Initial version of face derecting crop functionality added. Should crop horizontal videos for YouTube shorts with face tracking.

.gitignore

@@ -361,3 +361,8 @@ MigrationBackup/
 
 # Fody - auto-generated XML schema
 FodyWeavers.xsd
+
+# OpenCV models
+*.onnx
+*.bin
+*.param

FaceKalmanTracker.cs

@@ -0,0 +1,101 @@
+namespace splitter;
+
+internal sealed class FaceKalmanTracker
+{
+    // State vector: [x, y, vx, vy]
+    private float[] _state = new float[4];
+
+    // Covariance matrix 4x4
+    private float[,] _p = new float[4, 4];
+
+    // Process noise (constant)
+    private const float _q = 1e-3f;
+
+    // Measurement noise (dynamic)
+    private float _r = 1e-1f;
+
+    // Identity matrix
+    private static readonly float[,] _i =
+    {
+        {1,0,0,0},
+        {0,1,0,0},
+        {0,0,1,0},
+        {0,0,0,1}
+    };
+
+    public Point2f? LastMeasurement { get; private set; }
+
+    public void Reset(Point2f initial)
+    {
+        _state[0] = initial.X;
+        _state[1] = initial.Y;
+        _state[2] = 0;
+        _state[3] = 0;
+
+        // Large initial uncertainty
+        for (int i = 0; i < 4; i++)
+            for (int j = 0; j < 4; j++)
+                _p[i, j] = (i == j) ? 1f : 0f;
+    }
+
+    public void SetMeasurementNoise(float r)
+    {
+        _r = r;
+    }
+
+    public Point2f Update(Point2f? measurement)
+    {
+        // --- PREDICTION ---
+        // State transition:
+        // x' = x + vx
+        // y' = y + vy
+        _state[0] += _state[2];
+        _state[1] += _state[3];
+
+        // Update covariance
+        AddProcessNoise();
+
+        if (measurement.HasValue)
+        {
+            // --- MEASUREMENT UPDATE ---
+            var z = measurement.Value;
+
+            // Innovation y = z - Hx
+            float yx = z.X - _state[0];
+            float yy = z.Y - _state[1];
+
+            // Innovation covariance S = P + R
+            float Sx = _p[0, 0] + _r;
+            float Sy = _p[1, 1] + _r;
+
+            // Kalman gain K = P / S
+            float Kx0 = _p[0, 0] / Sx;
+            float Kx1 = _p[1, 1] / Sy;
+
+            // Update state
+            _state[0] += Kx0 * yx;
+            _state[1] += Kx1 * yy;
+
+            // Velocity correction (helps reduce jitter)
+            _state[2] += 0.1f * Kx0 * yx;
+            _state[3] += 0.1f * Kx1 * yy;
+
+            // Update covariance: P = (I - K)P
+            _p[0, 0] *= (1 - Kx0);
+            _p[1, 1] *= (1 - Kx1);
+        }
+
+        LastMeasurement = measurement;
+
+        return new Point2f(_state[0], _state[1]);
+    }
+
+    private void AddProcessNoise()
+    {
+        // Add small noise to diagonal of covariance
+        _p[0, 0] += _q;
+        _p[1, 1] += _q;
+        _p[2, 2] += _q;
+        _p[3, 3] += _q;
+    }
+}

