Moonsplice

Movie Slicer & Joiner
Free • Open Source • MIT Licensed

Features

Video Splicing

• Frame-accurate editing - Step through video frame-by-frame for precise cuts
• Visual timeline with range selection and playback scrubbing
• Thumbnail previews for each segment
• Drag-and-drop video loading
• Multiple segments - Create unlimited video segments from a single source
• Reorderable segments - Move segments up/down to arrange final output
• Variable playback speed - 0.25× to 2.0× speed control
• Keyboard shortcuts - Efficient editing workflow

Video Joining

• Multi-file concatenation - Join multiple videos into one
• Per-file trimming - Trim each video individually before joining
• Three transition modes:
  • None - Instant cuts (lossless, fastest)
  • Fade to Black - Smooth fade transitions between clips
  • Crossfade - Blend clips together for seamless transitions
• Customizable transition duration - Adjust fade/crossfade timing (100-5000ms)
• Visual previews - See thumbnails of each video segment
• Drag-and-drop support - Add multiple files at once

Professional Output

• Built on FFmpeg for industry-standard video processing
• Lossless output option for instant cuts (no re-encoding)
• High-quality re-encoding with H.264 for transitions
• Maintains original video quality and audio

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Installation

Requirements

• Windows 10/11 (64-bit)
• .NET 8.0 Runtime - Download here
• FFmpeg - Included in release, or download separately

Quick Start

1. Download the latest release from Releases
2. Extract the ZIP file
3. Run Moonsplice.exe
4. Drag and drop a video file to begin editing

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User Guide

Splicing Videos

1. Load a Video

• Drag and drop a video file onto the window, OR
• Click the placeholder area and browse for a file

2. Set Segment Range

• Use the timeline slider to preview your video
• The left thumb (green) sets the start point
• The right thumb (green) sets the end point
• The yellow marker shows current playback position
• Drag any thumb to preview that position in the video

3. Frame-Perfect Editing

• Use Left/Right arrow keys to step through frame-by-frame
• Use , and . to jump back/forward 5 seconds
• Use K and L to jump back/forward 15 seconds
• Adjust playback speed with the speed controls (0.25× - 2.0×)

4. Add Segments

• Click Add Segment (or press Enter) to save the current range
• Segments appear in the left panel with thumbnail previews
• Add as many segments as needed

5. Manage Segments

• Play - Preview a specific segment
• Move Up/Down - Reorder segments for final output
• Delete - Remove unwanted segments

6. Export

• Click Export to render your final video
• Choose output location and filename
• Select transition mode in Settings (None/Fade to Black/Crossfade)

Joining Videos

1. Switch to Join Tab

• Click Join in the top navigation bar

2. Add Videos

• Drag and drop multiple video files onto the window, OR
• Click Add Files to browse

3. Trim Individual Videos (Optional)

• Each video has its own range slider
• Drag the handles to trim start/end of each clip
• Trim range shows in real-time

4. Reorder Clips

• Use Move Up/Down buttons to arrange video order
• Final output will play videos in the order shown

5. Export

• Click Join & Export
• Choose transition mode in Settings:
  • None - Instant cuts (lossless, fast)
  • Fade to Black - Configurable fade transitions
  • Crossfade - Smooth blending between clips

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Keyboard Shortcuts

Action	Default Key	Customizable
Set Segment Start	[	✅
Set Segment End	]	✅
Jump Back 5s	,	✅
Jump Forward 5s	.	✅
Jump Back 15s	K	✅
Jump Forward 15s	L	✅
Add Segment	Enter	✅
Play/Pause	Space	✅
Frame Back	←	❌ (Fixed)
Frame Forward	→	❌ (Fixed)
Volume Up	↑	❌ (Fixed)
Volume Down	↓	❌ (Fixed)

To customize shortcuts:

1. Go to Settings tab
2. Click the key field you want to change
3. Press your desired key
4. Settings auto-save

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Settings

General

• Always on Top - Keep Moonsplice window above other applications

Segment Transitions

Choose how segments are joined together:

• None - Direct cuts with no transition (lossless, instant)
• Fade to Black - Brief fade to black between segments
• Crossfade - Smooth blend between segments

Note: Transitions require re-encoding and take longer to export

Transition Duration

• Customize fade/crossfade duration in milliseconds (100-15000ms)
• Default: 1000ms (1 second)
• Shorter durations = quicker transitions
• Longer durations = smoother, more gradual transitions

FFmpeg Configuration

• FFmpeg Path - Location of ffmpeg.exe (default: included in app folder)
• Browse to use a custom FFmpeg installation if needed

