Separated CameraController from the main loop

CameraController.cs

@@ -0,0 +1,155 @@
+using System;
+using OpenCvSharp;
+
+namespace splitter;
+
+public enum TrackState
+{
+    Tracking,
+    LostFreeze,
+    LostDrift
+}
+
+public sealed class CameraController
+{
+    private readonly int _videoWidth;
+    private readonly int _videoHeight;
+    private readonly int _cropWidth;
+    private readonly int _cropHeight;
+    private readonly KalmanTracker _kalman;
+    private readonly int _lostFreezeFrames;
+    private readonly float _cameraEasing;
+
+    private int _lostFrames;
+    private Point2f _cameraCenter;
+    private TrackState _state;
+    private Point2f _smoothedCenter;
+    private Rect? _objectBox;
+    private Point2f? _objectCenter;
+    private Rect _roi;
+
+    public CameraController(
+        int videoWidth,
+        int videoHeight,
+        int cropWidth,
+        int cropHeight,
+        KalmanTracker kalman,
+        int lostFreezeFrames,
+        float cameraEasing)
+    {
+        _videoWidth = videoWidth;
+        _videoHeight = videoHeight;
+        _cropWidth = cropWidth;
+        _cropHeight = cropHeight;
+        _kalman = kalman;
+        _lostFreezeFrames = lostFreezeFrames;
+        _cameraEasing = cameraEasing;
+
+        _cameraCenter = new Point2f(videoWidth / 2f, videoHeight / 2f);
+        _state = TrackState.Tracking;
+
+        _kalman.Reset(_cameraCenter);
+    }
+
+    public int LostFrames => _lostFrames;
+    public Point2f CameraCenter => _cameraCenter;
+    public TrackState State => _state;
+    public Point2f SmoothedCenter => _smoothedCenter;
+    public Rect? ObjectBox => _objectBox;
+    public Point2f? ObjectCenter => _objectCenter;
+    public Rect Roi => _roi;
+
+    public void Update((Rect box, Point2f center)? primary)
+    {
+        Rect?    objectBox    = null;
+        Point2f? objectCenter = null;
+
+        if (primary.HasValue)
+        {
+            objectCenter = primary.Value.center;
+            objectBox = primary.Value.box;
+        }
+
+        bool isLost = !objectCenter.HasValue;
+
+        // LOST / REACQUIRE STATE MACHINE
+        if (isLost)
+        {
+            _lostFrames++;
+
+            if (_lostFrames <= _lostFreezeFrames)
+            {
+                // LOST_FREEZE: freeze camera
+                _state = TrackState.LostFreeze;
+                objectCenter = null; // Kalman predicts but camera won't move
+            }
+            else
+            {
+                // LOST_DRIFT: drift camera to center
+                _state = TrackState.LostDrift;
+                objectCenter = new Point2f(_videoWidth / 2f, _videoHeight / 2f);
+            }
+        }
+        else
+        {
+            // Object reacquired
+            _state = TrackState.Tracking;
+            _lostFrames = 0;
+        }
+
+        // KALMAN + CAMERA UPDATE
+        Point2f smoothedCenter;
+
+        if (_state == TrackState.Tracking)
+        {
+            smoothedCenter = _kalman.Update(objectCenter);
+
+            // first, faster internal easing (as in your original code)
+            float fastEasing = 0.015f;
+            _cameraCenter = new Point2f(
+                _cameraCenter.X + (smoothedCenter.X - _cameraCenter.X) * fastEasing,
+                _cameraCenter.Y + (smoothedCenter.Y - _cameraCenter.Y) * fastEasing);
+
+            // then, external configurable easing
+            _cameraCenter = new Point2f(
+                _cameraCenter.X + (smoothedCenter.X - _cameraCenter.X) * _cameraEasing,
+                _cameraCenter.Y + (smoothedCenter.Y - _cameraCenter.Y) * _cameraEasing);
+        }
+        else if (_state == TrackState.LostFreeze)
+        {
+            // Freeze camera — do nothing
+            smoothedCenter = _kalman.LastMeasurement ?? _cameraCenter;
+        }
+        else // LOST_DRIFT
+        {
+            smoothedCenter = _kalman.Update(objectCenter);
+
+            float driftEasing = 0.01f;
+            var fallbackCenter = new Point2f(_videoWidth / 2f, _videoHeight / 2f);
+
+            _cameraCenter = new Point2f(
+                _cameraCenter.X + (fallbackCenter.X - _cameraCenter.X) * driftEasing,
+                _cameraCenter.Y + (fallbackCenter.Y - _cameraCenter.Y) * driftEasing);
+        }
+
+        var halfW = _cropWidth  / 2f;
+        var halfH = _cropHeight / 2f;
+
+        smoothedCenter.X = Math.Clamp(smoothedCenter.X, halfW, _videoWidth - halfW);
+        smoothedCenter.Y = Math.Clamp(smoothedCenter.Y, halfH, _videoHeight - halfH);
+
+        _cameraCenter.X = Math.Clamp(_cameraCenter.X, halfW, _videoWidth - halfW);
+        _cameraCenter.Y = Math.Clamp(_cameraCenter.Y, halfH, _videoHeight - halfH);
+
+        var x = (int)Math.Round(_cameraCenter.X - halfW);
+        var y = (int)Math.Round(_cameraCenter.Y - halfH);
+
+        x = Math.Clamp(x, 0, _videoWidth - _cropWidth);
+        y = Math.Clamp(y, 0, _videoHeight - _cropHeight);
+
+        _roi = new Rect(x, y, _cropWidth, _cropHeight);
+        _smoothedCenter = smoothedCenter;
+        _objectBox = objectBox;
+        _objectCenter = objectCenter;
+    }
+}

