Convert WebM to MP4

Create an H.264 MP4 from a supported WebM recording or downloaded clip.

Supported files: WEBM · One file, up to 200 MB

Quality

Smaller videos are not enlarged. Subtitles, extra tracks and HDR may not be kept.

Only codecs your browser supports can be converted.

  • Free
  • No sign-up
  • No file upload

Example result

Example settings: Quality Balanced · Maximum long edge 1280 px
Before · source.webm1.3 MB
After · webm-to-mp4-1.mp4694.1 KB

Convert WebM to MP4 · How to use this tool

  1. Choose a WebM video.

  2. Set the quality and maximum long edge.

  3. Check the picture and sound in the MP4, then download it.

Use WebM recordings in workflows that require MP4

Some editors and upload forms ask for MP4. This tool re-encodes the primary WebM video track to H.264 and converts retained audio to AAC when needed.

The output is a new compressed copy. It cannot recover detail missing from the WebM, and transparent video does not remain transparent in this MP4 output.

Supported files

WEBM → MP4

  • One file, up to 200 MB
  • Total output: 150 MB
  • Maximum duration: 10 minutes
  • Maximum video resolution: 3840×2160 · 4096 px

Frequently asked questions

Why convert a WebM recording to MP4?

Some sites and apps accept H.264 MP4 but not WebM.

What happens to Opus audio when WebM becomes MP4?

It must be converted to AAC. If this browser cannot do that, processing stops with an audio error instead of silently dropping sound.

Can WebM transparency be kept in the MP4?

No. This H.264 output does not preserve an alpha channel. Check the rendered background before sharing.

Will WebM to MP4 make a blurry recording sharper?

No. It changes the format, not the amount of detail in the source.

Are my files uploaded to a server?

No. Files are processed in your browser on this device and are not sent to BlurMe servers.

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