FaceTracker.cs

@@ -0,0 +1,328 @@
+using System.Diagnostics;
+using System.Runtime.InteropServices;
+using OpenCvSharp;
+using Cv = OpenCvSharp.Cv2;
+using Mat = OpenCvSharp.Mat;
+using CvPoint = OpenCvSharp.Point;
+using CvRect = OpenCvSharp.Rect;
+
+namespace splitter;
+
+public class FaceTracker
+{
+    public Action<double, TimeSpan, double> DrawProgress { get; init; } = (_, _, _) => { };
+
+    private static Rect ToCvRect(splitter.Rect r)
+        => new Rect(r.X, r.Y, r.Width, r.Height);
+
+    public async Task TrackFaceAndExtract(
+        string srcFileName,
+        string destFileName,
+        TimeSpan skip,
+        TimeSpan duration,
+        int cropWidth,
+        int cropHeight,
+        string[] passthrough,
+        bool debugOverlay)
+    {
+        // ------------------------------
+        // 1. OpenCV VideoCapture (stable)
+        // ------------------------------
+        using var capture = new VideoCapture(srcFileName);
+        if (!capture.IsOpened())
+            throw new Exception("Cannot open video");
+
+        capture.Set(VideoCaptureProperties.PosMsec, skip.TotalMilliseconds);
+
+        var videoWidth = (int)capture.Get(VideoCaptureProperties.FrameWidth);
+        var videoHeight = (int)capture.Get(VideoCaptureProperties.FrameHeight);
+        var fps = capture.Get(VideoCaptureProperties.Fps);
+        var totalFrames = (int)(duration.TotalSeconds * fps);
+
+        Console.WriteLine($"[FaceTracker] skip={skip}, duration={duration}, fps={fps}, totalFrames={totalFrames}");
+
+        // ------------------------------
+        // 2. UltraFaceDetector (new model)
+        // ------------------------------
+        using var detector = new UltraFaceDetector(
+            binPath: "slim_320.bin",
+            paramPath: "slim_320.param");
+
+        // ------------------------------
+        // 3. FFmpeg one-pass encoder
+        // ------------------------------
+        var ffmpeg = StartFfmpegNvenc(
+            srcFileName,
+            destFileName,
+            cropWidth,
+            cropHeight,
+            fps,
+            skip,
+            passthrough);
+
+        using var stdin = ffmpeg.StandardInput.BaseStream;
+
+        // ------------------------------
+        // 4. Tracking state
+        // ------------------------------
+        var frame = new Mat();
+        var kalman = new FaceKalmanTracker();
+        kalman.Reset(new Point2f(videoWidth / 2f, videoHeight / 2f));
+
+        var lostFrames = 0;
+        var wasLost = false;
+        var reacquireBoostFrames = 20;
+        var reacquireCounter = 0;
+
+        var cameraCenter = new Point2f(videoWidth / 2f, videoHeight / 2f);
+        var startTime = DateTime.UtcNow;
+
+        // ------------------------------
+        // 5. Main loop
+        // ------------------------------
+        for (var i = 0; i < totalFrames; i++)
+        {
+            if (!capture.Read(frame) || frame.Empty())
+                break;
+
+            // Ensure continuous memory for detector
+            Mat frameCont = frame.IsContinuous() ? frame : frame.Clone();
+
+            // Convert to byte[] for UltraFace
+            var bytesFull = frameCont.Rows * frameCont.Cols * frameCont.ElemSize();
+            var bufferFull = new byte[bytesFull];
+            Marshal.Copy(frameCont.Data, bufferFull, 0, bytesFull);
+
+            Rect? faceBox = null;
+            Point2f? faceCenter = null;
+
+            var faces = detector.DetectAll(bufferFull, videoWidth, videoHeight); // list of (box, center)
+
+            var primary = SelectTrackedFace(faces, kalman.LastMeasurement);
+
+            if (primary.HasValue)
+            {
+                faceCenter = primary.Value.center;
+                faceBox = primary.Value.box;
+            }
+
+
+            var isLost = !faceCenter.HasValue;
+
+            // LOST FACE → drift toward center
+            if (isLost)
+            {
+                lostFrames++;
+
+                var fallbackCenter = new Point2f(videoWidth / 2f, videoHeight / 2f);
+                var predicted = kalman.Update(null);
+
+                var t = Math.Min(1f, lostFrames / 60f);
+                var ease = 0.02f * t;
+
+                faceCenter = new Point2f(
+                    predicted.X * (1 - ease) + fallbackCenter.X * ease,
+                    predicted.Y * (1 - ease) + fallbackCenter.Y * ease);
+            }
+            else
+            {
+                if (wasLost)
+                    reacquireCounter = reacquireBoostFrames;
+
+                lostFrames = 0;
+            }
+
+            // SMOOTH REACQUISITION
+            if (reacquireCounter > 0)
+            {
+                var alpha = reacquireCounter / (float)reacquireBoostFrames;
+                var noise = 5e-2f + (1e-1f - 5e-2f) * (1 - alpha);
+                kalman.SetMeasurementNoise(noise);
+                reacquireCounter--;
+            }
+            else
+            {
+                kalman.SetMeasurementNoise(1e-1f);
+            }
+
+            wasLost = isLost;
+
+            var smoothedCenter = kalman.Update(faceCenter);
+
+            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);
+
+            // CAMERA EASING
+            var easing = 0.003f;
+            cameraCenter = new Point2f(
