recording => {
-                // Record input samples
+                // Record input samples (manual recording)
                 let samples_to_record = &input_buffer[start_index..end_index];
-                self.append_samples(samples_to_record, chunk_factory)?;
+                self.audio_data.append_samples(samples_to_record, chunk_factory)?;
+                
+                // Output silence during recording
+                output_buffer[start_index..end_index].fill(0.0);
+            }
+            TrackState::RecordingAutoStop { target_samples, .. } => {
+                // Record input samples with auto-stop logic
+                let samples_to_record = &input_buffer[start_index..end_index];
+                let current_length = self.audio_data.len();
+                
+                if current_length < *target_samples {
+                    // Still recording - determine how many samples to actually record
+                    let samples_needed = *target_samples - current_length;
+                    let samples_to_append = samples_to_record.len().min(samples_needed);
+                    
+                    if samples_to_append > 0 {
+                        self.audio_data.append_samples(
+                            &samples_to_record[..samples_to_append], 
+                            chunk_factory
+                        )?;
+                    }
+                    
+                    // Check if we've reached target and should auto-transition
+                    if self.audio_data.len() >= *target_samples {
+                        self.next_state = TrackState::Playing;
+                    }
+                }
                 
                 // Output silence during recording
                 output_buffer[start_index..end_index].fill(0.0);
             }
             TrackState::Playing => {
                 // Playback with looping
-                self.copy_samples_to_output(
+                self.audio_data.copy_samples_to_output(
                     &mut output_buffer[start_index..end_index],
-                    sample_count,
                     playback_position,
+                    self.volume,
                 )?;
             }
         }
@@ -151,28 +179,34 @@ impl Track {
         &mut self, 
         chunk_factory: &mut F
     ) -> Result<bool> {
-        // Check if this is a Recording → Playing transition (consolidation trigger)
-        let should_consolidate = self.current_state == TrackState::Recording 
-                                 && self.next_state == TrackState::Playing;
+        // Check if this is a recording → playing transition (consolidation trigger)
+        let should_consolidate = matches!(
+            (&self.current_state, &self.next_state),
+            (TrackState::Recording, TrackState::Playing) |
+            (TrackState::RecordingAutoStop { .. }, TrackState::Playing)
+        );
 
         // Handle transitions that require setup
         match (&self.current_state, &self.next_state) {
-            (current_state, TrackState::Recording) if *current_state != TrackState::Recording => {
-                // Starting to record - clear previous data and create new chunk
-                self.clear_audio_data(chunk_factory)?;
+            (current_state, TrackState::Recording) if !matches!(current_state, TrackState::Recording) => {
+                // Starting manual recording - clear previous data and create new unconsolidated data
+                self.audio_data = AudioData::new_unconsolidated(chunk_factory, 0)?;
+            }
+            (current_state, TrackState::RecordingAutoStop { sync_offset, .. }) 
+                if !matches!(current_state, TrackState::RecordingAutoStop { .. }) => {
+                // Starting auto-stop recording - clear previous data and create new unconsolidated data with offset
+                self.audio_data = AudioData::new_unconsolidated(chunk_factory, *sync_offset)?;
             }
             (_, TrackState::Playing) => {
                 // Starting playback - check if we have audio data
-                if self.length == 0 {
+                if self.audio_data.is_empty() {
                     // No audio data - transition to Idle instead
                     self.next_state = TrackState::Idle;
                 }
             }
             (_, TrackState::Empty) => {
                 // Clear operation - remove audio data
-                // Note: Actual deallocation will happen later via IO thread
-                self.audio_chunk = chunk_factory.create_chunk()?;
-                self.length = 0;
+                self.audio_data.clear()?;
             }
             _ => {
                 // Other transitions don't require special handling
@@ -185,80 +219,14 @@ impl Track {
         Ok(should_consolidate)
     }
 
-    /// Copy samples from track audio to output buffer with looping
-    fn copy_samples_to_output(
-        &self,
-        output_slice: &mut [f32],
-        sample_count: usize,
-        mut playback_position: usize,
-    ) -> Result<()> {
-        if self.length == 0 {
-            output_slice.fill(0.0);
-            return Ok(());
-        }
-
-        let mut samples_written = 0;
-
-        while samples_written < sample_count {
-            let samples_remaining = sample_count - samples_written;
-            let samples_until_loop = self.length - playback_position;
-            let samples_to_copy = samples_remaining.min(samples_until_loop);
-
-            // Copy directly from audio chunk to output slice
-            self.audio_chunk.copy_samples(
-                &mut output_slice[samples_written..samples_written + samples_to_copy],
-                playback_position,
-            )?;
-
-            // Apply volume scaling in-place
-            for sample in &mut output_slice[samples_written..samples_written + samples_to_copy] {
-                *sample *= self.volume;
-            }
-
-            samples_written += samples_to_copy;
-            playback_position += samples_to_copy;
-
-            // Handle looping
-            if playback_position >= self.length {
-                playback_position = 0;
-            }
-        }
-        Ok(())
+    /// Get audio data for post-record processing (returns chunk and sync offset)
+    pub fn get_audio_data_for_processing(&self) -> Option<(Arc<AudioChunk>, usize)> {
+        self.audio_data.get_chunk_for_processing()
     }
 
