Video Merger

About this tool

Joins two or more video clips into a single video, in the order you arrange them — even if the clips are different formats, resolutions, or aspect ratios. Runs entirely in your browser using ffmpeg.wasm, a WebAssembly build of the real ffmpeg; your videos are never uploaded anywhere.

The ffmpeg engine (about 32MB) is only downloaded the first time you use this tool, not when the page loads. Because clips can differ in format and resolution, every clip is re-encoded to match the chosen output resolution — there's no lossless "just stick them together" shortcut when inputs don't already match.

Frequently asked questions

Can I change the order after selecting files?

Yes — use the up/down arrows next to each clip in the list to reorder them before merging.

What happens if a clip has no audio?

Merging currently expects every clip to have its own audio track — a completely silent/audio-less clip may cause the merge to fail. If that happens, try re-exporting that clip with a silent audio track added first.

Why does processing take a while?

Every clip is fully re-encoded (not just copied) so they can be joined regardless of their original format — this runs single-threaded WebAssembly with no hardware acceleration, so expect processing time comparable to the combined length of all your clips.

Is my video uploaded anywhere?

No — the entire process, including the ffmpeg engine itself, runs locally in your browser via WebAssembly. Nothing is sent to any server.