diff --git a/Splitter-UI/Services/AutoDecisionService.cs b/Splitter-UI/Services/AutoDecisionService.cs
index aed8196..c7c3e64 100644
--- a/Splitter-UI/Services/AutoDecisionService.cs
+++ b/Splitter-UI/Services/AutoDecisionService.cs
@@ -2,12 +2,12 @@
 
 public sealed class AutoDecisionService(IThumbnailService _thumbnails, IFileProbeService _fileProbe, ILogger _log) : IAutoDecisionService
 {
-    public void ApplyAutoDecisions(JobViewModel job)
+    public void ApplyAutoDecisions(JobViewModel job, CancellationToken token)
     {
-        Task.Run(() => Detect(job));
+        Task.Run(() => Detect(job, token));
     }
 
-    private async Task Detect(JobViewModel job)
+    private async Task Detect(JobViewModel job, CancellationToken token)
     {
         try
         {
@@ -16,7 +16,7 @@ public sealed class AutoDecisionService(IThumbnailService _thumbnails, IFileProb
             job.Mask                   = "[NAME]_seg[NN].[EXT]";
             job.OutputFolder           = Path.Combine(Path.GetDirectoryName(job.InputFile)!, "splitter");
 
-            job.Probe           = await _fileProbe.ProbeAsync(job.InputFile);
+            job.Probe           = await _fileProbe.ProbeAsync(job.InputFile, token);
             job.Thumbnail       = await _thumbnails.CreateThumbnailAsync(job.InputFile, job.Probe, rotateDegree: job.Rotate);
 
             if (job.Probe.Width > job.Probe.Height)
@@ -29,7 +29,7 @@ public sealed class AutoDecisionService(IThumbnailService _thumbnails, IFileProb
             else
             {
                 var sampler         = new VideoRotationSampler(null);
-                job.Rotate = await sampler.DetectRotationAsync(job.InputFile, job.Probe.Duration);
+                job.Rotate = await sampler.DetectRotationAsync(job.InputFile, job.Probe.Duration, token);
                 job.Detect = job.Rotate == 0 ? null : "body";
             }
 
diff --git a/Splitter-UI/Services/FileProbeService.cs b/Splitter-UI/Services/FileProbeService.cs
index 13cb2d5..25980ba 100644
--- a/Splitter-UI/Services/FileProbeService.cs
+++ b/Splitter-UI/Services/FileProbeService.cs
@@ -2,9 +2,9 @@
 
 public sealed class FileProbeService : IFileProbeService
 {
-    public async Task<VideoInfo> ProbeAsync(string inputFile)
+    public async Task<VideoInfo> ProbeAsync(string inputFile, CancellationToken token)
     {
-        var res = await Task.Run(() => ProbeVideo.Probe(inputFile, false));
+        var res = await Task.Run(() => ProbeVideo.Probe(inputFile, false, token), token);
         return res;
     }
 }
diff --git a/Splitter-UI/Services/IAutoDecisionService.cs b/Splitter-UI/Services/IAutoDecisionService.cs
index 5793c2c..c760066 100644
--- a/Splitter-UI/Services/IAutoDecisionService.cs
+++ b/Splitter-UI/Services/IAutoDecisionService.cs
@@ -2,5 +2,5 @@
 
 public interface IAutoDecisionService
 {
-    void ApplyAutoDecisions(JobViewModel job);
+    void ApplyAutoDecisions(JobViewModel job, CancellationToken token);
 }
diff --git a/Splitter-UI/Services/IFileProbeService.cs b/Splitter-UI/Services/IFileProbeService.cs
index 8e60265..eee2cf1 100644
--- a/Splitter-UI/Services/IFileProbeService.cs
+++ b/Splitter-UI/Services/IFileProbeService.cs
@@ -2,5 +2,5 @@
 
 public interface IFileProbeService
 {
-    Task<VideoInfo> ProbeAsync(string inputFile);
+    Task<VideoInfo> ProbeAsync(string inputFile, CancellationToken token);
 }
diff --git a/Splitter-UI/ViewModels/FileListViewModel.cs b/Splitter-UI/ViewModels/FileListViewModel.cs
index 3fa2a55..abc51b1 100644
--- a/Splitter-UI/ViewModels/FileListViewModel.cs
+++ b/Splitter-UI/ViewModels/FileListViewModel.cs
@@ -34,7 +34,7 @@ public partial class FileListViewModel : ObservableObject
             var job = new SingleJob { InputFile = path };
             var vm = _factory.Create(job);
             Files.Add(vm);
-            _autoDecisionService.ApplyAutoDecisions(vm);
+            _autoDecisionService.ApplyAutoDecisions(vm, CancellationToken.None);
         }
 
