Video Compressor — Free, No Upload
Compress MP4, MOV, AVI, MKV and WebM using your browser's native hardware codec. 4 quality presets. Nothing uploaded.
All Major Formats
MP4, MOV, AVI, MKV, WebM — input any format your browser can play.
4 Quality Presets
High Quality, Balanced, Small File, Tiny — bitrate scaled to your video resolution.
No Upload — Ever
Hardware-accelerated MediaRecorder runs on your device. Nothing sent anywhere.
Why compress video in your browser?
Most online video compressors — Clideo, Kapwing, Compress Video Online — upload your entire video to their servers before processing. For a 500MB video that means 500MB uploaded, often on a slow connection, to infrastructure you don't control.
This tool uses the browser's built-in MediaRecorder API with your device's hardware video encoder. Compression is fast, private, and requires no downloads — it just works.
Preset guide
| Preset | Target bitrate | Best for |
|---|---|---|
| High Quality | ~60% of original | Archiving, editing source files |
| Balanced | ~35% of original | Sharing, email, messaging |
| Small File | ~18% of original | Web embeds, social uploads |
| Tiny | ~8% of original | Maximum compression, small previews |
Frequently asked questions
How does browser-based video compression work?
The tool uses the MediaRecorder API — a built-in browser feature that records a canvas stream using your device's native hardware-accelerated video codec (VP9 or VP8). Your video plays through an offscreen canvas while the codec re-encodes it at a lower bitrate, all locally on your device.
How long does compression take?
Compression happens in real time — it takes roughly as long as the video duration. A 30-second clip compresses in about 30 seconds. This is much faster than software-based approaches because the browser uses your GPU's hardware video encoder.
Are my videos uploaded to a server?
No. The MediaRecorder API runs entirely in your browser using your local hardware. Your video file never leaves your device at any point.
What input formats are supported?
Any format your browser can play — typically MP4, MOV, WebM, AVI, MKV and M4V. The browser's native video decoder handles the input, so compatibility is excellent on all modern browsers.
What format is the output?
The output is a WebM file encoded with VP9 or VP8 — whichever your browser supports. WebM is supported by all modern browsers, Chrome, Firefox, Edge and Safari. For maximum compatibility you can convert the WebM to MP4 using the same tool after compression.
What do the quality presets control?
Each preset sets a target video bitrate scaled to your video's resolution. High Quality targets ~60% of the original bitrate; Balanced targets ~35%; Small File targets ~18%; Tiny targets ~8%. The actual file size depends on the video content — static scenes compress much more than fast action.