Add Shorts look preview and visual crop editor

Show opening/closing 9:16 stills from the same filtergraph, and let
users drag a keep-region on a source frame to fill the crop insets.

AmiReel.Tests/Models/SourceCropSelectionTests.cs

@@ -0,0 +1,100 @@
+using AmiReel.Models;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace AmiReel.Tests.Models;
+
+[TestClass]
+public class SourceCropSelectionTests
+{
+    [TestMethod]
+    public void FitUniform_WiderContainer_LetterboxesHorizontally()
+    {
+        // Act
+        (double offsetX, double offsetY, double width, double height) =
+            SourceCropSelection.FitUniform(400, 200, 100, 100);
+
+        // Assert
+        Assert.AreEqual(100, offsetX);
+        Assert.AreEqual(0, offsetY);
+        Assert.AreEqual(200, width);
+        Assert.AreEqual(200, height);
+    }
+
+    [TestMethod]
+    public void FitUniform_TallerContainer_LetterboxesVertically()
+    {
+        // Act
+        (double offsetX, double offsetY, double width, double height) =
+            SourceCropSelection.FitUniform(200, 400, 100, 100);
+
+        // Assert
+        Assert.AreEqual(0, offsetX);
+        Assert.AreEqual(100, offsetY);
+        Assert.AreEqual(200, width);
+        Assert.AreEqual(200, height);
+    }
+
+    [TestMethod]
+    public void ToInsets_FullFrameSelection_ReturnsEmptyInsets()
+    {
+        // Act
+        PixelInsets insets = SourceCropSelection.ToInsets(640, 512, 640, 512, 0, 0, 640, 512);
+
+        // Assert
+        Assert.IsTrue(insets.IsEmpty);
+    }
+
+    [TestMethod]
+    public void ToInsets_CenteredSelection_ComputesAllFourEdges()
+    {
+        // Act
+        PixelInsets insets = SourceCropSelection.ToInsets(100, 100, 100, 100, 10, 20, 70, 50);
+
+        // Assert
+        Assert.AreEqual(10, insets.Left);
+        Assert.AreEqual(20, insets.Right);
+        Assert.AreEqual(20, insets.Top);
+        Assert.AreEqual(30, insets.Bottom);
+    }
+
+    [TestMethod]
+    public void ToInsets_DraggedUpAndLeft_NormalizesTheRectangle()
+    {
+        // Act
+        PixelInsets insets = SourceCropSelection.ToInsets(100, 100, 100, 100, 80, 70, -70, -50);
+
+        // Assert
+        Assert.AreEqual(10, insets.Left);
+        Assert.AreEqual(20, insets.Right);
+        Assert.AreEqual(20, insets.Top);
+        Assert.AreEqual(30, insets.Bottom);
+    }
+
+    [TestMethod]
+    public void ToDisplayRect_RoundTripsKnownInsets()
+    {
+        // Arrange
+        PixelInsets insets = new(20, 20, 10, 10);
+
+        // Act
+        (double x, double y, double width, double height) =
+            SourceCropSelection.ToDisplayRect(100, 100, 200, 200, insets);
+
+        // Assert
+        Assert.AreEqual(40, x);
+        Assert.AreEqual(20, y);
+        Assert.AreEqual(120, width);
+        Assert.AreEqual(160, height);
+    }
+
+    [TestMethod]
+    public void ClampToDisplay_OutsideBounds_ClampsToEdges()
+    {
+        // Act
+        (double x, double y) = SourceCropSelection.ClampToDisplay(-8, 90, 80, 60);
+
+        // Assert
+        Assert.AreEqual(0, x);
+        Assert.AreEqual(60, y);
+    }
+}

