What is .webm?
.webm is an open, royalty-free media container format designed specifically for the web. It typically uses VP8/VP9 or AV1 for video and Opus or Vorbis for audio, providing efficient compression and high quality for HTML5 video playback.
This quick guide explains when to use .webm files, how to open them on any device, and how to share them instantly with FileXhost.
When to use .webm files
- You are serving videos on modern websites and want great compression efficiency.
- You want a royalty-free alternative to H.264-based MP4 for browsers.
- You are optimizing page performance and Core Web Vitals with lightweight media.
- You need transparency or looping video effects for UI elements.
How to open .webm files
WebM files are supported natively in most modern browsers (Chrome, Firefox, Edge, and many Chromium-based browsers) via the HTML5 video element. On desktop, players like VLC and MPV also support WebM. You can upload .webm files to FileXhost to embed or share them with an HTML5-friendly video player.
Algorithm details
WebM is based on the Matroska container but restricted to a specific set of codecs optimized for web delivery. Historically, it used VP8/VP9 for video and Vorbis/Opus for audio. Today, AV1 is increasingly used in WebM for even better compression, especially at lower bitrates, while remaining royalty-free.
Browser & platform support
- Desktop: Excellent support in Chrome, Firefox, Edge, and Opera. Safari support depends on version and codec (AV1/VP9 support is improving).
- Mobile: Strong support on Android (Chrome/Firefox). iOS support is more limited and often requires recent versions or specific codecs.
- OS: Supported wherever modern browsers or players like VLC/MPV are available.
Format comparison
| Feature | Details |
|---|---|
| Compression | Often smaller than H.264 MP4 at comparable quality, especially with VP9/AV1. |
| Licensing | Open and royalty-free, unlike many H.264/H.265 deployments. |
| Compatibility | Excellent in modern browsers, weaker on older devices and some legacy systems compared to MP4. |
| Use Case | Ideal for web video, background loops, and performance-focused sites. |
How to create webm files
- Encoders: FFmpeg, HandBrake, Shutter Encoder (encode to VP9/Opus or AV1).
- Screen Capture: Some browser-based tools and encoders export directly to WebM.
- Video Editors: Many NLEs export WebM via plugins or intermediate tools.
How to convert webm files
- FileXhost: Upload WebM to host and embed using standard HTML5 video.
- Desktop: HandBrake, VLC, Shutter Encoder (MP4 <-> WebM).
- CLI: FFmpeg (ffmpeg -i input.mp4 -c:v libvpx-vp9 -c:a libopus output.webm).
Advantages & disadvantages
Advantages
- Excellent compression efficiency for web delivery
- Royalty-free and open-source friendly
- Optimized for HTML5 video and modern web browsers
- Supports modern codecs like VP9 and AV1
Disadvantages
- Less support on older devices and some hardware decoders
- Safari/iOS support lags behind Chromium-based browsers
- Not as universally recognized as MP4 outside the browser environment
Tools & software
Players
All modern browsers, VLC, MPV, MPC-HC
Encoders
FFmpeg, HandBrake, Shutter Encoder
Streaming Platforms
Many CDNs and players support WebM as an alternate or primary format
Frequently asked questions
Is WebM better than MP4?
For modern browsers and performance-focused sites, WebM (with VP9 or AV1) often provides smaller file sizes at similar quality. However, MP4 with H.264 offers better compatibility with older devices and some hardware decoders. Many sites serve both and let the browser choose.
Can I use WebM for all my site videos?
You can for modern audiences, but for maximum compatibility it's best to offer an MP4 fallback for older devices and certain browsers. The HTML5 <video> tag makes it easy to provide multiple sources.
Does WebM support transparency?
Yes, WebM with VP8/VP9 can support alpha channels, which makes it useful for UI animations and overlay effects as a more efficient alternative to animated GIF or APNG in some cases.
How do I convert MP4 to WebM?
Use tools like HandBrake or FFmpeg. For example: ffmpeg -i input.mp4 -c:v libvpx-vp9 -b:v 0 -crf 30 -c:a libopus output.webm. Adjust CRF for quality/size trade-offs.
Technical specs
- File type
- Video
- Extension
- .webm
- MIME type
- video/webm
- Compression
- Lossy
- Max file size on FileXhost
- Up to 25 MB per file on the free plan and up to 1 GB on Pro FileXhost accounts.
Share .webm files instantly
Upload your .webm file to FileXhost to get a clean, shareable URL in seconds. View the file in a modern browser, protect access with optional settings, and let others download it without any confusing ads or cluttered file pages.
Upload .webm file