+                cameraCenter.X + (smoothedCenter.X - cameraCenter.X) * easing,
+                cameraCenter.Y + (smoothedCenter.Y - cameraCenter.Y) * easing);
+
+            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);
+
+            var roi = new CvRect(x, y, cropWidth, cropHeight);
+            
+            if (debugOverlay)
+            {
+                if (faceBox.HasValue)
+                {
+                    var fb = faceBox.Value;
+                    Cv.Rectangle(frameCont,
+                        new OpenCvSharp.Rect(fb.X, fb.Y, fb.Width, fb.Height),
+                        Scalar.LimeGreen, 2);
+                }
+
+                Cv.Circle(frameCont,
+                    new CvPoint((int)smoothedCenter.X, (int)smoothedCenter.Y),
+                    6, Scalar.LimeGreen, -1);
+
+                Cv.Rectangle(frameCont, roi,
+                    faceCenter.HasValue ? Scalar.Yellow : Scalar.Red, 3);
+            }
+
+            // Crop ROI
+            using var cropped = new Mat(frameCont, roi);
+
+            // Always clone to ensure contiguous memory
+            using var bgr = cropped.Clone();
+
+            // Write to FFmpeg
+            var bytes = bgr.Rows * bgr.Cols * bgr.ElemSize();
+            var buffer = new byte[bytes];
+            Marshal.Copy(bgr.Data, buffer, 0, bytes);
+            stdin.Write(buffer, 0, bytes);
+
+            // Dispose frameCont only if it was a clone
+            if (!ReferenceEquals(frameCont, frame))
+                frameCont.Dispose();
+
+            // Progress
+            var elapsed = DateTime.UtcNow - startTime;
+            var progress = (double)i / totalFrames;
+            var speed = i > 0 ? i / elapsed.TotalSeconds : 0.0;
+            var remainingFrames = totalFrames - i;
+            var etaSeconds = speed > 0 ? remainingFrames / speed : 0;
+            var eta = TimeSpan.FromSeconds(etaSeconds);
+
+            DrawProgress(progress, eta, speed);
+        }
+
+        stdin.Flush();
+        stdin.Close();
+
+        await ffmpeg.WaitForExitAsync();
+        if (ffmpeg.ExitCode != 0)
+            throw new Exception("FFmpeg NVENC encoding failed");
+    }
+
+    private (Rect box, Point2f center)? SelectTrackedFace(
+        List<(Rect box, Point2f center)> faces,
+        Point2f? previousCenter)
+    {
+        if (faces == null || faces.Count == 0)
+            return null;
+
+        if (!previousCenter.HasValue)
+        {
+            // no previous face → pick largest
+            return faces
+                .OrderByDescending(f => f.box.Width * f.box.Height)
+                .First();
+        }
+
+        // pick the face closest to previous center
+        return faces
+            .OrderBy(f =>
+            {
+                var dx = f.center.X - previousCenter.Value.X;
+                var dy = f.center.Y - previousCenter.Value.Y;
+                return dx * dx + dy * dy;
+            })
+            .First();
+    }
+
+    private Process StartFfmpegNvenc(
+        string srcFileName,
+        string destFileName,
+        int width,
+        int height,
+        double fps,
+        TimeSpan skip,
+        string[] passthrough)
+    {
+        var pass = passthrough.Length > 0 ? string.Join(" ", passthrough) : "";
+        var skipSeconds = skip.TotalSeconds.ToString("0.###", System.Globalization.CultureInfo.InvariantCulture);
+        var fpsStr = fps.ToString("0.###", System.Globalization.CultureInfo.InvariantCulture);
+
+        // One-pass pipeline:
+        //   - rawvideo from stdin
+        //   - audio from source MP4 (seeked)
+        //   - NVENC video encode
+        //   - AAC audio copy/encode
+        //
+        // This is the same structure your original OpenCV pipeline used.
+        //
+        // IMPORTANT:
+        //   Because OpenCV reliably reads the full segment,
+        //   FFmpeg will NOT close stdin early anymore.
+        //
+        var args =
+        "-y " +
+        // VIDEO INPUT (raw BGR24 from stdin)
+        $"-f rawvideo -pix_fmt bgr24 -s {width}x{height} -r {fpsStr} -i - " +
+
+        // AUDIO INPUT (seeked)
+        $"-ss {skipSeconds} -i \"{srcFileName}\" " +
+
+        // MAP streams
+        "-map 0:v:0 -map 1:a:0? -shortest " +
+
+        // VIDEO ENCODE
+        "-c:v h264_nvenc -preset p4 -b:v 8M -pix_fmt yuv420p " +
+
+        // AUDIO ENCODE/COPY
+        "-c:a aac -b:a 192k " +
+
+        // Extra passthrough flags
+        pass + $" \"{destFileName}\"";
+
+        var psi = new ProcessStartInfo
+        {
+            FileName = "ffmpeg",
+            Arguments = args,
+            RedirectStandardInput = true,
+            RedirectStandardError = true,
+            RedirectStandardOutput = true,
+            UseShellExecute = false,
+            CreateNoWindow = true
+        };
+
+        var process = new Process { StartInfo = psi };
+        process.Start();
+
+        // async stderr reader
+        _ = Task.Run(() =>
+        {
+            try
+            {
+                string? line;
+                while ((line = process.StandardError.ReadLine()) != null)
+                    Console.WriteLine($"[ffmpeg] {line}");
+            }
+            catch { }
+        });
+
+        return process;
+    }
+
+}