AmiReel.Tests/Services/ShortsPipelineTests.cs

@@ -389,4 +389,128 @@ public class ShortsPipelineTests
         // Assert
         Assert.AreEqual(1000, width);
     }
+
+    [TestMethod]
+    public void ValidatePreview_WithMissingTitleAndOutput_DoesNotThrow()
+    {
+        // Arrange
+        string directory = CreateTempDirectory();
+        string input = Path.Combine(directory, "clip.mp4");
+        File.WriteAllText(input, "data");
+        ShortSettings settings = ValidSettings(input, Path.Combine(directory, "missing-font.ttf")) with
+        {
+            Title = "",
+            OutputPath = "",
+        };
+
+        // Act & Assert (no exception)
+        ShortsPipeline.ValidatePreview(settings);
+    }
+
+    [TestMethod]
+    public void ValidatePreview_WithMissingInput_ThrowsFileNotFoundException()
+    {
+        // Arrange
+        string directory = CreateTempDirectory();
+        ShortSettings settings = ValidSettings(Path.Combine(directory, "missing.mp4"), "font.ttf");
+
+        // Act & Assert
+        Assert.ThrowsExactly<FileNotFoundException>(() => ShortsPipeline.ValidatePreview(settings));
+    }
+
+    [TestMethod]
+    public void PreviewOverlayWindows_Opening_HidesTitleCard()
+    {
+        // Act
+        (double hookEnd, double infoStart, double ctaStart) = ShortsPipeline.PreviewOverlayWindows(ShortPreviewShot.Opening, 30);
+
+        // Assert
+        Assert.AreEqual(30, hookEnd);
+        Assert.AreEqual(31, infoStart);
+        Assert.AreEqual(31, ctaStart);
+    }
+
+    [TestMethod]
+    public void PreviewOverlayWindows_Closing_ShowsTitlesImmediately()
+    {
+        // Act
+        (double hookEnd, double infoStart, double ctaStart) = ShortsPipeline.PreviewOverlayWindows(ShortPreviewShot.Closing, 30);
+
+        // Assert
+        Assert.AreEqual(-1, hookEnd);
+        Assert.AreEqual(0, infoStart);
+        Assert.AreEqual(0, ctaStart);
+    }
+
+    [TestMethod]
+    public void PreviewSeekSeconds_OpeningAndClosing_StayInsideDuration()
+    {
+        // Act
+        double opening = ShortsPipeline.PreviewSeekSeconds(ShortPreviewShot.Opening, 30);
+        double closing = ShortsPipeline.PreviewSeekSeconds(ShortPreviewShot.Closing, 30);
+
+        // Assert
+        Assert.AreEqual(1.2, opening);
+        Assert.AreEqual(29.6, closing);
+    }
+
+    [TestMethod]
+    public void AddTimestampOffset_AddsFractionalSeconds()
+    {
+        // Act
+        string result = ShortsPipeline.AddTimestampOffset("00:01:10", 1.2);
+
+        // Assert
+        Assert.AreEqual("00:01:11.200", result);
+    }
+
+    [TestMethod]
+    public void BuildInputArguments_VideoStyle_IncludesLoopedBackgroundVideo()
+    {
+        // Arrange
+        ShortSettings settings = ValidSettings("in.mp4", "font.ttf", ShortStyle.Video) with
+        {
+            BackgroundVideo = @"D:\bg.mp4",
+        };
+
+        // Act
+        List<string> args = ShortsPipeline.BuildInputArguments(settings, 0.12, "00:00:01.200");
+
+        // Assert
+        CollectionAssert.Contains(args, "00:00:01.200");
+        CollectionAssert.Contains(args, "-stream_loop");
+        CollectionAssert.Contains(args, @"D:\bg.mp4");
+        CollectionAssert.Contains(args, "in.mp4");
+    }
+
+    [TestMethod]
+    public void BuildExtractFrameArguments_SeeksToStartAndWritesOnePng()
+    {
+        // Act
+        List<string> args = ShortsPipeline.BuildExtractFrameArguments(@"D:\clip.mp4", "00:00:05", @"C:\tmp\frame.png");
+
+        // Assert
+        CollectionAssert.Contains(args, "00:00:05");
+        CollectionAssert.Contains(args, @"D:\clip.mp4");
+        CollectionAssert.Contains(args, "-frames:v");
+        CollectionAssert.Contains(args, "1");
+        CollectionAssert.Contains(args, @"C:\tmp\frame.png");
+    }
+
+    [TestMethod]
+    public void BuildFilterComplex_WithoutTextOverlays_SkipsDrawtext()
+    {
+        // Act
+        string result = ShortsPipeline.BuildFilterComplex(
+            "[0:v]copy[base]",
+            fontEsc: "", hookEsc: "", titleEsc: "", metaEsc: "", websiteEsc: "",
+            hookEnd: 2.7, infoStart: 23, ctaStart: 26.5,
+            includeTextOverlays: false);
+
+        // Assert
+        StringAssert.Contains(result, "[0:v]copy[base]");
+        StringAssert.Contains(result, "[vout]");
+        Assert.IsFalse(result.Contains("drawtext", StringComparison.Ordinal));
+        Assert.IsFalse(result.Contains("drawbox", StringComparison.Ordinal));
+    }
 }

Controls/SourceCropEditor.xaml

@@ -0,0 +1,65 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<UserControl
+    x:Class="AmiReel.Controls.SourceCropEditor"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    mc:Ignorable="d">
+
+    <StackPanel Spacing="10" MinWidth="640">
+        <TextBlock x:Name="StatusText"
+                   Text="Drag on the frame to keep that region. The rest is cropped away."
+                   Style="{StaticResource MutedTextStyle}"
+                   TextWrapping="WrapWholeWords" />
+        <ProgressBar x:Name="LoadProgress"
+                     IsIndeterminate="True"
+                     Height="6"
+                     Visibility="Collapsed"
+                     AutomationProperties.Name="Loading source frame" />
+        <Border Background="{ThemeResource PageBrush}"
+                BorderBrush="{ThemeResource BorderBrush}"
+                BorderThickness="1"
+                CornerRadius="8">
+            <Grid x:Name="CropHost"
+                  Height="420"
+                  Background="Transparent"
+                  PointerPressed="CropHost_PointerPressed"
+                  PointerMoved="CropHost_PointerMoved"
+                  PointerReleased="CropHost_PointerReleased"
+                  PointerCaptureLost="CropHost_PointerCaptureLost"
+                  SizeChanged="CropHost_SizeChanged"
+                  AutomationProperties.Name="Source crop frame"
+                  AutomationProperties.AutomationId="SourceCropHost">
+                <Image x:Name="SourceImage"
+                       Stretch="Uniform"
+                       IsHitTestVisible="False"
+                       AutomationProperties.Name="Source video frame" />
+                <Canvas x:Name="OverlayCanvas" IsHitTestVisible="False">
+                    <Rectangle x:Name="SelectionRect"
+                               Stroke="{ThemeResource AccentBrush}"
+                               StrokeThickness="2"
+                               Fill="#33007ACC"
+                               Visibility="Collapsed" />
+                </Canvas>
+            </Grid>
+        </Border>
+        <Grid ColumnSpacing="10">
+            <Grid.ColumnDefinitions>
+                <ColumnDefinition Width="*" />
+                <ColumnDefinition Width="Auto" />
+            </Grid.ColumnDefinitions>
+            <TextBlock x:Name="InsetsText"
+                       Grid.Column="0"
+                       Text="Crop L0  R0  T0  B0"
+                       Style="{StaticResource MutedTextStyle}"
+                       VerticalAlignment="Center" />
+            <Button x:Name="ClearCropButton"
+                    Grid.Column="1"
+                    Content="Clear crop"
+                    Click="ClearCrop_Click"
+                    AutomationProperties.Name="Clear crop"
+                    AutomationProperties.AutomationId="ClearSourceCropButton" />
+        </Grid>
+    </StackPanel>
+</UserControl>