         Selected = Files.LastOrDefault();
diff --git a/Splitter-UI/ViewModels/MainViewModel.cs b/Splitter-UI/ViewModels/MainViewModel.cs
index f80db4f..d5463e7 100644
--- a/Splitter-UI/ViewModels/MainViewModel.cs
+++ b/Splitter-UI/ViewModels/MainViewModel.cs
@@ -15,6 +15,8 @@ public partial class MainViewModel : ViewModelBase
     [ObservableProperty] private bool _transformMode = false;
     private ILogger _logger;
 
+    private CancellationTokenSource? _cancellationTokenSource;
+
     public MainViewModel(
         FileListViewModel fileListVM,
         PreviewPaneViewModel ppVM,
@@ -42,12 +44,19 @@ public partial class MainViewModel : ViewModelBase
             Inspector.Selected = file;
         };
 
+        Progress.SetMain(this);
         Inspector.SetMain(this);
         Inspector.Files = FileList.Files;
     }
 
+    public void Cancel()
+    {
+        _cancellationTokenSource?.Cancel();
+    }
+
     public async Task Start()
     {
+        _cancellationTokenSource = new CancellationTokenSource();
         try
         {
             StatusBar.StatusText = "Processing…";
@@ -59,23 +68,26 @@ public partial class MainViewModel : ViewModelBase
 
             foreach (var file in files)
             {
-                var fileJobs = await _processor.GenerateJobs(file.GetJob(), false);
+                var fileJobs = await _processor.GenerateJobs(file.GetJob(), false, _cancellationTokenSource.Token);
                 jobs.AddRange(fileJobs);
             }
 
-            await _processor.ProcessJobs(jobs, false);
+            await _processor.ProcessJobs(jobs, false, _cancellationTokenSource.Token);
         }
         catch (Exception ex)
         {
             // Handle exception
             StatusBar.StatusText = "Error occurred…";
             _logger.LogError($"Error: {ex.Message}");
+            _cancellationTokenSource.Cancel();
         }
         finally
         {
             StatusBar.StatusText = "Ready…";
             StatusBar.Percent    = 0;
             TransformMode        = false;
+
+            _cancellationTokenSource?.Dispose();
         }
     }
 
diff --git a/Splitter-UI/ViewModels/ProgressViewModel.cs b/Splitter-UI/ViewModels/ProgressViewModel.cs
index 5c96263..85dc8a3 100644
--- a/Splitter-UI/ViewModels/ProgressViewModel.cs
+++ b/Splitter-UI/ViewModels/ProgressViewModel.cs
@@ -1,5 +1,7 @@
 using System.Collections.ObjectModel;
 using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using Splitter_UI.Views;
 
 namespace Splitter_UI.ViewModels;
 
@@ -11,6 +13,20 @@ public partial class ProgressViewModel : ObservableObject
     public ObservableCollection<ProgressInfo> Processes { get; } = [];
 
     private Lock _lock = new();
+
+    private MainViewModel _mainModel = null!;
+
+    [RelayCommand]
+    private void Cancel()
+    {
+        _mainModel.Cancel();
+    }
+
+    public void SetMain(MainViewModel mainModel)
+    {
+        _mainModel = mainModel;
+    }
+
     public void ClearProgress(string name, int progressLine)
     {
         lock (_lock)
diff --git a/Splitter-UI/Views/ProgressView.axaml b/Splitter-UI/Views/ProgressView.axaml
index c443a74..4843ae9 100644
--- a/Splitter-UI/Views/ProgressView.axaml
+++ b/Splitter-UI/Views/ProgressView.axaml
@@ -5,20 +5,20 @@
     xmlns:vm="clr-namespace:Splitter_UI.ViewModels"
     x:DataType="vm:ProgressViewModel">
 
