# Merge Videos

> Merge videos online in your browser: join MP4, MOV, WebM, MKV or dashcam .ts clips into one file in seconds, without re-encoding. Quality unchanged, no upload.

- URL: https://bytescope.dev/en/merge-videos/
- Locale: en · Also: [ja](https://bytescope.dev/ja/merge-videos.md) · [zh-Hant](https://bytescope.dev/zh-Hant/merge-videos.md)
- Runs: Your files never leave your browser — all processing is local.
- Requires: Any modern browser can merge. Saving straight into a file you choose needs Chrome, Edge or Opera on desktop (File System Access API). Other browsers build the output in memory and stop around 1 GB.
- Updated: 2026-09-08

## What it does

Drop the clips, check the order, and get one video back. The pictures and sound are not decoded or re-encoded: their packets are copied, in order, into a single new file, so joining takes about as long as reading the files and the quality is exactly what you recorded. The files are never uploaded; everything happens in your browser, and on desktop Chromium the result streams straight into a file you choose.

### When you need it

Phones and cameras cut long recordings into pieces on their own. A dashcam saves a new file every one to three minutes, and you want the minutes around an incident as one clip for an insurer or the police. An action camera starts a new file every 4 GB. Some screen recorders and drones do the same. Files are sorted by name the way a person would, so clip2 comes before clip10, and you can move any clip up or down before joining. A table lists each clip's codec, size, orientation and audio format, so you see a mismatch before you start.

### What has to match

Joining without re-encoding only works when the clips were made by the same device with the same settings: same video codec and its parameters, same resolution, same orientation, same audio format. A clip that differs is flagged in red with the reason, and you can remove it and join the rest. Clips from different phones, mixed portrait and landscape clips, or a mix of codecs need re-encoding, which this page does not do yet. A WebM or MKV that carries a rotation flag cannot be joined without re-encoding, because those containers cannot store orientation.

### Honest limits

Each join may have a very short pause or a soft click, about 0.03 seconds, because the audio of every clip starts with a little encoder padding. This is not a transition or a bug. There are no transitions, titles or background music here; that is a video editor's job. Supported inputs are MP4, MOV, WebM, MKV and the .ts files many dashcams write; AVI is not supported. Up to 50 clips per run, and browsers without a save dialog build the result in memory, so a very large total is stopped with a message.

Joined clips keep the first clip's container (a .ts first clip gives an MP4). If the whole thing is sideways, Rotate Video fixes it with the same copy-only method. To keep only a section of one file, use Video Trimmer.

## Limits

Does not re-encode, so clips must share codec, resolution, orientation and audio format (same device, same settings); it does not add transitions, titles or music, and does not read AVI.

## FAQ

### Does merging change the video quality?

No. The video and audio are never decoded or re-encoded; their packets are copied as they are into one file. Resolution, bitrate and codec stay the same, and the joining itself takes seconds even for a large file.

### Why can't my videos be merged?

Because they are not identical in format. Without re-encoding, every clip must share the codec and its parameters, resolution, orientation and audio format, which is normally true only for clips from the same device and settings. The page marks the clip that differs and says which property, such as size, orientation or audio. Clips from different phones, portrait mixed with landscape, or one clip without sound among clips with sound will be stopped. Remove the odd clip, or wait for the re-encoding option.

### Will there be a gap or click where clips meet?

Possibly. The audio of each clip begins with a short stretch of near-silence left by the encoder, about 0.03 seconds, so a join may sound like a tiny pause or a soft click. Picture is unaffected. It cannot be removed without re-encoding the audio.

### Which formats work, and what about dashcam .ts and AVI?

MP4, MOV, WebM, MKV and MPEG-TS (.ts), which many dashcams use. A .ts first clip produces an MP4. AVI is not supported. WebM and MKV clips that carry a rotation flag are refused, because those containers cannot store orientation.

### Can I add transitions, titles or music?

No. This page only joins clips end to end. Transitions, titles and background music need a video editor and re-encoding, which is outside what this tool does.

### Are my videos uploaded?

No. Each file is read from your disk in the browser and the joined video is written back to your disk. There is no server in between, so there is no queue and no upload to wait for.