Point2f.cs

@@ -0,0 +1,13 @@
+namespace splitter;
+
+public struct Point2f
+{
+    public float X;
+    public float Y;
+
+    public Point2f(float x, float y)
+    {
+        X = x;
+        Y = y;
+    }
+}

Properties/launchSettings.json

@@ -0,0 +1,8 @@
+{
+  "profiles": {
+    "splitter": {
+      "commandName": "Project",
+      "commandLineArgs": "\"C:\\Users\\uncls\\Pictures\\2026\\2026 - Secret Rule\\20260426_212004.mp4\" \"C:\\Users\\uncls\\Pictures\\2026\\2026 - Secret Rule\\Shorts\" --crop --debug --text"
+    }
+  }
+}

README.md

@@ -26,6 +26,9 @@ This tool is intended for creators, archivists, and automation workflows that ne
 - FFmpeg and FFprobe installed and available in the system PATH
 - .NET 10 SDK or newer
 
+>Note: You must download YuNet ONNX model:
+https://github.com/opencv/opencv_zoo/tree/master/models/face_detection_yunet (github.com in Bing)
+
 ---
 
 ## Usage

Rect.cs

@@ -0,0 +1,17 @@
+namespace splitter;
+
+public struct Rect
+{
+    public int X;
+    public int Y;
+    public int Width;
+    public int Height;
+
+    public Rect(int x, int y, int w, int h)
+    {
+        X = x;
+        Y = y;
+        Width = w;
+        Height = h;
+    }
+}

UltraFaceDetector.cs

@@ -0,0 +1,133 @@
+using NcnnDotNet;
+using UltraFaceDotNet;
+
+namespace splitter;
+
+public sealed class UltraFaceDetector : IDisposable
+{
+    private readonly UltraFace _ultraFace;
+
+    public UltraFaceDetector(string binPath, string paramPath)
+    {
+        var param = new UltraFaceParameter
+        {
+            BinFilePath = binPath,
+            ParamFilePath = paramPath,
+            InputWidth = 320,
+            InputLength = 240,
+            NumThread = 1,
+            ScoreThreshold = 0.7f
+        };
+
+        _ultraFace = UltraFace.Create(param);
+    }
+
+    public (Rect box, Point2f center)? Detect(byte[] bgr, int width, int height)
+    {
+        if (bgr == null || bgr.Length == 0)
+            return null;
+
+        // bgr is contiguous BGR24: width * height * 3
+        unsafe
+        {
+            fixed (byte* p = bgr)
+            {
+                using var mat = Mat.FromPixels(
+                    (IntPtr)p,
+                    PixelType.Bgr,     // BGR24 input
+                    width,
+                    height);
+
+                var faces = _ultraFace.Detect(mat);
+                if (faces == null)
+                    return null;
+
+                FaceInfo best = default;
+                bool hasBest = false;
+
+                foreach (var f in faces)
+                {
+                    if (!hasBest || f.Score > best.Score)
+                    {
+                        best = f;
+                        hasBest = true;
+                    }
+                }
+
+                if (!hasBest)
+                    return null;
+
+                int x1 = (int)best.X1;
+                int y1 = (int)best.Y1;
+                int x2 = (int)best.X2;
+                int y2 = (int)best.Y2;
+
+                var rect = new Rect(
+                    x1,
+                    y1,
+                    x2 - x1,
+                    y2 - y1);
+
+                if (rect.Width <= 0 || rect.Height <= 0)
+                    return null;
+
+                var center = new Point2f(
+                    rect.X + rect.Width / 2f,
+                    rect.Y + rect.Height / 2f);
+
+                return (rect, center);
+            }
+        }
+    }
+
+    public List<(Rect box, Point2f center)> DetectAll(byte[] bgr, int width, int height)
+    {
+        var results = new List<(Rect box, Point2f center)>();
+
+        if (bgr == null || bgr.Length == 0)
+            return results;
+
+        unsafe
+        {
+            fixed (byte* p = bgr)
+            {
+                using var mat = Mat.FromPixels(
+                (IntPtr)p,
+                PixelType.Bgr,     // BGR24 input
+                width,
+                height);
+
+                var faces = _ultraFace.Detect(mat);
+                if (faces == null)
+                    return results;
+
+                foreach (var f in faces)
+                {
+                    int x1 = (int)f.X1;
+                    int y1 = (int)f.Y1;
+                    int x2 = (int)f.X2;
+                    int y2 = (int)f.Y2;
+
+                    var rect = new Rect(
+                    x1,
+                    y1,
+                    x2 - x1,
+                    y2 - y1);
+
+                    if (rect.Width <= 0 || rect.Height <= 0)
+                        continue;
+
+                    var center = new Point2f(
+                    rect.X + rect.Width / 2f,
+                    rect.Y + rect.Height / 2f);
+
+                    results.Add((rect, center));
+                }
+            }
+        }
+
+        return results;
+    }
+
+    public void Dispose() => _ultraFace?.Dispose();
+}

splitter.cs

@@ -1,23 +1,20 @@
-using System;
 using System.Diagnostics;
 using System.Globalization;
-using System.IO;
-using System.Linq;
 using System.Text;
-using System.Threading;
+using splitter;
-using System.Threading.Tasks;
 
 class Program
 {
     static int logLines = 0;
+    static bool plainText = false;
     static readonly object consoleLock = new();
     static bool progressRunning = true;
 
     static void Main(string[] args)
     {
         double? overrideTargetDuration = null;
-        bool estimateOnly = false;
+        var estimateOnly = false;
-        bool forceFixed = false;
+        var forceFixed = false;
 