-    <Border Background="#111" Padding="8">
-        <ItemsControl ItemsSource="{Binding Processes}">
+    <Grid RowDefinitions="*,Auto" Background="#111">
+
+        <!-- Processes list -->
+        <ItemsControl Grid.Row="0" ItemsSource="{Binding Processes}">
             <ItemsControl.ItemTemplate>
                 <DataTemplate x:DataType="vm:ProgressInfo">
                     <Grid ColumnDefinitions="2*,3*,Auto,Auto"
                           Margin="0,2">
 
-                        <!-- Name -->
                         <TextBlock Grid.Column="0"
                                    Text="{Binding Name}"
                                    VerticalAlignment="Center"
                                    FontSize="12"/>
 
-                        <!-- Progress bar -->
                         <ProgressBar Grid.Column="1"
                                      Height="12"
                                      Minimum="0"
@@ -26,7 +26,6 @@
                                      Value="{Binding Progress}"
                                      Margin="8,0"/>
 
-                        <!-- ETA -->
                         <TextBlock Grid.Column="2"
                                    Width="70"
                                    Text="{Binding Eta, StringFormat={}{0:hh\\:mm\\:ss}}"
@@ -34,7 +33,6 @@
                                    Margin="12,0"
                                    FontSize="12"/>
 
-                        <!-- Speed -->
                         <TextBlock Grid.Column="3"
                                    Width="70"
                                    Text="{Binding Speed, StringFormat={}{0:0.00}}"
@@ -46,5 +44,20 @@
                 </DataTemplate>
             </ItemsControl.ItemTemplate>
         </ItemsControl>
-    </Border>
+
+        <!-- Bottom-right Cancel button -->
+        <StackPanel Grid.Row="1"
+                    Orientation="Horizontal"
+                    HorizontalAlignment="Right"
+                    Margin="0,12,0,0">
+
+            <Button Content="Cancel"
+                    Background="#700000"
+                    Foreground="White"
+                    Padding="12,6"
+                    Margin="0,0,10,10"
+                    Command="{Binding CancelCommand}"/>
+        </StackPanel>
+
+    </Grid>
 </UserControl>
diff --git a/splitter-cli/IJobProcessor.cs b/splitter-cli/IJobProcessor.cs
index 9e4cf94..8fc7e3c 100644
--- a/splitter-cli/IJobProcessor.cs
+++ b/splitter-cli/IJobProcessor.cs
@@ -2,6 +2,6 @@
 
 public interface IJobProcessor
 {
-    Task<List<SingleTask>> GenerateJobs(SingleJob job, bool estimateOnly);
-    Task<bool> ProcessJobs(List<SingleTask> tasks, bool singleThreaded);
+    Task<List<SingleTask>> GenerateJobs(SingleJob job, bool estimateOnly, CancellationToken token);
+    Task<bool> ProcessJobs(List<SingleTask> tasks, bool singleThreaded, CancellationToken token);
 }
\ No newline at end of file
diff --git a/splitter-cli/JobProcessor.cs b/splitter-cli/JobProcessor.cs
index f44102d..623074f 100644
--- a/splitter-cli/JobProcessor.cs
+++ b/splitter-cli/JobProcessor.cs
@@ -5,7 +5,7 @@ namespace splitter;
 
 public class JobProcessor(ILogger logger) : LoggingBase(logger, 0), IJobProcessor
 {
-    public async Task<List<SingleTask>> GenerateJobs(SingleJob job, bool estimateOnly)
+    public async Task<List<SingleTask>> GenerateJobs(SingleJob job, bool estimateOnly, CancellationToken token)
     {
         var baseName = Path.GetFileNameWithoutExtension(job.InputFile);
 
@@ -18,7 +18,14 @@ public class JobProcessor(ILogger logger) : LoggingBase(logger, 0), IJobProcesso
         if (!Directory.Exists(job.OutputFolder))
             Directory.CreateDirectory(job.OutputFolder);
 
-        var info = await ProbeVideo.Probe(job.InputFile, job.RotateAuto);
+        if (token.IsCancellationRequested)
+            return [];
+
+        var info = await ProbeVideo.Probe(job.InputFile, job.RotateAuto, token);
+
+        if (token.IsCancellationRequested)
+            return [];
+
         if (info.Duration <= 0)
         {
             LogError($"{baseName}: Could not read duration.");
@@ -88,18 +95,18 @@ public class JobProcessor(ILogger logger) : LoggingBase(logger, 0), IJobProcesso
         return jobs;
     }
 
