NoCloud Media

Video tool

Video Converter

Convert between the video formats people actually use. Runs in your browser — nothing uploads.

How it works

  1. 1

    Drop your video

    MP4, MOV, WebM, MKV, AVI, or M4V. Stays on your device.

  2. 2

    Pick an output format

    MP4 for almost everywhere, MOV for Apple, WebM for the web, MKV for flexibility, AVI for legacy.

  3. 3

    Convert in your browser

    We re-encode to the right codec for each container: H.264 + AAC for MP4/MOV/MKV/AVI, VP8 + Vorbis for WebM.

  4. 4

    Download the converted video

    Original stays untouched. Converted file is yours alone.

Why use Video converter?

Private — your video never leaves your browser, so even personal or pre-release footage can be converted safely.

Covers the five formats that matter — not every container Wikipedia lists, but the ones people actually deal with.

Sensible codecs per container — you don't have to think about whether VP9 is supported in MP4 (it isn't, widely) or whether H.264 works in WebM (it doesn't).

Common use cases

  • Convert a MOV from an iPhone to MP4 for a Windows laptop
  • Turn an MKV rip into MP4 for a browser video player
  • Export a WebM screen recording as MP4 for a social platform
  • Change an AVI to MP4 to shrink the file and fix playback
  • Produce a WebM for an open-web site that avoids proprietary codecs
  • Remux an unusual container into something your NLE will accept

About MP4 and MP4

Different containers support different codecs. MP4, MOV, MKV, and AVI all accept H.264 + AAC, so NoCloud Media uses that combination for all of them (CRF 23, AAC 128 kbps). WebM is part of the open-web stack and accepts VP8/VP9 video with Vorbis/Opus audio; we pick VP8 + Vorbis for the broadest support in FFmpeg's default WebAssembly core. MP4 and MOV also get `+faststart` so playback begins as soon as the first chunk arrives.

Frequently asked questions

Is my video uploaded to a server?
No. NoCloud Media converts your video entirely in your browser using WebAssembly. Your file never leaves this tab.
Why is re-encoding so slow?
Video encoding (especially H.264) is CPU-heavy. In the browser it runs through WebAssembly, which adds overhead versus native FFmpeg. A 5-minute HD clip often takes a few minutes on a laptop; longer on mobile.
Can you just remux — change container without re-encoding?
Not in this tool. If your source codecs happen to fit the target container, a remux would be faster and lossless, but detecting that automatically is fragile. A dedicated remux tool may come later.
Will quality drop?
Yes, slightly. Re-encoding is always lossy relative to the previous encode. At CRF 23, the difference is hard to see at typical viewing distances. For archival use, prefer a format that can remux (like MKV) over re-encoding.
What's the maximum file size?
It depends on your browser's available memory. Files up to 500MB work smoothly; files up to around 2GB may work on desktop browsers with enough RAM.
Which browsers are supported?
Chrome, Edge, Firefox, and Safari 15+. We require WebAssembly and SharedArrayBuffer, both standard in modern browsers.

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