Merge Videos – Join Clips into One Video
Merge videos into one file in the order you choose. Drop two or more clips, drag them into place, add a crossfade if you like, and ProMedia joins them on your device. Clips from the same camera with the same settings are joined without re-encoding, so the result is lossless and ready in seconds. Nothing is uploaded and no watermark is added.
- Runs on your device
- WebCodecs · GPU
- FFmpeg
- Works offline
Updated
Drop your videos here
How to merge videos into one
Step 1: Drop two or more videos on the box above (phone clips, screen recordings and camera files can be mixed).
Step 2: Drag the clips into the order you want them to play.
Step 3: Choose a Transition: None, Crossfade or Fade to black. Pick how clips of a different shape should fit under Different shapes.
Step 4: Press Merge and download the combined video.
Good to know
Settings explained
- Different shapes
- How clips with a different aspect ratio are placed in the frame.
- Quality
- Only used when a stream has to be re-encoded. Compatible streams are copied with no quality loss.
- Faster: Smaller file, quickest export
- Balanced: Good quality at a sensible size
- Best quality: Largest file, slowest export
Formats
Combines 2 or more files into one result.
How it runs
- Hardware video engine
- Video is decoded and encoded by your device’s media hardware through WebCodecs — usually several times faster than real time.
- FFmpeg (when needed)
- Older formats and a few filters use FFmpeg compiled to WebAssembly. It downloads once (about 31 MB) the first time it is needed and is cached for offline use.
Lossless join or re-encode: what decides it
ProMedia tries the lossless join first and only re-encodes when something has to change. The join stays lossless when every clip shares the same stream format and you ask for nothing that alters the picture.
| Situation | Result | Why |
|---|---|---|
| Same camera, same settings, Transition: None | Lossless packet copy in seconds | The frames are copied one after another with new timestamps |
| Any transition (crossfade or fade to black) | One re-encode | Transition frames are new pictures that must be drawn |
| Different resolutions, codecs or frame rates | One re-encode | Clips are scaled into one frame; the frame rate is the highest of the clips, up to 60 fps |
| Output size set to 1080p or 720p | One re-encode | Every clip is resized |
| Older formats such as AVI or WMV | Converted once with FFmpeg, then joined | The browser cannot decode them directly |
How do you merge videos without losing quality?
Join clips that match: the same camera or app, the same resolution and frame rate, and Transition left on None. ProMedia checks the codec, the encoder settings, the audio format and the rotation of every clip. If they agree, the compressed frames are copied straight into one file, so the picture is identical to the originals and the merge takes about as long as copying them.
GoPro and many dashcams save one long recording as a series of chapter files. Those chapters normally share identical settings, so dropping them here in order usually rebuilds the full recording without re-encoding.
When clips differ, a re-encode is unavoidable. The Quality setting under Advanced settings decides how much bitrate it gets; Best keeps the most detail at the cost of a bigger file.
Joining clips of different shapes and sizes
A vertical phone clip and a landscape camera clip cannot fill the same frame, so the Different shapes option decides what happens to the space left over. The output frame comes from Output size: the first clip (default), the largest clip, or a fixed 1080p or 720p.
| Option | What you see | Use it when |
|---|---|---|
| Blurred bars (default) | The whole clip over a soft, blurred copy of itself | Mixing portrait and landscape footage for social posts |
| Black bars | The whole clip with black borders | Presentations, archives, anything that should look neutral |
| Crop to fill | The clip zoomed until the frame is full; edges are cut | Shots with the subject in the centre |
Merge videos on iPhone, Android, Windows or Mac
The video merger works in any modern browser. The built-in apps can also combine clips, but they always render a new video, so they are the slower route for footage that could be joined losslessly.
iPhone and iPad
The Photos app cannot join clips; iMovie can, by placing them on one timeline and exporting. In Safari here, pick the clips from Photo Library, set the order and save the merged file to Files or Photos.
Android
Google Photos can build a movie from several clips in its editor. For a straight, lossless join of camera clips, open this page in Chrome and pick them from your gallery.
Windows
Clipchamp, included with Windows 11, merges clips on its timeline and exports a new file. Drag MP4 files from File Explorer into Chrome or Edge here when you want the original quality kept.
Mac
QuickTime Player has Edit → Add Clip to End for two or three files. For many clips, mixed formats or crossfades, drop them into Safari or Chrome here.
Tips & troubleshooting
Cut each clip to the part you need with the video trimmer before joining. Clips cut with Instant mode can carry hidden lead-in frames, in which case the join is re-encoded once.
Want one music track under the whole video? Merge first, then add music to the video so the song runs across the cuts.
Joining photos rather than clips? The slideshow maker turns pictures into a video with transitions and music.
A merged video too big to send? Shrink it to an exact size with the video compressor.
Joining audio files only? The audio joiner combines audio files such as MP3, M4A and WAV.
Merge Videos FAQ
How do I combine videos into one video?
Drop the clips on this page, drag them into order and press Merge. Matching clips are copied into one file without re-encoding; clips that differ are scaled into one frame and encoded once.
How do I merge 3 or more videos together?
Add them all at once. There is no fixed limit on the number of clips: drag them into order on the list and press Merge. Each clip plays in full, one after the other, with the transition you picked between them.
Can I merge videos online for free without a watermark?
Yes. Merging is free, needs no account and adds no watermark or intro. The clips are joined in your browser, so nothing is uploaded and there is no queue.
Why was my merge re-encoded?
At least one clip differed in codec, resolution, encoder settings, audio format or rotation, or you chose a transition or a fixed output size. Any of these means new frames have to be drawn. The result card shows whether the video was copied or re-encoded.
Can I merge long videos?
Yes. Clips are read and joined in a stream, never held in memory whole, so long recordings work on a computer. A lossless join of hour-long files takes about as long as copying them.
Is there a file size limit?
There is no upload limit because there is no upload. Videos are read in chunks straight from disk, so multi-gigabyte files work on desktop computers; phones are limited by their memory. There are no daily caps and no watermark.