Browser FFmpeg recipe
Convert Video to WebM Online with FFmpeg
Create a WebM file with VP9 video and Opus audio.
Command
Run this FFmpeg command
ffmpeg -i input.mp4 -c:v libvpx-vp9 -crf 32 -b:v 0 -c:a libopus -b:a 96k output.webmWhen to use it
- web embeds
- open web video
- smaller web previews
How it works
- Upload the source video.
- Run the VP9 and Opus WebM command.
- Download the generated WebM file.
Option reference
| Option | What it does |
|---|---|
-c:v libvpx-vp9 | Encodes video with VP9. |
-crf 32 -b:v 0 | Uses quality-based VP9 encoding. |
-c:a libopus | Encodes audio with Opus. |
Practical notes
- VP9 can be slower than H.264 in the browser.
- Lower CRF values improve quality and increase file size.
FAQ
Is WebM smaller than MP4?
It can be, but the result depends on the source, settings, and browser performance.
Why use Opus audio?
Opus is a common audio codec for WebM and works well at lower bitrates.