Controls/SourceCropEditor.xaml.cs

@@ -0,0 +1,174 @@
+using System.Runtime.InteropServices.WindowsRuntime;
+using AmiReel.Models;
+using AmiReel.Services;
+using Microsoft.UI.Input;
+using Microsoft.UI.Xaml;
+using Microsoft.UI.Xaml.Controls;
+using Microsoft.UI.Xaml.Input;
+using Microsoft.UI.Xaml.Media.Imaging;
+using Windows.Foundation;
+
+namespace AmiReel.Controls;
+
+public sealed partial class SourceCropEditor : UserControl
+{
+    private int _pixelWidth;
+    private int _pixelHeight;
+    private bool _isDragging;
+    private Point _dragStart;
+    private PixelInsets _insets;
+
+    public SourceCropEditor()
+    {
+        InitializeComponent();
+    }
+
+    public PixelInsets Insets => _insets;
+
+    public async Task LoadVideoFrameAsync(
+        string inputFile, string start, string ffmpegPath, string ffprobePath, CancellationToken token)
+    {
+        LoadProgress.Visibility = Visibility.Visible;
+        StatusText.Text = "Loading a source frame...";
+        try
+        {
+            string directory = Path.Combine(Path.GetTempPath(), "AmiReel", "crop-editor");
+            Directory.CreateDirectory(directory);
+            string framePath = Path.Combine(directory, "source-frame.png");
+            await new ShortsPipeline().ExtractSourceFrameAsync(
+                inputFile, start, ffmpegPath, ffprobePath, framePath, _ => { }, token);
+
+            await using FileStream stream = File.OpenRead(framePath);
+            BitmapImage bitmap = new();
+            await bitmap.SetSourceAsync(stream.AsRandomAccessStream());
+            SourceImage.Source = bitmap;
+            _pixelWidth = bitmap.PixelWidth;
+            _pixelHeight = bitmap.PixelHeight;
+            StatusText.Text = $"{_pixelWidth} × {_pixelHeight} · drag on the frame to choose the kept region.";
+            RefreshSelectionVisual();
+        }
+        finally
+        {
+            LoadProgress.Visibility = Visibility.Collapsed;
+        }
+    }
+
+    public void SetInsets(PixelInsets insets)
+    {
+        _insets = insets;
+        RefreshSelectionVisual();
+        UpdateInsetsText();
+    }
+
+    private void CropHost_PointerPressed(object sender, PointerRoutedEventArgs e)
+    {
+        if (_pixelWidth <= 0 || !TryMapToDisplay(e, out double x, out double y, out _, out _))
+            return;
+
+        _isDragging = true;
+        _dragStart = new Point(x, y);
+        CropHost.CapturePointer(e.Pointer);
+        UpdateDraftSelection(x, y);
+        e.Handled = true;
+    }
+
+    private void CropHost_PointerMoved(object sender, PointerRoutedEventArgs e)
+    {
+        if (!_isDragging)
+            return;
+        if (!TryMapToDisplay(e, out double x, out double y, out _, out _))
+            return;
+
+        UpdateDraftSelection(x, y);
+        e.Handled = true;
+    }
+
+    private void CropHost_PointerReleased(object sender, PointerRoutedEventArgs e)
+    {
+        if (!_isDragging)
+            return;
+
+        _isDragging = false;
+        CropHost.ReleasePointerCapture(e.Pointer);
+        if (TryMapToDisplay(e, out double x, out double y, out double displayWidth, out double displayHeight))
+            CommitSelection(x, y, displayWidth, displayHeight);
+        e.Handled = true;
+    }
+
+    private void CropHost_PointerCaptureLost(object sender, PointerRoutedEventArgs e)
+    {
+        _isDragging = false;
+    }
+
+    private void CropHost_SizeChanged(object sender, SizeChangedEventArgs e) => RefreshSelectionVisual();
+
+    private void ClearCrop_Click(object sender, RoutedEventArgs e) => SetInsets(default);
+
+    private bool TryMapToDisplay(
+        PointerRoutedEventArgs e, out double x, out double y, out double displayWidth, out double displayHeight)
+    {
+        (double offsetX, double offsetY, displayWidth, displayHeight) = CurrentFit();
+        x = 0;
+        y = 0;
+        if (displayWidth <= 0 || displayHeight <= 0)
+            return false;
+
+        PointerPoint point = e.GetCurrentPoint(CropHost);
+        (x, y) = SourceCropSelection.ClampToDisplay(
+            point.Position.X - offsetX, point.Position.Y - offsetY, displayWidth, displayHeight);
+        return true;
+    }
+
+    private void UpdateDraftSelection(double x, double y)
+    {
+        (double offsetX, double offsetY, double displayWidth, double displayHeight) = CurrentFit();
+        if (displayWidth <= 0)
+            return;
+
+        _insets = SourceCropSelection.ToInsets(
+            _pixelWidth, _pixelHeight, displayWidth, displayHeight,
+            _dragStart.X, _dragStart.Y, x - _dragStart.X, y - _dragStart.Y);
+        PlaceSelectionRect(offsetX, offsetY, displayWidth, displayHeight);
+        UpdateInsetsText();
+    }
+
+    private void CommitSelection(double x, double y, double displayWidth, double displayHeight)
+    {
+        _insets = SourceCropSelection.ToInsets(
+            _pixelWidth, _pixelHeight, displayWidth, displayHeight,
+            _dragStart.X, _dragStart.Y, x - _dragStart.X, y - _dragStart.Y);
+        RefreshSelectionVisual();
+        UpdateInsetsText();
+    }
+
+    private void RefreshSelectionVisual()
+    {
+        (double offsetX, double offsetY, double displayWidth, double displayHeight) = CurrentFit();
+        if (displayWidth <= 0 || _pixelWidth <= 0)
+        {
+            SelectionRect.Visibility = Visibility.Collapsed;
+            return;
+        }
+
+        PlaceSelectionRect(offsetX, offsetY, displayWidth, displayHeight);
+    }
+
+    private void PlaceSelectionRect(double offsetX, double offsetY, double displayWidth, double displayHeight)
+    {
+        (double x, double y, double width, double height) = SourceCropSelection.ToDisplayRect(
+            _pixelWidth, _pixelHeight, displayWidth, displayHeight, _insets);
+        Canvas.SetLeft(SelectionRect, offsetX + x);
+        Canvas.SetTop(SelectionRect, offsetY + y);
+        SelectionRect.Width = width;
+        SelectionRect.Height = height;
+        SelectionRect.Visibility = _insets.IsEmpty ? Visibility.Collapsed : Visibility.Visible;
+    }
+
+    private (double OffsetX, double OffsetY, double DisplayWidth, double DisplayHeight) CurrentFit() =>
+        SourceCropSelection.FitUniform(CropHost.ActualWidth, CropHost.ActualHeight, _pixelWidth, _pixelHeight);
+
+    private void UpdateInsetsText() =>
+        InsetsText.Text = _pixelWidth <= 0
+            ? "Crop L0  R0  T0  B0"
+            : $"Crop L{_insets.Left}  R{_insets.Right}  T{_insets.Top}  B{_insets.Bottom}  ·  {_pixelWidth - _insets.Left - _insets.Right}×{_pixelHeight - _insets.Top - _insets.Bottom}";
+}

