# Merge Videos: Online Video Merger and Video Combiner

Combine videos into one MP4 in the order you choose, with matched frame size and loudness.

## How it works

1. Add two to twenty MP4, MOV, or WebM clips and drag them into playback order.
2. Press Merge videos to open the editor on Media, where you can reorder clips or turn on Even out loudness.
3. Preview the combined timeline and press Export to download one finished MP4.

## Combining multiple MP4 and MOV clips into one timeline

Audo’s online video merger and video combiner joins two to twenty MP4, MOV, MKV, WebM, or AVI files up to 2 GB into one continuous MP4 without an account, with the first 5 minutes free, 10 times a day, and no sign-up. Whether you are stitching an intro and outro onto an episode, combining multi-part phone clips, or assembling a highlight reel, all clips line up in order on a single browser timeline.

Because different cameras record at different resolutions, frame rates, and microphone levels, Audo conforms every clip to a shared canvas and lets you even out loudness across clips, add auto captions, or resize the frame before exporting one H.264 MP4.

Tool: Join files (`join_audio`). The same tool's other pages: https://audo.ai/audio-joiner.md. Price: 1 credit a minute — $0.01/min ($0.60/hr), with no subscription — of input for whole files, charged only when a job succeeds.

## Free API

```bash
curl -F file=@intro.mp4 -F file=@episode.mp4 https://audo.ai/api/try/join -D response.headers -o response.body
```

Read response.headers and response.body before naming media. Handle 202, 200 JSON and errors with the complete response client at https://audo.ai/docs/api?utm_source=markdown&utm_medium=agent#responses.

Free for the first hour of each file, 10 times a day per person, with no key or account. Uploads up to 10 GB, 2 at once from one address. The response is the result itself; a job that runs longer than about 30 seconds returns 202 with a link to check on it. With an API key (`-H "Authorization: Bearer $AUDO_API_KEY"`), omitting free runs the whole file with credits if the balance covers it, otherwise the free portion if quota remains. Set free=true to prohibit spending; for paid whole files use free=false with an approved positive max_credits. A free result cut short comes with finishUrl (and the Audo-Finish-Url header when the response is the file itself): give it to the person, who pays there (from $5, no sign-up), and the whole file runs; keep checking the status link, whose finishedBy names the whole-file job and its own status link. Details: https://audo.ai/docs/api.md

## Options

Form fields with the same names as the MCP tool's inputs:

- `crossfade_ms`: A crossfade between files, in milliseconds (0 to 5000), such as 500. Default 0.
- `video_mode`: For video inputs: fit pads, fill crops to the first video’s frame. Default fit.
- `match_loudness`: Matches the files' loudness before joining. Default true.
- `output_format`: The result's format: same (as the first file), wav, mp3, m4a, or flac. Default same.

## Languages

Any language: it works on the sound, not the words.

## From an assistant (MCP)

Add https://audo.ai/mcp and sign in (setup for each assistant: https://audo.ai/setup.md). The tool is `join_audio`:

> Joins 2 to 20 files in order into one, such as an intro, an episode, and an outro. Use it when the person wants recordings combined. It costs 1 credit a minute of the combined length, charged only if the job succeeds. Returns the result with download links, or job_id for get_job if it takes longer.

Example: "Use Audo to merge videos from clip.mp4."

## Questions

**How do I combine several videos into one MP4?** Add two to twenty video files at the top of the page, arrange them in the sequence they should play, and press Merge videos. Your clips open in order on the editor timeline so you can play through the joins and press Export to download one combined MP4.

**What happens when I merge videos that have different sizes or frame rates?** The first clip in your sequence sets the output resolution and frame rate (or you can pick a target aspect ratio under Frame). Subsequent clips are scaled to fit or fill that frame cleanly so mixed phone and laptop recordings play as one uniform video.

**Is there a transition between merged clips?** Each clip begins cleanly on the frame after the previous clip ends, so the merged video’s length equals the sum of your clips. To repeat a single clip with a crossfade at the seam, use Loop video.

**Can I stop one clip from sounding much louder than the next?** Yes. Turn on Even out loudness (under More in the editor’s Media panel) to measure each clip and match its overall volume toward the longest recording—helpful when stitching an intro recorded on a laptop mic onto a phone video.

**Will video still be exported if one clip has no sound?** Yes. Any silent clip receives silent audio for its portion of the timeline so the remaining clips keep their soundtracks in sync. Every input must contain a video track for the export to remain a video.

**Can I reorder or trim clips before exporting the merged video?** Yes. Drag clips into a new order in the Media panel, or switch to Cut to trim false starts and pauses off individual clips before you export the combined MP4. Your project stays saved in this browser so you can come back and adjust it anytime.

**Is it free?** Yes. Audo processes the first hour free, 10 times a day, without an account. The whole file costs $0.01 a minute ($0.60 an hour), charged only on success. No subscription. See pricing.

## More

- Every tool: https://audo.ai/llms.txt
- OpenAPI: https://audo.ai/api/openapi.json
- This page for people: https://audo.ai/merge-videos?utm_source=markdown&utm_medium=agent