-    public async Task<bool> ProcessJobs(List<SingleTask> tasks, bool singleThreaded)
+    public async Task<bool> ProcessJobs(List<SingleTask> tasks, bool singleThreaded, CancellationToken token)
     {
 
         if (singleThreaded)
         {
             LogInfo("Starting single-threaded splitting...");
-            await RunSingleThreaded(tasks);
+            await RunSingleThreaded(tasks, token);
         }
         else
         {
             LogInfo("Starting multi-threaded splitting...");
-            await RunMultiThreaded(tasks);
+            await RunMultiThreaded(tasks, token);
         }
 
         LogInfo("Done.");
@@ -116,7 +123,7 @@ public class JobProcessor(ILogger logger) : LoggingBase(logger, 0), IJobProcesso
     // Multi-threaded splitting
     // -----------------------------
 
-    private async Task RunMultiThreaded(List<SingleTask> jobs)
+    private async Task RunMultiThreaded(List<SingleTask> jobs, CancellationToken token)
     {
         LogProgress(0.0, TimeSpan.Zero, 0.0);
 
@@ -135,7 +142,7 @@ public class JobProcessor(ILogger logger) : LoggingBase(logger, 0), IJobProcesso
 
         foreach (var job in jobs)
         {
-            await sem.WaitAsync();
+            await sem.WaitAsync(token);
 
             tasks.Add(Task.Run(async () =>
             {
@@ -145,9 +152,12 @@ public class JobProcessor(ILogger logger) : LoggingBase(logger, 0), IJobProcesso
                 {
                     // Acquire a slot ID
                     while (!freeSlots.TryDequeue(out slot))
+                    {
+                        if ( token.IsCancellationRequested)
+                            return; 
                         await Task.Yield();
-
-                    await ProcessSegment(job, slot + 1);
+                    }
+                    await ProcessSegment(job, slot + 1, token);
 
                     var processed = Interlocked.Increment(ref processedSegments);
                     var elapsed   = sw.Elapsed;
@@ -174,21 +184,21 @@ public class JobProcessor(ILogger logger) : LoggingBase(logger, 0), IJobProcesso
     // Single-threaded splitting
     // -----------------------------
 
-    private async Task RunSingleThreaded(List<SingleTask> jobs)
+    private async Task RunSingleThreaded(List<SingleTask> jobs, CancellationToken token)
     {
         foreach (var job in jobs)
         {
-            await ProcessSegment(job, 0);
+            await ProcessSegment(job, 0, token);
         }
 
     }
 
-    private async Task ProcessSegment(SingleTask t, int slot)
+    private async Task ProcessSegment(SingleTask t, int slot, CancellationToken token)
     {
         var processor = t.ProcessorFactory(slot);
         try
         {
-            await processor.ProcessSegment(t);
+            await processor.ProcessSegment(t, token);
         }
         finally
         {
diff --git a/splitter-cli/SimpleSplitter.cs b/splitter-cli/SimpleSplitter.cs
index 3986ea1..9bee0c3 100644
--- a/splitter-cli/SimpleSplitter.cs
+++ b/splitter-cli/SimpleSplitter.cs
@@ -5,7 +5,7 @@ namespace splitter;
 
 public class SimpleSplitter(int segmentNo, ILogger logger) : LoggingBase(logger, segmentNo), ISegmentProcessor
 {
-    public async Task ProcessSegment(SingleTask job)
+    public async Task ProcessSegment(SingleTask job, CancellationToken token)
     {
         string inputFile                     = job.Job.InputFile;
         string outputFile                    = job.OutputFileName;
@@ -43,19 +43,19 @@ public class SimpleSplitter(int segmentNo, ILogger logger) : LoggingBase(logger,
 
         var psi = new ProcessStartInfo
         {
-            FileName = "ffmpeg",
-            Arguments = args,
+            FileName              = "ffmpeg",
+            Arguments             = args,
             RedirectStandardError = true,
-            UseShellExecute = false,
-            CreateNoWindow = true
+            UseShellExecute       = false,
+            CreateNoWindow        = true
         };
 
         using var proc = Process.Start(psi) ?? throw new Exception("Failed to start ffmpeg.");
 
         var name = Path.GetFileNameWithoutExtension(outputFile);
-        ShowFFMpegProgress(length, proc, name);
+        await ShowFFMpegProgress(length, proc, name, token);
 