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Tips & Best Practices

For Best Performance

• Use None transition mode for quick exports (no re-encoding)
• Close other applications when exporting large videos
• Ensure sufficient disk space (exports can be large)

For Highest Quality

• Use original, high-quality source videos
• Avoid re-encoding multiple times (quality degrades)
• Use Crossfade sparingly (computationally expensive)

Frame-Accurate Editing

• Use arrow keys to step through frames for precise cuts
• The yellow playback marker is independent of the range thumbs
• Drag range thumbs to preview start/end positions
• Press Play to start from the yellow marker position

Organizing Large Projects

• Name your output files clearly (e.g., ProjectName_v1.mp4)
• Keep source videos in one folder
• Export intermediate versions before making major changes

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Troubleshooting

"FFmpeg not found" Error

Solution:

1. Go to Settings tab
2. Click Browse next to FFmpeg Path
3. Navigate to ffmpeg.exe location
4. Select the file and click OK

Video Won't Load

Possible causes:

• Unsupported format (try MP4, AVI, MKV, MOV)
• Corrupted video file
• Missing codecs

Solution: Convert video to MP4 using a tool like HandBrake first

Export Takes Too Long

Causes:

• Using Fade to Black or Crossfade transitions (requires re-encoding)
• Very large or high-resolution videos

Solutions:

• Use None transition mode for instant exports
• Export smaller sections separately
• Reduce transition duration in Settings
• Upgrade to faster hardware (SSD, more RAM)

Thumbnails Not Generating

Solution:

• Ensure FFmpeg is properly configured
• Check that source video is not corrupted
• Restart Moonsplice

Transitions Happen Immediately (No Fade Effect)

Solution: This was a bug in early versions. Ensure you're using the latest release where transitions start near the end of clips, not at the beginning.

Timeline Thumbs Don't Update Video Preview

Solution: This is expected behavior:

• Dragging range thumbs (green) previews that position without moving the playback marker
• Dragging the yellow marker or using skip buttons moves the actual playback position
• Press Play to start playback from the yellow marker

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Technical Details

Supported Formats

Input: MP4, AVI, MKV, MOV, WMV, FLV, WebM
Output: MP4 (H.264 video, AAC audio)

Video Processing

• Lossless Mode (None transition): Direct stream copy, no quality loss
• Re-encoded Mode (Fade/Crossfade): H.264 codec, CRF 18 (high quality)
• Audio: AAC 192kbps

System Requirements

• OS: Windows 10/11 (64-bit)
• RAM: 4GB minimum, 8GB recommended
• Storage: 500MB for app + space for video files
• CPU: Multi-core processor recommended for faster exports

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Building from Source

Prerequisites

• Visual Studio 2022 or later
• .NET 8.0 SDK
• FFmpeg binaries (ffmpeg.exe and ffprobe.exe)

Dependencies

• TopazWPF - Custom UI framework (referenced as local project)
• .NET 8.0 Windows Desktop Runtime

Build Steps

git clone https://github.com/stephenmthomas/moonsplice.git
cd moonsplice
# Place TopazWPF project in ../../TopazWPF/TopazWPF/ or adjust .csproj reference
dotnet restore
dotnet build -c Release

Project Structure

Moonsplice/
├── MainWindow.xaml          # Main UI layout
├── MainWindow.xaml.cs       # UI logic and event handlers
├── FFmpegWrapper.cs         # FFmpeg integration
├── VideoSegment.cs          # Segment data model
├── AppSettings.cs           # Settings persistence
├── App.xaml                 # Application resources
└── Moonsplice.csproj        # Project configuration

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Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Areas for Contribution

• Additional transition effects
• Video format support improvements
• UI/UX enhancements
• Performance optimizations
• Bug fixes

Guidelines

1. Fork the repository
2. Create a feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

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License

This project is licensed under the MIT License - see the LICENSE file for details.

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Acknowledgments

• FFmpeg - Video processing engine (ffmpeg.org)
• TopazWPF - Custom WPF UI framework
• BandiCut - If they didn't force you to pay to remove a splash screen, this app would not exist.

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Support

• Issues: GitHub Issues
• Discussions: GitHub Discussions

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Changelog

Version 1.0.0 (Initial Release)

• Video splicing with frame-accurate editing
• Multi-file video joining
• Three transition modes (None, Fade to Black, Crossfade)
• Customizable transition duration (100-5000ms)
• Customizable keyboard shortcuts
• Per-file trimming in Join mode
• Thumbnail generation from video frames
• Variable playback speed control (0.25× - 2.0×)
• Independent timeline controls (range thumbs + playback marker)
• Dark theme UI with modern design
• Settings persistence across sessions

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Made with 🩸💧😭 for video editors everywhere