KalmanTracker.cs

@@ -1,6 +1,6 @@
 namespace splitter;
 
-internal sealed class KalmanTracker
+public sealed class KalmanTracker
 {
     // State vector: [x, y, vx, vy]
     private float[] _state = new float[4];

TrackingSplitter.cs

@@ -15,13 +15,6 @@ public class TrackingSplitter(
     private const int   LostFreezeFrames = 60; // 2 seconds at 30 FPS
     private const float CameraEasing     = 0.03f;
 
-    private enum TrackState
-    {
-        Tracking,
-        LostFreeze,
-        LostDrift
-    }
-
     public async Task TrackAndExtract(
         string srcFileName,
         string destFileName,
@@ -49,7 +42,6 @@ public class TrackingSplitter(
 
         Console.WriteLine($"[TrackingSplitter] skip={skip}, duration={duration}, fps={fps}, totalFrames={totalFrames}");
 
-        // encoder size depends on mode
         var encWidth  = debugOverlay ? videoWidth  : originalCropWidth;
         var encHeight = debugOverlay ? videoHeight : originalCropHeight;
 
@@ -64,23 +56,25 @@ public class TrackingSplitter(
 
         using var stdin = ffmpeg.StandardInput.BaseStream;
 
-        // Reusable frame and output mat
         using var frame     = new Mat();
         using var outputBgr = new Mat(encHeight, encWidth, MatType.CV_8UC3);
 
-        // Reusable raw video buffer
         var frameBytes  = encWidth * encHeight * 3;
         var videoBuffer = new byte[frameBytes];
 
         var kalman = new KalmanTracker();
-        kalman.Reset(new Point2f(videoWidth / 2f, videoHeight / 2f));
+        // initial reset is now done inside CameraController
 
-        var lostFrames       = 0;
+        var camera = new CameraController(
-        var reacquireCounter = 0; // kept for overlay display
+        videoWidth,
+        videoHeight,
+        originalCropWidth,
+        originalCropHeight,
+        kalman,
+        LostFreezeFrames,
+        CameraEasing);
 
-        var cameraCenter = new Point2f(videoWidth / 2f, videoHeight / 2f);
         var startTime = DateTime.UtcNow;
-        var state        = TrackState.Tracking;
 
         for (var i = 0; i < totalFrames; i++)
         {
@@ -93,109 +87,19 @@ public class TrackingSplitter(
             var objects = detector.DetectAll(frame, videoWidth, videoHeight);
             var primary = SelectTrackedObject(objects, kalman.LastMeasurement);
 
-            if (primary.HasValue)
+            camera.Update(primary);
-            {
-                objectCenter = primary.Value.center;
-                objectBox = primary.Value.box;
-            }
 
-            bool isLost = !objectCenter.HasValue;
+            objectBox = camera.ObjectBox;
+            objectCenter = camera.ObjectCenter;
 