 
         Console.OutputEncoding = Encoding.UTF8;
@@ -29,8 +26,8 @@ class Program
         }
 
         // Extract passthrough parameters after "--"
-        string[] passthrough = Array.Empty<string>();
+        var passthrough = Array.Empty<string>();
-        int passthroughIndex = Array.IndexOf(args, "--");
+        var passthroughIndex = Array.IndexOf(args, "--");
 
         if (passthroughIndex >= 0)
         {
@@ -47,9 +44,11 @@ class Program
             return;
         }
 
-        string inputFile = args[0];
+        var inputFile                 = args[0];
-        string outputFolder = args[1];
+        var outputFolder              = args[1];
+        (int width, int height)? crop = null;
         string? mask                  = null;
+        var debug                     = false;
 
         foreach (var arg in args.Skip(2))
         {
@@ -57,9 +56,25 @@ class Program
             {
                 mask = arg.Substring("--mask=".Length);
             }
+            else if (arg.StartsWith("--crop="))
+            {
+                crop = ParseCrop(arg.Substring("--crop=".Length));
+            }
+            else if (arg == "--crop")
+            {
+                crop = ParseCrop("");
+            }
+            else if (arg == "--text")
+            {
+                plainText = true;
+            }
+            else if (arg == "--debug")
+            {
+                debug = true;
+            }
             else if (arg.StartsWith("--duration="))
             {
-                string dur = arg.Substring("--duration=".Length);
+                var dur = arg.Substring("--duration=".Length);
                 overrideTargetDuration = ParseDuration(dur);
                 if (overrideTargetDuration <= 0)
                 {
@@ -86,19 +101,19 @@ class Program
         if (!Directory.Exists(outputFolder))
             Directory.CreateDirectory(outputFolder);
 
-        string baseName = Path.GetFileNameWithoutExtension(inputFile);
+        var baseName = Path.GetFileNameWithoutExtension(inputFile);
-        string outputMask = mask ?? $"{baseName}_Seg%03d.mp4";
+        var outputMask = mask ?? $"{baseName}_Seg%03d.mp4";
 
         LogInfo("Reading duration via ffprobe...");
 
-        double duration = GetDuration(inputFile);
+        var duration = GetDuration(inputFile);
         if (duration <= 0)
         {
             LogError("Could not read duration.");
             return;
         }
 
-        double target = overrideTargetDuration ?? 58.0;
+        var target = overrideTargetDuration ?? 58.0;
 
         int segments;
         double segmentLength;
@@ -132,9 +147,16 @@ class Program
         LogInfo($"Segments: {segments}");
         LogInfo($"Equal segment length: {segmentLength:F3}s");
 
+        if (crop != null)
+        {
+            LogInfo("Starting multi-threaded face tracking crop and splitting...");
+            RunMultiThreadedCrop(inputFile, outputFolder, outputMask, duration, segments, segmentLength, passthrough, crop.Value.width, crop.Value.height, debug);
+        }
+        else
+        {
             LogInfo("Starting multi-threaded ffmpeg splitting...");
-
             RunMultiThreadedSplit(inputFile, outputFolder, outputMask, duration, segments, segmentLength, passthrough);
+        }
 
         LogSuccess("Done.");
         progressRunning = false;
@@ -146,6 +168,32 @@ class Program
         }
     }
 
+    private static (int width, int height)? ParseCrop(string v)
+    {
+        // Default vertical Full HD for YouTube Shorts
+        const int defaultW = 607;
+        const int defaultH = 1080;
+
+        // Empty or whitespace → default crop
+        if (string.IsNullOrWhiteSpace(v))
+            return (defaultW, defaultH);
+
+        var s = v.Trim().ToLowerInvariant();
+
+        // Expected format: "WWWxHHH"
+        var parts = s.Split('x');
+        if (parts.Length != 2)
+            return null;
+
+        var okW = int.TryParse(parts[0], out var w);
+        var okH = int.TryParse(parts[1], out var h);
+
+        if (!okW || !okH || w <= 0 || h <= 0)
+            return null;
+
+        return (w, h);
+    }
+
     // -----------------------------
     // Logging + Progress UI
     // -----------------------------
@@ -153,6 +201,12 @@ class Program
     static void Log(string prefix, ConsoleColor color, string msg)
     {
         lock (consoleLock)
+        {
+            if (plainText)
+            {
+                Console.WriteLine($"{prefix} {msg}");
+            }
+            else
             {
                 Console.ForegroundColor = color;
                 Console.WriteLine($"{prefix} {msg}");
@@ -160,6 +214,7 @@ class Program
                 logLines++;
             }
         }
+    }
 
     static void LogInfo(string msg)    => Log("[INFO]", ConsoleColor.Cyan, msg);
     static void LogSuccess(string msg) => Log("[ OK ]", ConsoleColor.Green, msg);
@@ -168,15 +223,18 @@ class Program
 
     static void DrawProgress(double progress, TimeSpan eta, double speed)
     {
+        if ( plainText )
+            return;
+
         lock (consoleLock)
         {
-            int width = Math.Max(20, Console.WindowWidth - 20);
+            var width = Math.Max(20, Console.WindowWidth - 20);
-            int filled = (int)(progress * width);
+            var filled = (int)(progress * width);
             if (filled < 0) filled = 0;
             if (filled > width) filled = width;
 