MainPage.xaml

@@ -5,6 +5,7 @@
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    xmlns:controls="using:AmiReel.Controls"
     mc:Ignorable="d">
 
     <Grid x:Name="RootGrid" Padding="20" RowSpacing="16" Background="{ThemeResource PageBrush}">
@@ -87,7 +88,12 @@
         </Grid>
 
         <Border Grid.Row="1" Padding="18" Style="{StaticResource CardBorderStyle}" x:Name="ShortsContentPanel" Visibility="Collapsed">
-            <StackPanel Spacing="14">
+            <Grid ColumnSpacing="18">
+                <Grid.ColumnDefinitions>
+                    <ColumnDefinition Width="*" />
+                    <ColumnDefinition Width="Auto" />
+                </Grid.ColumnDefinitions>
+            <StackPanel Grid.Column="0" Spacing="14">
                 <StackPanel Spacing="4">
                     <TextBlock x:Name="ShortWizardTitleText" Text="Source clip" Style="{StaticResource SectionTitleStyle}" />
                     <TextBlock x:Name="ShortWizardStepText" Text="Step 1 of 4" Style="{StaticResource MutedTextStyle}" />
@@ -207,7 +213,7 @@
                             <ComboBoxItem Content="Auto (remove left/right black borders)" Tag="Auto" />
                             <ComboBoxItem Content="Center 4:3" Tag="Center" />
                         </ComboBox>
-                        <TextBlock Text="Manual crop overrides auto/center. Leave at 0 to use the mode above."
+                        <TextBlock Text="Manual crop overrides auto/center. Leave at 0 to use the mode above, or drag the kept region on a source frame."
                                    Style="{StaticResource MutedTextStyle}" TextWrapping="WrapWholeWords" />
                         <Grid ColumnSpacing="10">
                             <Grid.ColumnDefinitions>
@@ -225,6 +231,12 @@
                             <TextBox x:Name="ShortCropBottomBox" Grid.Column="3" Header="Crop bottom" Text="0"
                                      AutomationProperties.Name="Crop bottom pixels" />
                         </Grid>
+                        <Button x:Name="OpenCropEditorButton"
+                                Content="Crop visually..."
+                                Click="OpenCropEditor_Click"
+                                HorizontalAlignment="Left"
+                                AutomationProperties.Name="Open visual crop editor"
+                                AutomationProperties.AutomationId="OpenCropEditorButton" />
                     </StackPanel>
                 </StackPanel>
 
@@ -284,6 +296,56 @@
                     <TextBlock x:Name="ShortSummaryText" Text="" Style="{StaticResource MutedTextStyle}" TextWrapping="WrapWholeWords" />
                 </StackPanel>
             </StackPanel>
+
+                <StackPanel Grid.Column="1" Width="308" Spacing="10">
+                    <TextBlock Text="Preview" Style="{StaticResource SectionTitleStyle}" />
+                    <TextBlock x:Name="ShortPreviewStatusText"
+                               Text="Pick a source clip, then update the preview to see the 9:16 look."
+                               Style="{StaticResource MutedTextStyle}"
+                               TextWrapping="WrapWholeWords" />
+                    <Button x:Name="UpdateShortPreviewButton"
+                            Content="Update preview"
+                            Click="UpdateShortPreview_Click"
+                            HorizontalAlignment="Stretch"
+                            AutomationProperties.Name="Update short preview"
+                            AutomationProperties.AutomationId="UpdateShortPreviewButton" />
+                    <ProgressBar x:Name="ShortPreviewProgress"
+                                 IsIndeterminate="True"
+                                 Height="6"
+                                 Visibility="Collapsed"
+                                 AutomationProperties.Name="Preview progress" />
+                    <Grid ColumnSpacing="8">
+                        <Grid.ColumnDefinitions>
+                            <ColumnDefinition Width="*" />
+                            <ColumnDefinition Width="*" />
+                        </Grid.ColumnDefinitions>
+                        <StackPanel Spacing="6">
+                            <TextBlock Text="Opening" Style="{StaticResource MutedTextStyle}" />
+                            <Border Width="148" Height="263"
+                                    Background="{ThemeResource PageBrush}"
+                                    BorderBrush="{ThemeResource BorderBrush}"
+                                    BorderThickness="1"
+                                    CornerRadius="8">
+                                <Image x:Name="ShortPreviewOpeningImage"
+                                       Stretch="Uniform"
+                                       AutomationProperties.Name="Opening hook preview" />
+                            </Border>
+                        </StackPanel>
+                        <StackPanel Grid.Column="1" Spacing="6">
+                            <TextBlock Text="Closing" Style="{StaticResource MutedTextStyle}" />
+                            <Border Width="148" Height="263"
+                                    Background="{ThemeResource PageBrush}"
+                                    BorderBrush="{ThemeResource BorderBrush}"
+                                    BorderThickness="1"
+                                    CornerRadius="8">
+                                <Image x:Name="ShortPreviewClosingImage"
+                                       Stretch="Uniform"
+                                       AutomationProperties.Name="Closing title-card preview" />
+                            </Border>
+                        </StackPanel>
+                    </Grid>
+                </StackPanel>
+            </Grid>
         </Border>
 
