File picking and downloads often fail inside apps. Open this page in your default browser (Chrome, Safari) or on a computer.
Merge Videos
Pick MP4, AVI or MOV clips, set the order and get one video. Clips that share a format, such as several recordings from the same phone, are joined without re-encoding, so quality is unchanged and it only takes seconds. Nothing is uploaded: the work happens in your browser, so there's no upload wait and your videos stay on your device.
Choose two or more videos and press Merge.
How to merge videos
- Press Choose video files. The first time, the video engine (ffmpeg, about 32 MB) downloads, so Wi-Fi is a good idea.
- Set the order with ↑ and ↓. The top clip plays first. Each file shows its length, resolution and codec.
- Press Merge videos, play the result on the page, then Download it.
The note under the list tells you in advance whether the clips will be joined as-is or re-encoded. The start times under the result work as YouTube chapters.
Lossless joining vs. re-encoding
A video file is a container (MP4, AVI and so on) holding compressed video and audio. When the codec (such as H.264), resolution, frame rate and audio format all match, the compressed data can be joined without decoding it, so there is no quality loss and it takes seconds. Clips from the same phone, dashcam or action camera with the same settings usually qualify.
| Your clips | Method | Quality and speed |
|---|---|---|
| Codec, resolution, frame rate and audio all match | Joined as-is | Identical to the originals, seconds |
| Anything differs (other devices, portrait and landscape mixed) | Scaled to one size and re-encoded to H.264 MP4 | Slow – can take longer than the video itself |
When re-encoding, the size follows the first clip's shape and other shapes get black bars instead of being cropped. Encoding inside a browser is much slower than desktop software, so 720p is the recommended setting.
Good uses
- Dashcams and action cameras save 1–3 minute chunks. Join the clips around an incident into one file for an insurer or the police.
- Phone videos: stitch the short clips of a birthday or a trip into one video to share with family.
- Lecture and screen recordings that were recorded in several parts.
Dashcam footage and family videos are not things you want to hand to a stranger's server. This tool never uploads them.
Things to know
- File size: the merged video is built in your device's memory. Keep the total under 1–2 GB on a computer and a few hundred MB on a phone.
- Re-encoding is slow: it runs as software inside the browser. A 10-minute video can take tens of minutes on a computer, so for long clips record with the same settings or use desktop editing software.
- Even when clips look identical, slightly different encoder settings can garble the picture after a join. If that happens, choose Always re-encode.
- AVI results can't be previewed in the browser; download and open them in a video player. Subtitles and chapters are not carried over.
FAQ
Are my videos uploaded?
No. Videos are never sent to a server; they are processed in your browser. The only download is the video engine (ffmpeg.wasm) from a public CDN, once, after which your browser cache serves it.
Can I mix MP4 and AVI?
Yes. Different formats are re-encoded into one MP4. If every clip is an AVI with the same format, the result is an AVI; otherwise it's an MP4.
Do iPhone (HEVC) videos work?
Yes. Clips from the same iPhone with the same settings are joined as HEVC without re-encoding. Some Windows PCs and browsers can't play HEVC, so the preview may stay blank even though the file is fine.
Sources
- FFmpeg compiled to WebAssembly, runs in the browser: ffmpeg.wasm (GitHub)
- Options and filters reference: FFmpeg documentation
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