-            // LOST / REACQUIRE STATE MACHINE
+            var smoothedCenter = camera.SmoothedCenter;
-            if (isLost)
+            var cameraCenter   = camera.CameraCenter;
-            {
+            var state          = camera.State;
-                lostFrames++;
+            var lostFrames     = camera.LostFrames;
-
+            var roi            = camera.Roi;
-                if (lostFrames <= LostFreezeFrames)
-                {
-                    // LOST_FREEZE: freeze camera
-                    state = TrackState.LostFreeze;
-                    objectCenter = null; // Kalman predicts but camera won't move
-                }
-                else
-                {
-                    // LOST_DRIFT: drift camera to center
-                    state = TrackState.LostDrift;
-                    objectCenter = new Point2f(videoWidth / 2f, videoHeight / 2f);
-                }
-            }
-            else
-            {
-                // Object reacquired
-                state = TrackState.Tracking;
-                lostFrames = 0;
-            }
-
-            // KALMAN + CAMERA UPDATE
-            Point2f smoothedCenter;
-
-            if (state == TrackState.Tracking)
-            {
-                smoothedCenter = kalman.Update(objectCenter);
-
-                float easing = 0.015f; // faster tracking
-                cameraCenter = new Point2f(
-                    cameraCenter.X + (smoothedCenter.X - cameraCenter.X) * easing,
-                    cameraCenter.Y + (smoothedCenter.Y - cameraCenter.Y) * easing);
-            }
-            else if (state == TrackState.LostFreeze)
-            {
-                // Freeze camera — do nothing
-                smoothedCenter = kalman.LastMeasurement ?? new Point2f(0, 0);
-            }
-            else // LOST_DRIFT
-            {
-                smoothedCenter = kalman.Update(objectCenter);
-
-                float driftEasing = 0.01f;
-                var fallbackCenter = new Point2f(videoWidth / 2f, videoHeight / 2f);
-
-                cameraCenter = new Point2f(
-                    cameraCenter.X + (fallbackCenter.X - cameraCenter.X) * driftEasing,
-                    cameraCenter.Y + (fallbackCenter.Y - cameraCenter.Y) * driftEasing);
-            }
-
-            var halfW = originalCropWidth  / 2f;
-            var halfH = originalCropHeight / 2f;
-
-            smoothedCenter.X = Math.Clamp(smoothedCenter.X, halfW, videoWidth - halfW);
-            smoothedCenter.Y = Math.Clamp(smoothedCenter.Y, halfH, videoHeight - halfH);
-
-            if (state == TrackState.Tracking)
-            {
-                smoothedCenter = kalman.Update(objectCenter);
-
-                cameraCenter = new Point2f(
-                    cameraCenter.X + (smoothedCenter.X - cameraCenter.X) * CameraEasing,
-                    cameraCenter.Y + (smoothedCenter.Y - cameraCenter.Y) * CameraEasing);
-            }
-            else if (state == TrackState.LostFreeze)
-            {
-                // Freeze camera — do nothing
-            }
-            else if (state == TrackState.LostDrift)
-            {
-                var fallbackCenter = new Point2f(videoWidth / 2f, videoHeight / 2f);
-
-                cameraCenter = new Point2f(
-                    cameraCenter.X + (fallbackCenter.X - cameraCenter.X) * 0.01f,
-                    cameraCenter.Y + (fallbackCenter.Y - cameraCenter.Y) * 0.01f);
-            }
-
-            cameraCenter.X = Math.Clamp(cameraCenter.X, halfW, videoWidth - halfW);
-            cameraCenter.Y = Math.Clamp(cameraCenter.Y, halfH, videoHeight - halfH);
-
-            var x = (int)Math.Round(cameraCenter.X - halfW);
-            var y = (int)Math.Round(cameraCenter.Y - halfH);
-
-            x = Math.Clamp(x, 0, videoWidth - originalCropWidth);
-            y = Math.Clamp(y, 0, videoHeight - originalCropHeight);
-
-            var roi = new Rect(x, y, originalCropWidth, originalCropHeight);
 
             if (debugOverlay)
             {
-                // overlays always drawn on frame
                 if (objectBox.HasValue)
                 {
                     var fb = objectBox.Value;
@@ -213,23 +117,18 @@ public class TrackingSplitter(
 
                 DrawText(frame, $"Faces: {objects.Count}", 20, 40, Scalar.White);
                 DrawText(frame, $"LostFrames: {lostFrames}", 20, 70, Scalar.White);
-                DrawText(frame, $"Reacquire: {reacquireCounter}", 20, 100, Scalar.White);
                 DrawText(frame, $"Noise: {kalman.CurrentNoise:F3}", 20, 130, Scalar.White);
                 DrawText(frame, $"Camera: {cameraCenter.X:F1},{cameraCenter.Y:F1}", 20, 160, Scalar.White);
             }
 
             if (debugOverlay)
             {
-                // DEBUG MODE: write FULL FRAME with overlays
-                // Ensure contiguous buffer by copying into preallocated outputBgr
                 frame.CopyTo(outputBgr);
-
                 Marshal.Copy(outputBgr.Data, videoBuffer, 0, frameBytes);
                 stdin.Write(videoBuffer, 0, frameBytes);
             }
             else
             {
-                // PRODUCTION MODE: actual crop
                 using var cropped = new Mat(frame, roi);
                 cropped.CopyTo(outputBgr);