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Loading FFmpeg

Downloading video engine (~30 MB, one time)...

Cached after first load — works offline

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SilentCanoe Utilities /
🎬 Video Converter
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100% Local — No uploads

Free Video Converter — In Your Browser

Powered by FFmpeg WebAssembly. Convert any video format, extract audio, create GIFs — entirely on your device.

✓ MOV, MKV, AVI, WMV, FLV → MP4 ✓ Extract audio as MP3 / WAV / OGG ✓ Create optimized GIFs ✓ Scale to 1080p / 720p / 480p ✓ Trim start & end ✓ Zero uploads
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All processing happens entirely in your browser using FFmpeg WebAssembly. Your video never leaves your device — not even a single byte is uploaded. Works offline after first load.

Drop file
Configure
Convert
Download
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Drop your video here

or click to browse — any video format supported

MP4 MOV MKV AVI WebM WMV FLV 3GP M4V TS + more

Large files (>1 GB) need sufficient browser memory. Processing happens entirely in RAM.

Frequently Asked Questions

How does browser-based video conversion work?

This tool uses FFmpeg compiled to WebAssembly — the same powerful encoder used by video professionals, running entirely inside your browser tab. The ~30 MB engine is downloaded once and cached. No server ever receives your video.

Which formats are supported?

Input: MP4, MOV, MKV, AVI, WebM, WMV, FLV, 3GP, M4V, TS/MTS, OGV, and most other container formats. Output: MP4 (H.264), WebM (VP9), MOV, MKV, GIF, APNG, MP3, WAV, and OGG.

Why does it need a service worker?

FFmpeg WebAssembly requires SharedArrayBuffer for fast memory access, which browsers restrict to cross-origin-isolated pages. This tool uses a lightweight COI Service Worker to automatically inject the required COOP and COEP headers on the client side — no server configuration needed. On your very first visit the page reloads once (in under a second) to activate the worker; subsequent visits load instantly.

What quality setting should I pick?

Ultra (CRF 18) is visually indistinguishable from the original — ideal for archiving. High (CRF 23) is the default H.264 setting with excellent quality. Medium (CRF 28) gives good quality at noticeably smaller file sizes. Low (CRF 35) creates the smallest files with visible compression artefacts.

How do I get the best quality GIF?

This tool uses a two-pass palette generation method — it first analyses the video to build a custom colour palette, then uses that palette when encoding. This is the highest-quality GIF method available. Keep frame rate below 15 fps and trim the video to under 10 seconds for manageable file sizes.

Why is conversion slow?

Video encoding is extremely CPU-intensive — even dedicated hardware encoders take time. WebAssembly runs at roughly 60–80% of native speed. A 1-minute 1080p video typically takes 30–90 seconds. Choosing a lower quality preset or smaller resolution significantly speeds things up.