Merge Videos with FFmpeg
Create FFmpeg concat commands for joining video files, with copy and re-encode options.
FFmpeg.Run generates commands only. Your media files stay on your computer and are never uploaded.
Command options
Generated command
Common uses
- Join clips from the same camera
- Merge MP4 files without re-encoding
- Fallback to re-encoding when clips do not match
Related articles
- How to Merge Videos with FFmpeg
Merge MP4 and other video files with FFmpeg. Learn the fast lossless concat method, the re-encoding filter method, and how to fix common merge errors.
Related command recipes
Command notes
The concat demuxer reads file names from `files.txt` and joins them in order.
Stream copy is fast and lossless, but it works best when inputs share the same technical properties.
Re-encoding is slower, but it can fix many compatibility issues between mismatched clips.
FAQ
When can I merge without re-encoding?
Use stream copy when the clips have matching codecs, resolution, frame rate, time base, and audio layout.
Why does concat sometimes fail?
Concat fails when source files differ too much. Re-encoding is slower but more tolerant.
Do I need a files.txt list?
The concat demuxer uses a text file that lists input clips in order. This tool generates both the list content and the FFmpeg command.