-    /// Append samples to the track's audio data
-    pub fn append_samples<F: ChunkFactory>(
-        &mut self,
-        samples: &[f32],
-        chunk_factory: &mut F,
-    ) -> Result<()> {
-        self.audio_chunk.append_samples(samples, chunk_factory)?;
-        self.length += samples.len();
-        Ok(())
-    }
-
-    /// Clear all audio data from the track
-    fn clear_audio_data<F: ChunkFactory>(
-        &mut self,
-        chunk_factory: &mut F,
-    ) -> Result<()> {
-        self.audio_chunk = chunk_factory.create_chunk()?;
-        self.length = 0;
-        Ok(())
-    }
-
-    /// Get audio chunk for post-record processing (read-only access)
-    pub fn get_audio_chunk(&self) -> Arc<AudioChunk> {
-        self.audio_chunk.clone()
-    }
-
-    /// Set audio chunk (for swapping in consolidated chunk)
-    pub fn set_audio_chunk(&mut self, chunk: Arc<AudioChunk>) -> Result<()> {
-        if chunk.len() != self.length {
-            return Err(LooperError::OutOfBounds(std::panic::Location::caller()));
-        }
-        self.audio_chunk = chunk;
-        Ok(())
+    /// Set consolidated buffer (for swapping in consolidated audio data)
+    pub fn set_consolidated_buffer(&mut self, buffer: Box<[f32]>) -> Result<()> {
+        self.audio_data.set_consolidated_buffer(buffer)
     }
 
     // Public accessors and commands for MIDI handling
@@ -271,7 +239,7 @@ impl Track {
     }
 
     pub fn len(&self) -> usize {
-        self.length
+        self.audio_data.len()
     }
 
     pub fn volume(&self) -> f32 {
@@ -291,12 +259,37 @@ impl Track {
             TrackState::Recording => {
                 self.next_state = TrackState::Playing;
             }
+            TrackState::RecordingAutoStop { .. } => {
+                // Auto-stop recording - can't manually stop, wait for auto-transition
+                self.next_state = self.current_state.clone();
+            }
             TrackState::Playing => {
                 self.next_state = TrackState::Idle;
             }
         }
     }
 
+    /// Handle auto-stop record command (sets next_state)
+    pub fn queue_record_auto_stop(&mut self, target_samples: usize, sync_offset: usize) {
+        match self.current_state {
+            TrackState::Empty | TrackState::Idle => {
+                self.next_state = TrackState::RecordingAutoStop { target_samples, sync_offset };
+            }
+            TrackState::Recording => {
+                // Switch from manual to auto-stop recording
+                self.next_state = TrackState::RecordingAutoStop { target_samples, sync_offset };
+            }
+            TrackState::RecordingAutoStop { .. } => {
+                // Already auto-recording - update parameters
+                self.next_state = TrackState::RecordingAutoStop { target_samples, sync_offset };
+            }
+            TrackState::Playing => {
+                // Stop playing and start auto-recording
+                self.next_state = TrackState::RecordingAutoStop { target_samples, sync_offset };
+            }
+        }
+    }
+
     /// Handle play/mute toggle command (sets next_state)
     pub fn queue_play_toggle(&mut self) {
         match self.current_state {
@@ -305,15 +298,15 @@ impl Track {
                 self.next_state = TrackState::Empty;
             }
             TrackState::Idle => {
-                if self.length > 0 {
+                if !self.audio_data.is_empty() {
                     self.next_state = TrackState::Playing;
                 } else {
                     self.next_state = TrackState::Idle;
                 }
             }
-            TrackState::Recording => {
+            TrackState::Recording | TrackState::RecordingAutoStop { .. } => {
                 // Don't change state while recording
-                self.next_state = TrackState::Recording;
+                self.next_state = self.current_state.clone();
             }
             TrackState::Playing => {
                 self.next_state = TrackState::Idle;