         <Border x:Name="RenderProgressPanel"
@@ -352,6 +414,24 @@
             </StackPanel>
         </Grid>
 
+        <ContentDialog x:Name="CropEditorDialog"
+                       Title="Crop source"
+                       PrimaryButtonText="Use this crop"
+                       CloseButtonText="Cancel"
+                       DefaultButton="Primary"
+                       Background="{ThemeResource PanelBrush}"
+                       Foreground="{ThemeResource TextBrush}"
+                       BorderBrush="{ThemeResource HeroBorderBrush}"
+                       BorderThickness="1.5"
+                       CornerRadius="18"
+                       PrimaryButtonStyle="{StaticResource DialogPrimaryButtonStyle}"
+                       CloseButtonStyle="{StaticResource DialogCloseButtonStyle}">
+            <ContentDialog.Resources>
+                <x:Double x:Key="ContentDialogMaxWidth">920</x:Double>
+            </ContentDialog.Resources>
+            <controls:SourceCropEditor x:Name="ShortCropEditor" />
+        </ContentDialog>
+
         <ContentDialog x:Name="SettingsDialog"
                        Title="Settings"
                        PrimaryButtonText="Done"

MainPage.xaml.cs

@@ -1,11 +1,13 @@
 using System.Collections.ObjectModel;
 using System.Diagnostics;
 using System.Globalization;
+using System.Runtime.InteropServices.WindowsRuntime;
 using System.Text;
 using AmiReel.Models;
 using AmiReel.Services;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
+using Microsoft.UI.Xaml.Media.Imaging;
 using Windows.ApplicationModel.DataTransfer;
 using Windows.Storage;
 using Windows.Storage.Pickers;
@@ -27,6 +29,8 @@ public sealed partial class MainPage : Page
     private bool _keepRenderOutput;
     private List<ShortWizardStep> _wizardSteps = [.. ShortWizard.StepsFor(ShortStyle.Brand)];
     private int _wizardIndex;
+    private int _previewGeneration;
+    private string? _previewDirectory;
 
     public MainPage()
     {
@@ -150,6 +154,8 @@ public sealed partial class MainPage : Page
             ShortSummaryText.Text = BuildShortSummary();
 
         UpdateWizardNavigation();
+        if (IsLoaded && step != ShortWizardStep.Clip)
+            _ = RefreshShortPreviewAsync(automatic: true);
     }
 
     private void UpdateWizardNavigation()
@@ -593,12 +599,126 @@ public sealed partial class MainPage : Page
             ShortFontBox.Text = file.Path;
     }
 
+    private async void OpenCropEditor_Click(object sender, RoutedEventArgs e)
+    {
+        string input = ShortInputBox.Text.Trim();
+        if (string.IsNullOrWhiteSpace(input) || !File.Exists(input))
+        {
+            await ShowMessageAsync("Crop source", "Select a valid source video first.");
+            return;
+        }
+
+        try
+        {
+            CropEditorDialog.XamlRoot = XamlRoot;
+            CropEditorDialog.RequestedTheme = ActualTheme;
+            await ShortCropEditor.LoadVideoFrameAsync(
+                input,
+                string.IsNullOrWhiteSpace(ShortStartBox.Text) ? "00:00:00" : ShortStartBox.Text.Trim(),
+                FfmpegPathBox.Text.Trim(),
+                FfprobePathBox.Text.Trim(),
+                CancellationToken.None);
+            ShortCropEditor.SetInsets(ReadCropInsets());
+
+            ContentDialogResult result = await CropEditorDialog.ShowAsync();
+            if (result != ContentDialogResult.Primary)
+                return;
+
+            PixelInsets insets = ShortCropEditor.Insets;
+            ShortCropLeftBox.Text = insets.Left.ToString(CultureInfo.InvariantCulture);
+            ShortCropRightBox.Text = insets.Right.ToString(CultureInfo.InvariantCulture);
+            ShortCropTopBox.Text = insets.Top.ToString(CultureInfo.InvariantCulture);
+            ShortCropBottomBox.Text = insets.Bottom.ToString(CultureInfo.InvariantCulture);
+        }
+        catch (Exception exception)
+        {
+            await ShowMessageAsync("Crop source", UserFacingErrors.Summarize(exception));
+        }
+    }
+
+    private PixelInsets ReadCropInsets()
+    {
+        static int ReadBox(string text)
+        {
+            return int.TryParse(text, NumberStyles.Integer, CultureInfo.InvariantCulture, out int value) && value > 0
+                ? value
+                : 0;
+        }
+
+        return new PixelInsets(
+            ReadBox(ShortCropLeftBox.Text),
+            ReadBox(ShortCropRightBox.Text),
+            ReadBox(ShortCropTopBox.Text),
+            ReadBox(ShortCropBottomBox.Text));
+    }
+
     private async void PreviewShortSource_Click(object sender, RoutedEventArgs e)
     {
         if (!string.IsNullOrWhiteSpace(ShortInputBox.Text))
             await OpenPreviewAsync(ShortInputBox.Text.Trim());
     }
 
