What video formats can I merge?

You can merge MP4, MKV, MOV, AVI, WebM and most common formats. For best results with stream copy mode, use files with the same codec. Use re-encode mode for mixed formats.

What is the difference between stream copy and re-encode?

Stream copy is fast and lossless — it joins clips without re-encoding, but requires all files to share the same codec. Re-encode mode works with any mix of formats and codecs, but is slower as it re-encodes everything to H.264 MP4.

Is my video uploaded to a server?

No. All merging is done inside your browser using FFmpeg.wasm. Your files never leave your device.

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🔗 Video Merger

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Add Video Files

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Drop video files here

or tap / click to browse — MP4, MKV, MOV, AVI, WebM supported

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Clips to Merge

No video files added yet. Drop files above or tap / click to browse.

MERGE MODE

Use Stream Copy if all clips are the same format. Switch to Re-encode if you get errors.

Ready.

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About This Tool

This tool uses FFmpeg.wasm to join video clips inside your browser. Stream Copy mode is fast and lossless — ideal when all clips share the same codec. Re-encode mode is universal — it re-encodes everything to H.264 MP4, handling mixed formats at the cost of processing time.

🎬 MP4 · MKV · MOV · WebM

↕ Reorder before merging

✓ Zero server transmission

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Frequently Asked Questions

Are my videos uploaded to a server?

No. All merging is done using FFmpeg.wasm which runs entirely in your browser. Your video files never leave your device and are never transmitted to any server.

Do videos need to be the same format?

For stream copy mode (fastest, no quality loss), videos should share the same codec and format. If they differ, the tool can re-encode them to a common format, which allows merging any combination of input formats.

What is the output format?

The merged output is saved as an MP4 file, which offers the best compatibility across devices, media players, and platforms.