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Drop in your clips, drag them into order and get one continuous video. When the clips come from the same camera they are joined without re-encoding; when they don't, the merger converts them to a common size, frame rate and audio format so the result plays cleanly.
Processing locally on your device
Overview
Joining videos sounds simple, but clips only stitch together cleanly when they match. As soon as you add files, the merger reads each one with FFmpeg and lists its length, resolution, codec, frame rate, audio format and file size. If every clip shares the same video codec, resolution and frame rate, and the same audio codec, sample rate and channel layout, a fast join is available. Clips from the same phone or camera, or parts made by a splitter, almost always qualify.
A fast join uses FFmpeg's concat demuxer to copy the compressed streams one after another, so it takes seconds and the quality is identical to the originals. If all the clips share an extension, the output keeps it (MP4, MOV, WebM or MKV); otherwise it is saved as MP4. Where the clips differ — a phone video and a screen recording, or 30 and 60 fps footage — the fast option is disabled and the merger re-encodes instead.
Re-encoding brings every clip to one shape before joining. You choose the output resolution (the first clip's size, 1080p or 720p landscape, 1080×1920 or 720×1280 vertical, or 1080×1080 square), a frame rate of 24, 25, 30 or 60 fps, and an audio sample rate of 44.1 or 48 kHz. Clips with a different shape are scaled to fit and letterboxed with black bars, never stretched. Clips without sound get matching silence, so audio and picture stay in sync across the join. The result is an H.264 MP4 with stereo AAC audio at 160 kbps.
Everything runs in your browser with FFmpeg 5.1 compiled to WebAssembly, downloaded once (about 31 MB) and cached. Your clips are read straight from disk rather than copied into memory. Re-encoding is the slow part: expect anything from roughly real time to several times slower for 1080p footage, depending on your computer, so keep the tab open on longer jobs.
| Fast join | Re-encode | |
|---|---|---|
| Requirement | Clips match exactly | Any clips |
| Speed | Seconds | Roughly real time or slower |
| Quality | Lossless | High (H.264 CRF 21) |
| Output | Original container | MP4 |
| Mixed sizes | Not possible | Letterboxed to one size |
Drop two or more video clips onto the merger.
Drag the rows, or use the up and down arrows, to set the order; remove any you don't need.
Use Fast join if it's available, or pick Re-encode.
For a re-encode, choose the resolution, frame rate and audio sample rate.
Click Merge and download the combined video.
Use cases
Action cameras and dashcams split long recordings into separate files. They match exactly, so the fast join puts them back together losslessly in seconds.
Combine short clips from a day out into one video for a family chat. If they came from different phones, re-encode to 1080p at 30 fps so they play smoothly as one.
Collect several short clips into a single 1080×1920 video for Reels, Shorts or TikTok. Landscape clips are letterboxed rather than squashed.
Put a branded intro before a recording and an end card after it, so every upload starts and finishes the same way.
Pro tips
Answers to common questions about the video merger.
A lossless join only works when every clip has the same video codec, resolution and frame rate, and the same audio codec, sample rate and channel layout. If anything differs, the merger converts all clips to one format with Re-encode.
A fast join copies the original data, so there is no loss. A re-encode creates a new H.264 file at a high quality setting (CRF 21), which is hard to tell apart from the source at normal viewing sizes.
In a re-encode every clip is scaled to fit the chosen resolution and centred with black bars where needed. Nothing is cropped or stretched.
No. When re-encoding, the merger fills that clip's duration with silence, so the audio of the following clips stays in sync with the picture.
A fast join usually takes a few seconds regardless of length. A re-encode processes every frame in your browser, so a few minutes of 1080p video can take several minutes on an average laptop.
No. ToolEnhancer processes files on your own device inside the browser. They are never sent to, stored on or seen by our servers.
Yes. The video merger is free to use with no sign-up, no watermarks and no daily limits.