-        proc.WaitForExit();
+        await proc.WaitForExitAsync(token);
         
         ClearProgress(name);
 
@@ -75,12 +75,12 @@ public class SimpleSplitter(int segmentNo, ILogger logger) : LoggingBase(logger,
         };
 
 
-    private void ShowFFMpegProgress(double length, Process proc, string name)
+    private async Task ShowFFMpegProgress(double length, Process proc, string name, CancellationToken token)
     {
         var sw = Stopwatch.StartNew();
 
         string? line;
-        while ((line = proc.StandardError.ReadLine()) != null)
+        while ((line = await proc.StandardError.ReadLineAsync(token)) != null)
         {
             // Look for "time=00:00:03.52"
             var idx = line.IndexOf("time=", StringComparison.OrdinalIgnoreCase);
diff --git a/splitter-cli/TrackingSplitter.cs b/splitter-cli/TrackingSplitter.cs
index 167ffaf..2ae3a9a 100644
--- a/splitter-cli/TrackingSplitter.cs
+++ b/splitter-cli/TrackingSplitter.cs
@@ -24,7 +24,7 @@ public class TrackingSplitter : LoggingBase, ISegmentProcessor, IDisposable
             d.Dispose();
     }
 
-    public async Task ProcessSegment(SingleTask job)
+    public async Task ProcessSegment(SingleTask job, CancellationToken token)
     {
         string inputFile                     = job.Job.InputFile;
         string outputFile                    = job.OutputFileName;
@@ -57,11 +57,11 @@ public class TrackingSplitter : LoggingBase, ISegmentProcessor, IDisposable
         LogInfo($"{name}: src={videoWidth}x{videoHeight} @ {fps:F3}fps, seg=[{start:F3},{length:F3}] enc={encWidth}x{encHeight}");
 
         // 2) Start FFmpeg decode (video only → raw BGR24 to stdout)
-        var decode = StartFfmpegDecode(inputFile, start, length, job.Job.Rotate, job.Job.PlainText);
+        var decode = await StartFfmpegDecode(inputFile, start, length, job.Job.Rotate, job.Job.PlainText, token);
         using var decodeStdout = decode.StandardOutput.BaseStream;
 
         // 3) Start FFmpeg encode (video from stdin + audio from original)
-        var encode = StartFfmpegEncode(
+        var encode = await StartFfmpegEncode(
             inputFile,
             outputFile,
             start,
@@ -70,7 +70,8 @@ public class TrackingSplitter : LoggingBase, ISegmentProcessor, IDisposable
             encHeight,
             fps,
             ffmpegPassthroughParameters,
-            job.Job.PlainText);
+            job.Job.PlainText,
+            token);
 
         using var encodeStdin = encode.StandardInput.BaseStream;
 
@@ -99,9 +100,11 @@ public class TrackingSplitter : LoggingBase, ISegmentProcessor, IDisposable
 
         while (frameIndex < totalFrames)
         {
+            token.ThrowIfCancellationRequested();
+
             frameIndex++;
 
-            var read = ReadExact(decodeStdout, inBuffer, 0, inBytes);
+            var read = await ReadExact(decodeStdout, inBuffer, 0, inBytes, token);
             if (read != inBytes)
                 break;
 
@@ -164,7 +167,7 @@ public class TrackingSplitter : LoggingBase, ISegmentProcessor, IDisposable
 
     // ---------- FFmpeg decode / encode ----------
 
-    private Process StartFfmpegDecode(string inputFile, double start, double length, int? rotate, bool plainText)
+    private async Task<Process> StartFfmpegDecode(string inputFile, double start, double length, int? rotate, bool plainText, CancellationToken token)
     {
         var ss = start .ToString("0.###", CultureInfo.InvariantCulture);
         var t  = length.ToString("0.###", CultureInfo.InvariantCulture);
@@ -192,12 +195,12 @@ public class TrackingSplitter : LoggingBase, ISegmentProcessor, IDisposable
 
         var fileName = Path.GetFileName(inputFile);
 