+    private async void UpdateShortPreview_Click(object sender, RoutedEventArgs e) =>
+        await RefreshShortPreviewAsync(automatic: false);
+
+    private async Task RefreshShortPreviewAsync(bool automatic)
+    {
+        if (_isRendering)
+            return;
+
+        int generation = ++_previewGeneration;
+        ShortPreviewProgress.Visibility = Visibility.Visible;
+        UpdateShortPreviewButton.IsEnabled = false;
+        ShortPreviewStatusText.Text = "Rendering 9:16 preview frames...";
+
+        try
+        {
+            ShortSettings settings = ReadShortSettings();
+            ShortsPipeline.ValidatePreview(settings);
+            _previewDirectory ??= Path.Combine(Path.GetTempPath(), "AmiReel", "short-preview", Guid.NewGuid().ToString("N"));
+            Directory.CreateDirectory(_previewDirectory);
+
+            ShortPreviewFrames frames = await new ShortsPipeline().RenderPreviewAsync(
+                settings, _previewDirectory, _ => { }, CancellationToken.None);
+
+            if (generation != _previewGeneration)
+                return;
+
+            ShortPreviewOpeningImage.Source = await LoadPreviewBitmapAsync(frames.OpeningPath);
+            ShortPreviewClosingImage.Source = await LoadPreviewBitmapAsync(frames.ClosingPath);
+            bool hasFont = !string.IsNullOrWhiteSpace(settings.FontFile) && File.Exists(settings.FontFile);
+            ShortPreviewStatusText.Text = hasFont
+                ? $"{settings.Style} · opening hook and closing title card"
+                : "Look only — pick a font on the last step to include the title-card text.";
+        }
+        catch (Exception exception)
+        {
+            if (generation != _previewGeneration)
+                return;
+
+            string message = UserFacingErrors.Summarize(exception);
+            ShortPreviewStatusText.Text = message;
+            if (!automatic)
+                await ShowMessageAsync("Preview failed", message);
+        }
+        finally
+        {
+            if (generation == _previewGeneration)
+            {
+                ShortPreviewProgress.Visibility = Visibility.Collapsed;
+                UpdateShortPreviewButton.IsEnabled = true;
+            }
+        }
+    }
+
+    private static async Task<BitmapImage> LoadPreviewBitmapAsync(string path)
+    {
+        await using FileStream stream = File.OpenRead(path);
+        BitmapImage bitmap = new() { DecodePixelWidth = 296 };
+        await bitmap.SetSourceAsync(stream.AsRandomAccessStream());
+        return bitmap;
+    }
+
     private void SetRendering(bool rendering)
     {
         _isRendering = rendering;

Models/ShortSettings.cs

@@ -32,6 +32,16 @@ public enum ShortSourceCropMode
     Center,
 }
 
+/// <summary>Which moment of the Short a preview still represents.</summary>
+public enum ShortPreviewShot
+{
+    Opening,
+    Closing,
+}
+
+/// <summary>PNG stills of the opening hook and closing title card.</summary>
+public sealed record ShortPreviewFrames(string OpeningPath, string ClosingPath);
+
 /// <summary>One YouTube Shorts render job's parameters (port of amigadb-short-fx-v4.sh).</summary>
 public sealed record ShortSettings
 {

Models/SourceCropSelection.cs

@@ -0,0 +1,111 @@
+namespace AmiReel.Models;
+
+/// <summary>Edge insets, in source pixels, removed by a manual crop.</summary>
+public readonly record struct PixelInsets(int Left, int Right, int Top, int Bottom)
+{
+    public bool IsEmpty => Left == 0 && Right == 0 && Top == 0 && Bottom == 0;
+}
+
+/// <summary>Maps a dragged display rectangle onto source-pixel crop insets.</summary>
+public static class SourceCropSelection
+{
+    public const int MinimumSize = 16;
+
+    public static (double OffsetX, double OffsetY, double DisplayWidth, double DisplayHeight) FitUniform(
+        double containerWidth, double containerHeight, int pixelWidth, int pixelHeight)
+    {
+        if (containerWidth <= 0 || containerHeight <= 0 || pixelWidth <= 0 || pixelHeight <= 0)
+            return (0, 0, 0, 0);
+
+        double containerAspect = containerWidth / containerHeight;
+        double imageAspect = pixelWidth / (double)pixelHeight;
+        double displayWidth;
+        double displayHeight;
+        if (containerAspect > imageAspect)
+        {
+            displayHeight = containerHeight;
+            displayWidth = containerHeight * imageAspect;
+        }
+        else
+        {
+            displayWidth = containerWidth;
+            displayHeight = containerWidth / imageAspect;
+        }
+
+        return ((containerWidth - displayWidth) / 2, (containerHeight - displayHeight) / 2, displayWidth, displayHeight);
+    }
+
+    public static PixelInsets ToInsets(
+        int pixelWidth,
+        int pixelHeight,
+        double displayWidth,
+        double displayHeight,
+        double x,
+        double y,
+        double width,
+        double height)
+    {
+        if (pixelWidth <= 0 || pixelHeight <= 0 || displayWidth <= 0 || displayHeight <= 0)
+            return default;
+
+        Normalize(ref x, ref y, ref width, ref height);
+        x = Math.Clamp(x, 0, displayWidth);
+        y = Math.Clamp(y, 0, displayHeight);
+        width = Math.Clamp(width, 0, displayWidth - x);
+        height = Math.Clamp(height, 0, displayHeight - y);
+
+        double scaleX = pixelWidth / displayWidth;
+        double scaleY = pixelHeight / displayHeight;
+        int left = ToEvenPixel(x * scaleX, pixelWidth - MinimumSize);
+        int top = ToEvenPixel(y * scaleY, pixelHeight - MinimumSize);
+        int right = ToEvenPixel((displayWidth - x - width) * scaleX, pixelWidth - MinimumSize - left);
+        int bottom = ToEvenPixel((displayHeight - y - height) * scaleY, pixelHeight - MinimumSize - top);
+
+        if (pixelWidth - left - right < MinimumSize)
+            right = Math.Max(0, pixelWidth - left - MinimumSize);
+        if (pixelHeight - top - bottom < MinimumSize)
+            bottom = Math.Max(0, pixelHeight - top - MinimumSize);
+
+        return new PixelInsets(left, right, top, bottom);
+    }
+
+    public static (double X, double Y, double Width, double Height) ToDisplayRect(
+        int pixelWidth, int pixelHeight, double displayWidth, double displayHeight, PixelInsets insets)
+    {
+        if (pixelWidth <= 0 || pixelHeight <= 0 || displayWidth <= 0 || displayHeight <= 0)
+            return (0, 0, Math.Max(0, displayWidth), Math.Max(0, displayHeight));
+
+        double scaleX = displayWidth / pixelWidth;
+        double scaleY = displayHeight / pixelHeight;
+        double x = insets.Left * scaleX;
+        double y = insets.Top * scaleY;
+        double width = Math.Max(1, (pixelWidth - insets.Left - insets.Right) * scaleX);
+        double height = Math.Max(1, (pixelHeight - insets.Top - insets.Bottom) * scaleY);
+        return (x, y, width, height);
+    }
+
+    public static (double X, double Y) ClampToDisplay(double x, double y, double displayWidth, double displayHeight) =>
+        (Math.Clamp(x, 0, Math.Max(0, displayWidth)), Math.Clamp(y, 0, Math.Max(0, displayHeight)));
+
+    private static void Normalize(ref double x, ref double y, ref double width, ref double height)
+    {
+        if (width < 0)
+        {
+            x += width;
+            width = -width;
+        }
+
+        if (height < 0)
+        {
+            y += height;
+            height = -height;
+        }
+    }
+
+    private static int ToEvenPixel(double value, int max)
+    {
+        int rounded = (int)Math.Round(value, MidpointRounding.AwayFromZero);
+        int clamped = Math.Clamp(rounded, 0, Math.Max(0, max));
+        return (clamped / 2) * 2;
+    }
+}