-            int barLine = logLines + 1;
+            var barLine = logLines + 1;
-            int infoLine = logLines + 2;
+            var infoLine = logLines + 2;
 
             // Progress bar with 24-bit color (green)
             Console.SetCursorPosition(0, barLine);
@@ -187,14 +245,14 @@ class Program
 
             // Info line: percentage, ETA, speed
             Console.SetCursorPosition(0, infoLine);
-            string etaStr = eta.TotalSeconds < 0 || double.IsInfinity(eta.TotalSeconds)
+            var etaStr = eta.TotalSeconds < 0 || double.IsInfinity(eta.TotalSeconds)
                 ? "ETA: --:--"
                 : $"ETA: {eta:mm\\:ss}";
-            string speedStr = double.IsNaN(speed) || double.IsInfinity(speed)
+            var speedStr = double.IsNaN(speed) || double.IsInfinity(speed)
                 ? "Speed: -.-x"
                 : $"Speed: {speed:F2}x";
 
-            string info = $"{progress * 100:0.0}%  {etaStr}  {speedStr}   ";
+            var info = $"{progress * 100:0.0}%  {etaStr}  {speedStr}   ";
             Console.Write("\u001b[38;2;180;180;180m" + info.PadRight(Console.WindowWidth - 1) + "\u001b[0m");
         }
     }
@@ -215,11 +273,11 @@ class Program
         };
 
         using var proc = Process.Start(psi) ?? throw new Exception("Failed to start ffprobe.");
-        string? output = proc.StandardOutput.ReadToEnd();
+        var output = proc.StandardOutput.ReadToEnd();
         proc.WaitForExit();
 
         if (output != null &&
-            double.TryParse(output, NumberStyles.Any, CultureInfo.InvariantCulture, out double duration))
+            double.TryParse(output, NumberStyles.Any, CultureInfo.InvariantCulture, out var duration))
             return duration;
 
         return -1;
@@ -249,7 +307,7 @@ class Program
             })
             .ToList();
 
-        int completed = 0;
+        var completed = 0;
         var sw = Stopwatch.StartNew();
 
         // Progress thread
@@ -257,13 +315,13 @@ class Program
         {
             while (progressRunning)
             {
-                double progress = segments == 0 ? 0 : (double)completed / segments;
+                var progress = segments == 0 ? 0 : (double)completed / segments;
-                double processedSeconds = completed * segmentLength;
+                var processedSeconds = completed * segmentLength;
-                double speed = sw.Elapsed.TotalSeconds > 0
+                var speed = sw.Elapsed.TotalSeconds > 0
                     ? processedSeconds / sw.Elapsed.TotalSeconds
                     : 0;
 
-                double remainingSeconds = (totalDuration - processedSeconds) / Math.Max(speed, 0.0001);
+                var remainingSeconds = (totalDuration - processedSeconds) / Math.Max(speed, 0.0001);
                 if (remainingSeconds < 0) remainingSeconds = 0;
                 var eta = TimeSpan.FromSeconds(remainingSeconds);
 
@@ -276,14 +334,14 @@ class Program
         };
         progressThread.Start();
 
-        int maxDegree = Math.Max(1, Environment.ProcessorCount / 2);
+        var maxDegree = Math.Max(1, Environment.ProcessorCount / 2);
 
         Parallel.ForEach(
             jobs,
             new ParallelOptions { MaxDegreeOfParallelism = maxDegree },
             job =>
             {
-                string outputFile = BuildOutputFileName(outputFolder, mask, job.Index);
+                var outputFile = BuildOutputFileName(outputFolder, mask, job.Index);
                 RunFFmpegSegment(inputFile, outputFile, job.Start, job.Length, passthrough);
                 Interlocked.Increment(ref completed);
             });
@@ -294,6 +352,162 @@ class Program
         DrawProgress(1.0, TimeSpan.Zero, totalDuration / Math.Max(sw.Elapsed.TotalSeconds, 0.0001));
     }
 