-        _ = Task.Run(() =>
+        _ = Task.Run(async () =>
         {
             try
             {
                 string? line;
-                while ((line = p.StandardError.ReadLine()) != null)
+                while ((line = await p.StandardError.ReadLineAsync(token)) != null)
                     if (plainText)
                         LogInfo($"[ffmpeg-decode] {fileName}: {line}");
             }
@@ -223,7 +226,7 @@ public class TrackingSplitter : LoggingBase, ISegmentProcessor, IDisposable
         return rotateStr;
     }
 
-    private Process StartFfmpegEncode(
+    private async Task<Process> StartFfmpegEncode(
         string inputFile,
         string outputFile,
         double start,
@@ -232,7 +235,8 @@ public class TrackingSplitter : LoggingBase, ISegmentProcessor, IDisposable
         int height,
         double fps,
         string[] passthrough,
-        bool plainText)
+        bool plainText,
+        CancellationToken token)
     {
         var pass   = passthrough.Length > 0 ? string.Join(" ", passthrough) : "";
         var fpsStr = fps.ToString("0.###", CultureInfo.InvariantCulture);
@@ -266,12 +270,12 @@ public class TrackingSplitter : LoggingBase, ISegmentProcessor, IDisposable
 
         var fileName = Path.GetFileName(outputFile);
 
-        _ = Task.Run(() =>
+        _ = Task.Run(async () =>
         {
             try
             {
                 string? line;
-                while ((line = p.StandardError.ReadLine()) != null)
+                while ((line = await p.StandardError.ReadLineAsync(token)) != null)
                 {
                     if (plainText)
                         LogInfo($"[ffmpeg-encode] {fileName}: {line}");
@@ -285,12 +289,12 @@ public class TrackingSplitter : LoggingBase, ISegmentProcessor, IDisposable
 
     // ---------- helpers ----------
 
-    private static int ReadExact(Stream s, byte[] buffer, int offset, int count)
+    private static async Task<int> ReadExact(Stream s, byte[] buffer, int offset, int count, CancellationToken token)
     {
         var total = 0;
         while (total < count)
         {
-            var read = s.Read(buffer, offset + total, count - total);
+            var read = await s.ReadAsync(buffer, offset + total, count - total, token);
             if (read <= 0)
                 break;
             total += read;
diff --git a/splitter-cli/algo/ISegmentProcessor.cs b/splitter-cli/algo/ISegmentProcessor.cs
index 68034f9..98329be 100644
--- a/splitter-cli/algo/ISegmentProcessor.cs
+++ b/splitter-cli/algo/ISegmentProcessor.cs
@@ -2,5 +2,5 @@
 
 public interface ISegmentProcessor
 {
-    Task ProcessSegment( SingleTask job );
+    Task ProcessSegment( SingleTask job, CancellationToken token);
 }
diff --git a/splitter-cli/probe/ProbeVideo.cs b/splitter-cli/probe/ProbeVideo.cs
index b5851d8..5dd578b 100644
--- a/splitter-cli/probe/ProbeVideo.cs
+++ b/splitter-cli/probe/ProbeVideo.cs
@@ -14,20 +14,20 @@ public static class ProbeVideo
         _ffprobeJsonOptions.Converters.Add(new FlexibleLongConverter());
     }
 
-    public static async Task<VideoInfo> Probe(string inputFile, bool detectRotation)
+    public static async Task<VideoInfo> Probe(string inputFile, bool detectRotation, CancellationToken token)
     {
-        var info = ProbeSize(inputFile);
+        var info = await ProbeSize(inputFile, token);
         if (detectRotation)
         {
-            var rotation = await ProbeRotation(inputFile, info.Duration);
+            var rotation = await ProbeRotation(inputFile, info.Duration, token);
             info = info with { Rotation = rotation };
         }
 
         return info;
     }
 
-    private static async Task<int> ProbeRotation(string inputFile, double duration)
-        => await new VideoRotationSampler(null).DetectRotationAsync(inputFile, duration);
+    private static async Task<int> ProbeRotation(string inputFile, double duration, CancellationToken token)
+        => await new VideoRotationSampler(null).DetectRotationAsync(inputFile, duration, token);
 
     private static readonly JsonSerializerOptions _ffprobeJsonOptions =
         new ()
@@ -39,7 +39,7 @@ public static class ProbeVideo
             UnknownTypeHandling         = JsonUnknownTypeHandling.JsonElement
         };
 