Services/ShortsPipeline.cs

@@ -65,11 +65,7 @@ public sealed class ShortsPipeline
                 websiteEsc: EscapeFfmpegPath(websiteFile),
                 hookEnd, infoStart, ctaStart);
 
-            List<string> args = ["-hide_banner", "-y", "-ss", settings.Start, "-t", F(duration), "-i", settings.InputFile];
+            List<string> args = BuildInputArguments(settings, duration);
-            if (settings.Style == ShortStyle.Brand)
-                args.AddRange(["-loop", "1", "-i", settings.BackgroundImage]);
-            if (settings.Style == ShortStyle.Video)
-                args.AddRange(["-stream_loop", "-1", "-i", settings.BackgroundVideo]);
 
             args.AddRange([
                 "-filter_complex", filterComplex,
@@ -107,6 +103,78 @@ public sealed class ShortsPipeline
         }
     }
 
+    /// <summary>
+    /// Renders two 9:16 stills with the same filtergraph as the final Short: opening hook and closing title card.
+    /// </summary>
+    public async Task<ShortPreviewFrames> RenderPreviewAsync(
+        ShortSettings settings, string outputDirectory, Action<string> log, CancellationToken token)
+    {
+        ValidatePreview(settings);
+        ToolPaths tools = await ToolExtractor.ResolveAsync(settings.FfmpegPath, settings.FfprobePath, token);
+        Directory.CreateDirectory(outputDirectory);
+
+        string workDir = Path.Combine(outputDirectory, "meta");
+        Directory.CreateDirectory(workDir);
+
+        string hookFile = WriteTextFile(workDir, "hook.txt", string.IsNullOrWhiteSpace(settings.Hook) ? "THIS RAN ON AN AMIGA" : settings.Hook);
+        string titleFile = WriteTextFile(workDir, "title.txt", string.IsNullOrWhiteSpace(settings.Title) ? "TITLE" : settings.Title);
+        string metaFile = WriteTextFile(workDir, "meta.txt", BuildMeta(settings));
+        string websiteFile = WriteTextFile(workDir, "website.txt", string.IsNullOrWhiteSpace(settings.Website) ? "AMIGADB.NET" : settings.Website);
+
+        log("Resolving preview look...");
+        string baseFilter = await ResolveBaseFilterAsync(tools, settings, log, token);
+        bool includeText = !string.IsNullOrWhiteSpace(settings.FontFile) && File.Exists(settings.FontFile);
+
+        string openingPath = Path.Combine(outputDirectory, "opening.png");
+        string closingPath = Path.Combine(outputDirectory, "closing.png");
+        await RenderPreviewStillAsync(
+            tools, settings, baseFilter, includeText,
+            hookFile, titleFile, metaFile, websiteFile,
+            ShortPreviewShot.Opening, openingPath, log, token);
+        await RenderPreviewStillAsync(
+            tools, settings, baseFilter, includeText,
+            hookFile, titleFile, metaFile, websiteFile,
+            ShortPreviewShot.Closing, closingPath, log, token);
+
+        return new ShortPreviewFrames(openingPath, closingPath);
+    }
+
+    /// <summary>Writes one source frame (no style filters) so the crop editor can show the raw clip.</summary>
+    public async Task ExtractSourceFrameAsync(
+        string inputFile,
+        string start,
+        string ffmpegPath,
+        string ffprobePath,
+        string outputPath,
+        Action<string> log,
+        CancellationToken token)
+    {
+        if (string.IsNullOrWhiteSpace(inputFile) || !File.Exists(inputFile))
+            throw new FileNotFoundException("Select a valid source video for the Short.");
+
+        string? directory = Path.GetDirectoryName(Path.GetFullPath(outputPath));
+        if (!string.IsNullOrEmpty(directory))
+            Directory.CreateDirectory(directory);
+
+        ToolPaths tools = await ToolExtractor.ResolveAsync(ffmpegPath, ffprobePath, token);
+        await _runner.RunAsync(tools.Ffmpeg, BuildExtractFrameArguments(inputFile, start, outputPath), log, null, token);
+    }
+
+    internal static List<string> BuildExtractFrameArguments(string inputFile, string start, string outputPath) =>
+    [
+        "-hide_banner",
+        "-y",
+        "-ss",
+        string.IsNullOrWhiteSpace(start) ? "00:00:00" : start,
+        "-i",
+        inputFile,
+        "-frames:v",
+        "1",
+        "-update",
+        "1",
+        outputPath,
+    ];
+
     /// <summary>Looks for a common bold system font to pre-fill the Shorts font field with.</summary>
     public static string? FindDefaultFont()
     {
@@ -122,16 +190,21 @@ public sealed class ShortsPipeline
 