+    static void RunSingleThreadedSplit(
+        string inputFile,
+        string outputFolder,
+        string mask,
+        double totalDuration,
+        int segments,
+        double segmentLength,
+        string[] passthrough)
+    {
+        var jobs = Enumerable.Range(0, segments)
+        .Select(i => new
+        {
+            Index = i,
+            Start = i * segmentLength,
+            Length = (i == segments - 1)
+                ? Math.Max(0.1, totalDuration - i * segmentLength)
+                : segmentLength
+        })
+        .ToList();
+
+        var completed = 0;
+        var sw = Stopwatch.StartNew();
+
+        // Progress thread
+        var progressThread = new Thread(() =>
+        {
+            while (progressRunning)
+            {
+                var progress = segments == 0 ? 0 : (double)completed / segments;
+                var processedSeconds = completed * segmentLength;
+                var speed = sw.Elapsed.TotalSeconds > 0
+                ? processedSeconds / sw.Elapsed.TotalSeconds
+                : 0;
+
+                var remainingSeconds = (totalDuration - processedSeconds) / Math.Max(speed, 0.0001);
+                if (remainingSeconds < 0) remainingSeconds = 0;
+                var eta = TimeSpan.FromSeconds(remainingSeconds);
+
+                DrawProgress(progress, eta, speed);
+                Thread.Sleep(200);
+            }
+        })
+        {
+            IsBackground = true
+        };
+        progressThread.Start();
+
+        // --- SINGLE THREADED LOOP ---
+        foreach (var job in jobs)
+        {
+            var outputFile = BuildOutputFileName(outputFolder, mask, job.Index);
+            RunFFmpegSegment(inputFile, outputFile, job.Start, job.Length, passthrough);
+            completed++;
+        }
+
+        sw.Stop();
+        progressRunning = false;
+        progressThread.Join();
+        DrawProgress(1.0, TimeSpan.Zero, totalDuration / Math.Max(sw.Elapsed.TotalSeconds, 0.0001));
+    }
+
+    // -----------------------------
+    // Multi-threaded cropping
+    // -----------------------------
+    private static void RunMultiThreadedCrop(
+        string inputFile,
+        string outputFolder,
+        string outputMask,
+        double duration,
+        int segments,
+        double segmentLength,
+        string[] passthrough,
+        int width,
+        int height,
+        bool showDebugOverlay)
+    {
+        var tracker = new FaceTracker
+        {
+            DrawProgress = DrawProgress
+        };
+
+        var jobs = Enumerable.Range(0, segments)
+        .Select(i => new
+        {
+            Index = i,
+            Start = i * segmentLength,
+            Length = (i == segments - 1)
+                ? Math.Max(0.1, duration - i * segmentLength)
+                : segmentLength
+        })
+        .ToList();
+
+        var completed = 0;
+        var sw = Stopwatch.StartNew();
+        progressRunning = true;
+
+        // --- PROGRESS THREAD ---
+        var progressThread = new Thread(() =>
+        {
+            while (progressRunning)
+            {
+                var progress = segments == 0 ? 0 : (double)completed / segments;
+                var processedSeconds = completed * segmentLength;
+
+                var speed = sw.Elapsed.TotalSeconds > 0
+                ? processedSeconds / sw.Elapsed.TotalSeconds
+                : 0;
+
+                var remainingSeconds = (duration - processedSeconds) / Math.Max(speed, 0.0001);
+                if (remainingSeconds < 0) remainingSeconds = 0;
+
+                var eta = TimeSpan.FromSeconds(remainingSeconds);
+
+                DrawProgress(progress, eta, speed);
+                Thread.Sleep(200);
+            }
+        })
+        {
+            IsBackground = true
+        };
+        progressThread.Start();
+
+        // --- PARALLEL EXECUTION ---
+        var maxDegree = Math.Max(1, Environment.ProcessorCount / 2);
+
+        Parallel.ForEach(
+            jobs,
+            new ParallelOptions { MaxDegreeOfParallelism = maxDegree },
+            async job =>
+            {
+                var outputFile = BuildOutputFileName(outputFolder, outputMask, job.Index);
+
+                // Run the face-tracking cropper
+                await tracker.TrackFaceAndExtract(
+                    inputFile,
+                    outputFile,
+                    TimeSpan.FromSeconds(job.Start),
+                    TimeSpan.FromSeconds(job.Length),
+                    width,
+                    height,
+                    passthrough,
+                    showDebugOverlay);
+
+                Interlocked.Increment(ref completed);
+            });
+
+        // --- CLEANUP ---
+        sw.Stop();
+        progressRunning = false;
+        progressThread.Join();
+
+        var finalSpeed = duration / Math.Max(sw.Elapsed.TotalSeconds, 0.0001);
+        DrawProgress(1.0, TimeSpan.Zero, finalSpeed);
+    }
+
+
     static string BuildOutputFileName(string folder, string mask, int index)
     {
         string fileName;
@@ -309,8 +523,8 @@ class Program
         else
         {
             // If no placeholder, append index
-            string name = Path.GetFileNameWithoutExtension(mask);
+            var name = Path.GetFileNameWithoutExtension(mask);
-            string ext = Path.GetExtension(mask);
+            var ext = Path.GetExtension(mask);
             fileName = $"{name}_{index:000}{ext}";
         }
 
@@ -319,9 +533,9 @@ class Program
 
     static void RunFFmpegSegment(string inputFile, string outputFile, double start, double length, string[] passthrough)
     {
-        string pass = passthrough.Length > 0 ? string.Join(" ", passthrough) : "";
+        var pass = passthrough.Length > 0 ? string.Join(" ", passthrough) : "";
 
