Convert WebM to AVI
To convert WebM to AVI, add your .webm file below and press the button: it's processed on your own device and you download the result, with nothing uploaded. It's free, needs no account, and works with files up to 500MB.
About converting WebM to AVI
WebM (.webm) files can be converted to AVI entirely in your browser — no software to install, no file upload, and no account required. The conversion runs on a WebAssembly build of ffmpeg directly on your device.
Technical comparison
| WebM | AVI | |
|---|---|---|
| Category | video | video |
| Compression type | Lossy (VP8/VP9/AV1 video, Vorbis/Opus audio) | Varies (codec-dependent; often uncompressed or lightly compressed) |
| Typical file size | Small to moderate — typically smaller than an equivalent MP4 at the same quality | Large — often stores uncompressed or lightly-compressed video |
| Transparency support | Yes (VP8/VP9 support an alpha channel) | No |
How to convert WebM to AVI privately
Every step below runs on a WebAssembly build of ffmpeg inside this browser tab. Your .webm file is never uploaded to a server — there's no network request carrying it anywhere.
Add your WebM file
Drag and drop, or click to select, a file (.webm). It's read straight from disk into browser memory — no upload step exists.
Convert locally
FreePrivateConvert converts it to AVI using a WebAssembly build of ffmpeg, entirely within this browser tab.
Download the result
Save your converted .avi file. It only ever existed in this tab's memory — closing the tab without downloading discards it completely.
Convert WebM to AVI with ffmpeg (command line)
Prefer the terminal? This is the exact ffmpeg command this page runs for you:
ffmpeg -i input.webm -c:v libx264 -preset veryfast -crf 23 -c:a aac output.avi- -i input.webm
- Your WebM file.
- -c:v libx264
- Encode the video as H.264, the format virtually every phone, browser and TV plays.
- -preset veryfast
- Encoding speed vs. file size trade-off: veryfast encodes quickly with a slightly larger file.
- -crf 23
- Constant quality level (lower = better quality and bigger file; 18-28 is the usual range, 23 is the default).
- -c:a aac
- Encode the audio as AAC.
- output.avi
- The AVI file to create. ffmpeg picks the container from this extension.
Don't have ffmpeg installed? You don't need it: use the converter at the top of this page. It runs the same conversion on your own device, and your file is never uploaded.
FAQ
- Is my file uploaded anywhere?
- No. Your file is read and processed inside this browser tab and never leaves your device. You can confirm it in your browser's developer tools: the Network tab shows no upload.
- Does converting WebM to AVI reduce quality?
- The video is re-encoded as H.264 at CRF 23 (ffmpeg's default quality level, "veryfast" preset) with AAC audio. That looks very close to the source for most footage, but it is a lossy re-encode, so fine detail and grain can soften slightly.
- Is there a file size limit?
- Yes: 500MB per file. There's no account and no limit on how many files you convert.
- What's the difference between WebM and AVI?
- WebM and AVI (Audio Video Interleave) store data differently. WebM: lossy (VP8/VP9/AV1 video, Vorbis/Opus audio). AVI: varies (codec-dependent; often uncompressed or lightly compressed). AVI is a Microsoft container format dating to 1992 — still turns up in older camcorder footage and legacy software exports, but obsolete for modern delivery.
- Why convert WebM to AVI?
- Common uses for AVI: Playing back old camcorder or capture-card footage; Legacy CCTV/DVR exports; Archived software-generated video. Extremely simple, well-documented container structure with minimal parsing overhead for old hardware and software.
- What MIME type does a .avi file use?
- video/x-msvideo, the standard type for Audio Video Interleave.
- What is the ffmpeg command to convert WebM to AVI?
- Run: ffmpeg -i input.webm -c:v libx264 -preset veryfast -crf 23 -c:a aac output.avi. This is the exact command FreePrivateConvert runs for this conversion, so you can use this page instead of installing ffmpeg: it runs the same conversion inside your browser.
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