How-to
Merge video clips into one file, with no watermark
Several takes from the same shoot, a handful of screen recordings for one tutorial, clips from two different phones for the same event: the video merger joins them into a single file in your browser, in the order you choose, with no watermark stamped over the result and no upload of the footage.
Step by step
- Open the video merger and drop in at least two clips (MP4, MOV, AVI, MKV, WebM, MPEG and 3GP all work). Drag an item in the queue to a new position, or use the up/down buttons, to set the order they will play in.
- Leave the strategy on "auto": it re-encodes every clip to H.264 video and AAC audio in an MP4 container, matching their resolution and frame rate along the way so clips from different sources join cleanly. Only switch to "copy" if every clip already comes from the exact same camera and export settings; it skips the re-encode entirely for a much faster, lossless join.
- Run the merge and download the combined file. Nothing is added over the footage and no login or watermark is involved at any point.
Why "auto" re-encodes instead of just joining the files
The fastest way to join two video files is to stitch their compressed data together without decoding it at all, and the tool can do exactly that in "copy" mode. The catch is that this only produces a playable result when every clip shares the same codec, resolution, frame rate and pixel format; two MP4 files can look identical by their file extension and still fail that test, which would silently produce a broken or garbled file. "Auto" re-encodes every clip instead, which costs a little processing time but works regardless of where the clips came from.
How clips of different sizes are matched up
Before joining, each clip is scaled to fit inside a common frame size, based on the first clip's resolution (or 1280x720 at 30 frames per second when that cannot be read), and padded on the sides or top and bottom to fill any leftover space evenly. This keeps every clip at its original aspect ratio rather than stretching it, and gives every clip the same dimensions and frame rate before the join, which is what keeps the merged result clean instead of glitching partway through where the sources changed.
When to force the "copy" strategy instead
If every clip was exported from the same app or camera with identical settings, forcing "copy" joins them in a couple of seconds with zero quality loss, since none of the video or audio data is touched. It is worth trying first for same-source footage and falling back to "auto" if the result does not play correctly. For anything mixed, different phones, different apps, a screen recording alongside a camera clip, "auto" is the strategy that reliably works.
The tools used in this guide
- Merge video filesConcatenate multiple video files (MP4, MOV, WebM…) into one. Fast copy or re-encode. No upload.
- Trim videoCut a video to a start/end time range directly in your browser. Fast stream copy or precise re-encode. No upload.
- Compress videoReduce video file size via in-browser H.264 re-encode. No upload, no server.
- Merge audio filesConcatenate multiple audio files (MP3, WAV, M4A, OGG…) into one. Drag to reorder. No upload.
Frequently asked questions
Does merging add a watermark or shrink my video's resolution?
No watermark is added at any point. If your clips share the same resolution, the merged file keeps it. If they differ, the "auto" strategy scales and pads each clip to a common frame size so the join works cleanly, which can mean a clip is fit inside letterboxing rather than stretched to fill the frame; forcing "copy" on identical clips avoids any re-encoding step entirely.
Can I merge clips recorded on different phones at different resolutions?
Yes, that is what the "auto" strategy is for. It re-encodes every clip and matches their resolution and frame rate to a common target before joining them, so mismatched sources merge into one clean file. It takes longer than the lossless "copy" path, since every clip is decoded and re-encoded, but it works across mixed cameras and apps.