MP4 to WebM
Related: Compress video · MP4 to GIF
WebM output
MP4 to WebM for modern browsers
This tool re-encodes your video to WebM using VP9 and Opus (unless you strip audio). FFmpeg scales frames to respect your max width, then applies your CRF and speed preset so you can balance quality, encode time, and file size.
For destinations that still expect H.264 in an MP4 shell, use compress video and pick MP4 there. WebM shines when you control playback in the browser or ship to platforms that accept it. When you want to switch between MP4 and WebM outputs in one session, video converter lets you choose the container per batch.
Quick reference
- Max width
- Downscales wide sources; smaller values reduce bytes.
- CRF
- Quality bias for VP9; lower is sharper and heavier.
- Preset
- Slower presets spend more CPU searching for efficiency.
- Audio
- Opus bitrate applies when audio is kept; remove for silent video.
MP4 to WebM questions
What is WebM used for?
WebM is a container aimed at the web, usually with VP9 video and Opus audio. Modern browsers play it well; it can be smaller than H.264 for similar quality on some clips, which helps pages load faster.
What does CRF mean for VP9?
CRF targets quality instead of a fixed bitrate: lower values keep more detail and larger files, higher values shrink the file with more risk of banding or softness in motion and gradients.
Should I strip audio?
If you only need silent loops or background video, removing audio cuts size and avoids an extra encode pass on audio. Keep audio when the soundtrack matters.
How is this different from compress video?
This tool always outputs WebM (VP9 + Opus). The general compress tool also offers MP4 (H.264) when you need maximum player compatibility.