Fusion de videos
Fusionnez plusieurs videos en un seul fichier.
Drop video files here to merge
or click to browse · select multiple files · max 500 MB total
FFmpeg WASM (~25MB) will be downloaded on first use and cached by your browser.
Video Merger
Merge multiple video files into a single MP4 file directly in your browser. Uses FFmpeg concat demuxer for seamless joining. All processing happens locally - no upload needed.
À quoi ça sert ?
- Combining multiple video clips into one continuous video
- Joining footage from different cameras or recording sessions
- Creating compilations and highlight reels
- Assembling video presentations from separate segments
Guide étape par étape
- Click upload or drag and drop multiple video files
- Reorder files using the up/down arrows
- Click 'Merge' to combine all files
- Preview the merged result
- Download the combined MP4 file
Comment ça marche
FFmpeg's concat demuxer joins video files sequentially. For best results, use files with the same codec, resolution, and frame rate. The output is re-encoded as H.264/AAC MP4 for maximum compatibility.
Conseils et bonnes pratiques
- For seamless merging, use files with matching resolution and frame rate
- Total file size is limited to 500MB
- Files are merged in the order shown - use the arrows to reorder
Video Format Compatibility for Merging
| Feature | MP4 (H.264) | WebM (VP9) | MKV |
|---|---|---|---|
| Browser Support | Universal | Chrome, Firefox, Edge | Limited (needs plugins) |
| Compression | Excellent | Very Good | Depends on codec |
| Quality | High at low bitrates | High, especially at low bitrates | Lossless capable |
| Merge Speed | Fast | Moderate | Fast (stream copy) |
| Best For | Social media, web playback | Web-optimized streaming | Archival, multi-track |
Questions fréquentes
Can I merge videos with different resolutions?
Yes, but the output will be re-encoded to match a consistent resolution. For best results, use videos with the same resolution (e.g., all 1920x1080). When resolutions differ, FFmpeg scales all clips to match, which may introduce letterboxing or slight quality loss. Converting all clips to the same resolution before merging ensures the cleanest output.
What happens to the audio when merging videos?
Audio tracks from each video are preserved and concatenated sequentially. The audio is re-encoded as AAC in the merged MP4 output. If some clips have audio and others don't, silent gaps will appear where audio is missing. For the best results, ensure all clips have audio tracks with matching sample rates.
Why is my merged video file larger than expected?
The merged file is re-encoded to H.264/AAC for maximum compatibility, and the encoding settings may differ from the originals. If your source videos used aggressive compression, the re-encoded output might be slightly larger. You can reduce file size by lowering the output resolution or bitrate. The total size also depends on the combined duration of all input clips.
What's the maximum number of videos I can merge?
There is no hard limit on the number of video files. However, the total combined file size must stay under 500MB since all processing happens in your browser's memory. For large projects, consider merging in batches - combine a few clips at a time, then merge the intermediate results together.
Do I need matching codecs for all input files?
No, you can merge videos with different codecs (e.g., H.264, H.265, VP9). The tool re-encodes all input streams to a common format (H.264 video + AAC audio) during the merge process. While this ensures compatibility, matching codecs and parameters across input files will produce faster processing and more predictable results.
Confidentialité & Sécurité
Cet outil utilise FFmpeg compilé en WebAssembly (WASM). Le binaire WASM (~25 Mo) est téléchargé depuis un CDN lors de la première utilisation et mis en cache par votre navigateur. Tout le traitement des fichiers se fait localement sur votre appareil - vos fichiers ne sont jamais envoyés à un serveur. Cela le rend sûr pour les fichiers multimédias sensibles, privés ou confidentiels. Les fichiers volumineux peuvent prendre plus de temps à traiter en fonction du processeur et de la mémoire disponible de votre appareil.