.webm

What is a .webm file?

WebM is Google's open video format — VP8/VP9 or AV1 video with Vorbis/Opus audio, optimised for web streaming.

Safe format
Type Video
By Google
MIME video/webm

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What is it

You're watching a video on a website and it's a WebM file — Google's open video format designed specifically for the web. WebM uses VP8/VP9 or AV1 video codecs with Vorbis/Opus audio, producing files that are often smaller than equivalent MP4s at the same visual quality.

Google developed WebM as a royalty-free alternative to H.264/MP4, which requires licensing fees (that browser vendors have been willing to pay). YouTube serves VP9-encoded WebM for most of its content. Chrome, Firefox, Edge, and Opera play WebM natively. Safari added VP9/WebM support in later versions. The format is particularly popular for web-embedded video, screen recordings shared online, and platforms that prioritise open standards.

Every modern browser plays WebM natively. VLC plays WebM files on any platform. For sharing video outside the web (sending to someone's phone, uploading to a platform that expects MP4), convert with <a href="https://fwip.app/tools/webm-to-mp4/">fwip</a>. The conversion is straightforward — WebM and MP4 are just different containers, and the video data often doesn't need re-encoding.

Technical details
Full Name
WebM Video
MIME Type
video/webm
Developer
Google
Magic Bytes
1A 45 DF A3
Safety
.webm is a known, safe format.
What opens it
Any modern browser
FREE All
VLC
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Convert with fwip

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FAQ
Is WebM better than MP4?
WebM (with VP9) often achieves similar quality at smaller file sizes compared to MP4 (with H.264). The trade-off is compatibility — MP4 plays everywhere, while WebM is primarily a web format. For web delivery, WebM is excellent. For universal sharing, MP4 is safer.
How do I convert WebM to MP4?
Use fwip for instant browser-based conversion. VLC can also convert via Media → Convert/Save. If the WebM uses VP9 video, the conversion may re-encode to H.264 for MP4 compatibility.
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