NoCloud Media

Video tool

Video Compressor

Shrink any video with a quality preset. Works in your browser — nothing uploads.

How it works

  1. 1

    Drop your video

    MP4, MOV, WebM, MKV, AVI, or M4V. The file stays on your device.

  2. 2

    Pick a quality preset

    Best, Balanced, Smaller, or Smallest. Lower quality means a smaller file.

  3. 3

    Compress in your browser

    We re-encode the video with H.264 at the CRF matching your preset. Audio is re-encoded to AAC at 128 kbps.

  4. 4

    Download the compressed MP4

    Output is MP4 with `faststart` enabled for quick playback in browsers and social apps.

Why use Video compressor?

Private — your video stays on your device, so even large personal recordings can be compressed safely.

Predictable — each preset maps to a specific CRF value. `Balanced` is CRF 23, the same quality default most streaming services use.

Fast delivery — output is MP4 with `+faststart` so playback begins as soon as the first chunk loads.

Common use cases

  • Shrink a 4K phone video to something you can email
  • Compress a screen recording for an issue tracker upload
  • Reduce a long gameplay capture before posting to a forum
  • Cut the size of a wedding video for cloud backup
  • Make a video small enough for a size-limited chat app
  • Prep a short for social where platforms re-compress anyway

About MP4 and MP4

H.264's Constant Rate Factor (CRF) is a quality target: the encoder spends as many bits as it needs to hit that quality, regardless of scene complexity. CRF 18 is visually lossless, CRF 23 is the x264 default that streaming services use, CRF 28 trades noticeable detail for much smaller files, CRF 32 is noticeably compressed. NoCloud Media maps four presets to those CRF values. We always re-encode audio to AAC at 128 kbps for MP4 container compatibility. The `+faststart` flag moves the MP4 `moov` atom to the front of the file so players can start streaming immediately.

Frequently asked questions

Is my video uploaded to a server?
No. NoCloud Media compresses your video entirely in your browser using WebAssembly. Your file never leaves this tab.
Why is my output bigger than I expected?
If the source was already compressed heavily, a conservative preset (Best or Balanced) can produce a file that's similar in size or slightly larger. Pick a more aggressive preset (Smaller, Smallest) for more reduction.
Can I preserve the original audio?
Not in this tool — we re-encode audio to AAC 128 kbps for consistent MP4 compatibility. For a lossless video remux with the same audio, try the video converter once output-container compatibility matches.
Why is it slow?
H.264 encoding is CPU-intensive. In a browser it runs in WebAssembly rather than native code, which adds overhead. Expect a few minutes for a 5-minute HD clip on a laptop; longer on mobile.
What's the maximum file size?
It depends on your browser's available memory. Files up to 500MB work smoothly; files up to roughly 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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