Convert AVI to WebM
Convert AVI files to WebM entirely in your browser. Google's royalty-free web video format — VP9 + Opus, ~20–35% smaller than MP4. Drop your AVI below — vexo runs ffmpeg-wasm locally, nothing is uploaded.
Drop your video here
or choose a file from your device
Max 200 MB per file. Conversion runs in your browser.
Every conversion runs entirely in your browser. Your video never leaves your device.
About AVI → WebM
Why convert AVI to WebM?
WebM with VP9 + Opus is 20–35% smaller than MP4 at the same perceived quality, ideal for HTML5 <video> served from your own site. AVI is a legacy container with limited support on modern phones, browsers and editors. Converting to WebM keeps the footage but lets it play on everything you actually use today.
About AVI
AVI was Microsoft's standard video container from the mid-90s onwards. It still appears in old camcorder footage, CD-ROM archives, screen recorders and downloaded video from a decade ago. The container itself is fine, but it lacks modern features (streaming, timed metadata, chapters) and most browsers and mobile devices have quietly stopped supporting it. Converting to MP4 keeps the visual content but lets it play on phones, browsers and modern editors.
About WebM
WebM was designed for the open web. VP9 typically produces 20–35% smaller files than H.264 MP4 at the same visual quality, and Opus is the best general-purpose audio codec available. Every modern browser (Chrome, Firefox, Safari 14+, Edge) plays WebM natively. vexo encodes WebM with VP9 + Opus, and falls back to VP8 + Vorbis automatically if the wasm bundle lacks VP9.
What you're converting between
A short primer on both formats so the trade-offs are obvious before you hit Convert.
AVI
SourceAudio Video Interleave · introduced 1992
AVI was Microsoft's standard video container from the mid-90s onwards. It still appears in old camcorder footage, CD-ROM archives, screen recorders and downloaded video from a decade ago. The container itself is fine, but it lacks modern features (streaming, timed metadata, chapters) and most browsers and mobile devices have quietly stopped supporting it. Converting to MP4 keeps the visual content but lets it play on phones, browsers and modern editors.
Strengths
- Wide tooling on Windows desktops historically
Trade-offs
- Larger than modern containers at the same quality
- Spotty support in browsers and on mobile
- No streaming features, no chapters
WebM
TargetWebM · introduced 2010
WebM was designed for the open web. VP9 typically produces 20–35% smaller files than H.264 MP4 at the same visual quality, and Opus is the best general-purpose audio codec available. Every modern browser (Chrome, Firefox, Safari 14+, Edge) plays WebM natively. vexo encodes WebM with VP9 + Opus, and falls back to VP8 + Vorbis automatically if the wasm bundle lacks VP9.
Strengths
- Smaller files than MP4 at the same perceived quality
- Royalty-free, open codec
- Native playback in every modern browser
Trade-offs
- Older video editors (iMovie, older Premiere) may reject it
- Some social uploaders and legacy players prefer MP4
- Slower to encode than MP4 in ffmpeg-wasm
Popular conversions
Each link below opens the converter pre-tuned for that conversion.
Supported formats
MP4 is the safest default for web and mobile playback. WebM gives the smallest files for modern browsers. GIF is for short, soundless animations.
WMV, FLV and other legacy/streaming formats are not supported in this version. Please convert those to MP4 first using a desktop tool.
| Format | Input | Output | Notes |
|---|---|---|---|
| MP4 | Yes | Yes | H.264 + AAC, broadest compatibility |
| MOV | Yes | No | Apple/QuickTime container; convert to MP4 |
| WebM | Yes | Yes | VP9 + Opus, smaller than MP4 |
| MKV | Yes | No | Container; convert to MP4 or WebM |
| AVI | Yes | No | Legacy container; convert to MP4 |
| GIF | Yes | Yes | No audio, short clips only |
| WMV | No | No | Not supported |
| FLV | No | No | Not supported |
Frequently asked questions
Your videos never leave your device
vexo is a static page. Every conversion runs inside your browser via ffmpeg compiled to WebAssembly. There is no server-side processing, no upload, no temporary file, no cache. When you close this tab, every file is gone.
- No account required.
- No server processing. Your videos stay on your device.
- No caching, no Service Worker, no IndexedDB persistence.
- The conversion engine (ffmpeg-wasm) is fetched from a public CDN and cached by the browser; no personal data is sent.