     internal static void Validate(ShortSettings s)
     {
-        if (string.IsNullOrWhiteSpace(s.InputFile) || !File.Exists(s.InputFile))
+        ValidatePreview(s);
-            throw new FileNotFoundException("Select a valid source video for the Short.");
         if (string.IsNullOrWhiteSpace(s.Title))
             throw new ArgumentException("Enter a title.");
         if (string.IsNullOrWhiteSpace(s.OutputPath))
             throw new ArgumentException("Select an output file.");
-        if (s.DurationSeconds <= 0)
-            throw new ArgumentException("Duration must be greater than zero.");
         if (string.IsNullOrWhiteSpace(s.FontFile) || !File.Exists(s.FontFile))
             throw new FileNotFoundException("Select a bold TrueType/OpenType font file.");
+    }
+
+    internal static void ValidatePreview(ShortSettings s)
+    {
+        if (string.IsNullOrWhiteSpace(s.InputFile) || !File.Exists(s.InputFile))
+            throw new FileNotFoundException("Select a valid source video for the Short.");
+        if (s.DurationSeconds <= 0)
+            throw new ArgumentException("Duration must be greater than zero.");
         if (s.Style == ShortStyle.Brand && (string.IsNullOrWhiteSpace(s.BackgroundImage) || !File.Exists(s.BackgroundImage)))
             throw new FileNotFoundException("The brand style requires a background image.");
         if (s.Style == ShortStyle.Video && (string.IsNullOrWhiteSpace(s.BackgroundVideo) || !File.Exists(s.BackgroundVideo)))
@@ -169,8 +242,11 @@ public sealed class ShortsPipeline
 
     internal static string BuildFilterComplex(
         string baseFilter, string fontEsc, string hookEsc, string titleEsc, string metaEsc, string websiteEsc,
-        double hookEnd, double infoStart, double ctaStart)
+        double hookEnd, double infoStart, double ctaStart, bool includeTextOverlays = true)
     {
+        if (!includeTextOverlays)
+            return baseFilter + ";[base]fps=50,format=yuv420p[vout]";
+
         string hookEndStr = F(hookEnd);
         string infoStartStr = F(infoStart);
         string ctaStartStr = F(ctaStart);
@@ -186,8 +262,94 @@ public sealed class ShortsPipeline
             "fps=50,format=yuv420p[vout]";
     }
 
+    internal static List<string> BuildInputArguments(ShortSettings settings, double clipDuration, string? seek = null)
+    {
+        List<string> args =
+        [
+            "-hide_banner",
+            "-y",
+            "-ss",
+            seek ?? settings.Start,
+            "-t",
+            F(clipDuration),
+            "-i",
+            settings.InputFile,
+        ];
+        if (settings.Style == ShortStyle.Brand)
+            args.AddRange(["-loop", "1", "-i", settings.BackgroundImage]);
+        if (settings.Style == ShortStyle.Video)
+            args.AddRange(["-stream_loop", "-1", "-i", settings.BackgroundVideo]);
+        return args;
+    }
+
+    internal static (double HookEnd, double InfoStart, double CtaStart) PreviewOverlayWindows(ShortPreviewShot shot, double duration)
+    {
+        if (shot == ShortPreviewShot.Opening)
+            return (Math.Max(duration, 1), duration + 1, duration + 1);
+
+        return (-1, 0, 0);
+    }
+
+    internal static double PreviewSeekSeconds(ShortPreviewShot shot, double duration)
+    {
+        if (shot == ShortPreviewShot.Opening)
+            return Math.Min(1.2, Math.Max(0, duration * 0.2));
+
+        return Math.Max(0, duration - 0.4);
+    }
+
+    internal static string AddTimestampOffset(string start, double seconds)
+    {
+        if (!TimeSpan.TryParse(start, CultureInfo.InvariantCulture, out TimeSpan parsed))
+            parsed = TimeSpan.Zero;
+        if (seconds < 0)
+            seconds = 0;
+        return (parsed + TimeSpan.FromSeconds(seconds)).ToString(@"hh\:mm\:ss\.fff", CultureInfo.InvariantCulture);
+    }
+
     private static string F(double value) => value.ToString("0.###", CultureInfo.InvariantCulture);
 
+    private async Task RenderPreviewStillAsync(
+        ToolPaths tools,
+        ShortSettings settings,
+        string baseFilter,
+        bool includeText,
+        string hookFile,
+        string titleFile,
+        string metaFile,
+        string websiteFile,
+        ShortPreviewShot shot,
+        string outputPath,
+        Action<string> log,
+        CancellationToken token)
+    {
+        (double hookEnd, double infoStart, double ctaStart) = PreviewOverlayWindows(shot, settings.DurationSeconds);
+        string filterComplex = BuildFilterComplex(
+            baseFilter,
+            fontEsc: includeText ? EscapeFfmpegPath(settings.FontFile) : "",
+            hookEsc: EscapeFfmpegPath(hookFile),
+            titleEsc: EscapeFfmpegPath(titleFile),
+            metaEsc: EscapeFfmpegPath(metaFile),
+            websiteEsc: EscapeFfmpegPath(websiteFile),
+            hookEnd,
+            infoStart,
+            ctaStart,
+            includeTextOverlays: includeText);
+
+        string seek = AddTimestampOffset(settings.Start, PreviewSeekSeconds(shot, settings.DurationSeconds));
+        List<string> args = BuildInputArguments(settings, 0.12, seek);
+        args.AddRange([
+            "-filter_complex", filterComplex,
+            "-map", "[vout]",
+            "-frames:v", "1",
+            "-update", "1",
+            outputPath,
+        ]);
+
+        log($"Preview {shot.ToString().ToLowerInvariant()} frame...");
+        await _runner.RunAsync(tools.Ffmpeg, args, log, null, token);
+    }
+
     internal static string ApplySourceFade(string baseFilter, double fadeInSeconds)
     {
         if (fadeInSeconds <= 0)