Merge_Video

Imported from PhamXuanCong/Merge_Video (AGENTS.md). Install upstream with npx skills add PhamXuanCong/Merge_Video. Copyright stays with the author.

VideoMergeTool instructions

Product

VideoMergeTool is a Windows WPF application.

The user selects one input folder containing MP4 videos.

The application:

1. Scans MP4 files recursively.
2. Excludes output and processed folders.
3. Selects a bundled companion video from Assets/CompanionVideos.
4. Combines the input and companion videos horizontally.
5. Writes results into /output.
6. Preserves the input folder's relative structure.

Architecture

• App contains WPF UI and ViewModels.
• Core contains models, enums, interfaces and business rules.
• Infrastructure contains filesystem, FFmpeg and FFprobe implementations.

Core must not reference App or Infrastructure. Infrastructure must not reference App.

Do not put FFmpeg commands or filesystem code in ViewModels.

Safety

Never delete or move an input video unless:

• FFmpeg exited successfully.
• The temporary output exists.
• FFprobe validates the output.
• The output contains a video stream.
• The output duration is within one second of the input duration.
• The temporary output was committed to its final filename.

On cancellation or failure:

• Preserve the input video.
• Delete the temporary .processing.mp4 file.

Never modify files under Assets/CompanionVideos.

Runtime paths

Resolve bundled files from AppContext.BaseDirectory.

Expected paths:

• Tools/ffmpeg.exe
• Tools/ffprobe.exe
• Assets/CompanionVideos

Code conventions

• Use constructor injection.
• Use CancellationToken for async workflows.
• Use ProcessStartInfo.ArgumentList.
• Do not concatenate quoted process arguments.
• Use invariant culture for FFmpeg numeric arguments.
• Keep parsing logic unit-testable.
• Run build and relevant tests before completing a task.