-    private static VideoInfo ProbeSize(string inputFile)
+    private static async Task<VideoInfo> ProbeSize(string inputFile, CancellationToken token)
     {
         var args =
             "-v error " +
@@ -61,8 +61,8 @@ public static class ProbeVideo
         using var p = new Process { StartInfo = psi };
         p.Start();
 
-        var json = p.StandardOutput.ReadToEnd();
-        p.WaitForExit();
+        var json = await p.StandardOutput.ReadToEndAsync(token);
+        await p.WaitForExitAsync(token);
 
         var result = JsonSerializer.Deserialize<FfprobeResult>(json, _ffprobeJsonOptions);
         var stream = result?.Streams?.FirstOrDefault();
diff --git a/splitter-cli/probe/VideoRotationSampler.cs b/splitter-cli/probe/VideoRotationSampler.cs
index 7542085..8566ac9 100644
--- a/splitter-cli/probe/VideoRotationSampler.cs
+++ b/splitter-cli/probe/VideoRotationSampler.cs
@@ -6,7 +6,7 @@ public sealed class VideoRotationSampler
 {
     private readonly FrameRotationDetector _detector = new FrameRotationDetector();
 
-    public static int    RotationDetectorSampleCount  = 20;
+    public static int    RotationDetectorSampleCount  = 10;
     public static double RotationDetectorSampleLength = 0.15;  // seconds to decode per probe
     public static int    RotationDetectorFrameWidth   = 320;
     public static int    RotationDetectorFrameHeight  = 180;
@@ -38,7 +38,8 @@ public sealed class VideoRotationSampler
 
     public async Task<int> DetectRotationAsync(
          string inputFile,
-         double videoLengthSeconds)
+         double videoLengthSeconds,
+         CancellationToken token)
     {
         if (videoLengthSeconds <= 0)
             return 0;
@@ -54,7 +55,8 @@ public sealed class VideoRotationSampler
                 t,
                 RotationDetectorSampleLength,
                 RotationDetectorFrameWidth,
-                RotationDetectorFrameHeight);
+                RotationDetectorFrameHeight,
+                token);
 
             if (frame != null && !frame.Empty())
             {
@@ -98,18 +100,21 @@ public sealed class VideoRotationSampler
         double start,
         double length,
         int width,
-        int height)
+        int height,
+        CancellationToken token)
     {
         var p = StartFfmpegDecode(inputFile, start, length, rotate: null, plainText: false);
 
-        int needed = _buffer.Length;
-        int read = 0;
+        var needed = _buffer.Length;
+        var read = 0;
 
         using var stdout = p.StandardOutput.BaseStream;
 
         while (read < needed)
         {
-            int r = await stdout.ReadAsync(_buffer, read, needed - read);
+            token.ThrowIfCancellationRequested();
+
+            var r = await stdout.ReadAsync(_buffer, read, needed - read, token);
             if (r == 0)
                 return null;
             read += r;
diff --git a/splitter-cli/splitter.cs b/splitter-cli/splitter.cs
index 72a279f..3d0970b 100644
--- a/splitter-cli/splitter.cs
+++ b/splitter-cli/splitter.cs
@@ -38,7 +38,7 @@ static partial class Program
         var allJobs = new List<SingleTask>();
         foreach ( var job in cmd.Jobs )
         {
-            var jobs = await processor.GenerateJobs(job, cmd.Master.EstimateOnly);
+            var jobs = await processor.GenerateJobs(job, cmd.Master.EstimateOnly, CancellationToken.None);
             allJobs.AddRange(jobs);
         }
 
@@ -49,7 +49,7 @@ static partial class Program
             return 0;
         }
 
-        var success = await processor.ProcessJobs(allJobs, cmd.Master.SingleThreaded);
+        var success = await processor.ProcessJobs(allJobs, cmd.Master.SingleThreaded, CancellationToken.None);
         if (uiTask != null)
         {
             if ( cts != null )