-        string args =
+        var args =
             $"-ss {start.ToString(CultureInfo.InvariantCulture)} -i \"{inputFile}\" -t {length.ToString(CultureInfo.InvariantCulture)} -c copy {pass} \"{outputFile}\" -y";
 
         var psi = new ProcessStartInfo
@@ -343,7 +557,7 @@ class Program
         text = text.Trim().ToLowerInvariant();
 
         // Case 1: pure number to seconds
-        if (double.TryParse(text, NumberStyles.Any, CultureInfo.InvariantCulture, out double sec))
+        if (double.TryParse(text, NumberStyles.Any, CultureInfo.InvariantCulture, out var sec))
             return sec;
 
         // Case 2: Ns (seconds)
@@ -352,16 +566,16 @@ class Program
 
         // Case 3: NmMs (minutes + seconds)
         // Examples: 2m30s, 1m5s, 10m0s
-        int mIndex = text.IndexOf('m');
+        var mIndex = text.IndexOf('m');
-        int sIndex = text.IndexOf('s');
+        var sIndex = text.IndexOf('s');
 
         if (mIndex > 0 && sIndex > mIndex)
         {
-            string mPart = text[..mIndex];
+            var mPart = text[..mIndex];
-            string sPart = text[(mIndex + 1)..sIndex];
+            var sPart = text[(mIndex + 1)..sIndex];
 
-            if (double.TryParse(mPart, out double minutes) &&
+            if (double.TryParse(mPart, out var minutes) &&
-                double.TryParse(sPart, out double seconds))
+                double.TryParse(sPart, out var seconds))
             {
                 return minutes * 60 + seconds;
             }
@@ -406,15 +620,24 @@ Options:
   --estimate             Print calculated segment information and exit.
                          No splitting is performed.
 
+  --crop[=<w:h>]         Crop video to width w and height h, with face tracking.
+                         Useful to making YouTube Shorts or TikToks from horizontal video.
+                         Default: 607x1080 (vertical video cropped from Full HD original)
+
+  --text                 Display log in plain text.
+
+  --debug                Show debug overlay during face tracking.
+
 Passthrough:
   Anything after -- is passed directly to ffmpeg.
 
 Examples:
-  splitter video.mp4 out/
+  splitter vertical-video.mp4 out/
-  splitter video.mp4 out/ --duration=90s
+  splitter vertical-video.mp4 out/ --duration=90s
-  splitter video.mp4 out/ --duration=2m30s --mask=""Part%03d.mp4""
+  splitter vertical-video.mp4 out/ --duration=2m30s --mask=""Part%03d.mp4""
-  splitter video.mp4 out/ --estimate
+  splitter vertical-video.mp4 out/ --estimate
-  splitter video.mp4 out/ --force --duration=45 -- -an -sn
+  splitter vertical-video.mp4 out/ --force --duration=45 -- -an -sn
+  splitter horizontal-video.mp4 out/ --crop
 
 Description:
   Splits a video into equal or fixed-length segments using multi-threaded

splitter.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
@@ -6,7 +6,45 @@
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
     <LangVersion>latest</LangVersion>
-    <Optimize>true</Optimize>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
   </PropertyGroup>
 
+  <!-- DEBUG CONFIGURATION -->
+  <PropertyGroup Condition="'$(Configuration)' == 'Debug'">
+    <Optimize>false</Optimize>
+    <SelfContained>false</SelfContained>
+    <PublishSingleFile>false</PublishSingleFile>
+    <PublishTrimmed>false</PublishTrimmed>
+    <IncludeNativeLibrariesForSelfExtract>false</IncludeNativeLibrariesForSelfExtract>
+    <PublishReadyToRun>false</PublishReadyToRun>
+  </PropertyGroup>
+
+  <!-- RELEASE CONFIGURATION -->
+  <PropertyGroup Condition="'$(Configuration)' == 'Release'">
+    <Optimize>true</Optimize>
+    <SelfContained>true</SelfContained>
+    <PublishSingleFile>true</PublishSingleFile>
+    <PublishTrimmed>false</PublishTrimmed>
+    <!-- OpenCvSharp cannot be trimmed -->
+    <IncludeNativeLibrariesForSelfExtract>true</IncludeNativeLibrariesForSelfExtract>
+    <PublishReadyToRun>true</PublishReadyToRun>
+    <RuntimeIdentifier>win-x64</RuntimeIdentifier>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Content Include="slim_320.bin">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
+    <Content Include="slim_320.param">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="FFmpeg.AutoGen" Version="8.1.0" />
+    <PackageReference Include="OpenCvSharp4" Version="4.13.0.20260427" />
+    <PackageReference Include="OpenCvSharp4.runtime.win" Version="4.13.0.20260302" />
+    <PackageReference Include="UltraFaceDotNet" Version="1.0.0.2" />
+  </ItemGroup>
+
 </Project>