What happens when you convert MP4 to WebM
| Inside a typical MP4 | H.264 or HEVC (H.265) video with AAC audio |
|---|---|
| Copy without re-encoding | Rarely: the codecs are not compatible, so the video is re-encoded |
| When re-encoded | VP8 video with Vorbis audio |
| Opens in | all current browsers and VLC; iPhone apps, PowerPoint and many editors do not |
Sizes are typical values; your files will vary with content and settings.
MP4 MPEG-4 Part 14
MP4 is the universal video container. With H.264 video and AAC audio it plays on every phone, browser, smart TV and social network, which makes it the safest choice for sharing.
MP4 converterWebM WebM Video
WebM is an open, royalty-free container built for the web, usually holding VP8 or VP9 video with Opus or Vorbis audio. Browser screen recorders and many web apps save WebM by default.
WebM converterHow to use the MP4 to WebM Converter
- 1
Choose a MP4 file or drop it onto the page.
- 2
Review the video options. The defaults suit most files.
- 3
Click Convert and download your WebM when processing finishes.
Why convert MP4 to WebM?
MP4 is what phones, cameras, screen recorders and most video sites produce. Editing software sometimes prefers intra-frame formats like ProRes for heavy editing. Choose WebM to embed video on a website using open, royalty-free codecs.
Frequently asked questions
Will the WebM lose quality?
Both formats are lossy, so converting re-encodes the data once more. Using a high quality setting keeps the generational loss very small. Avoid converting the same file back and forth repeatedly.
Does converting MP4 to WebM re-encode the video?
Rarely: the codecs are not compatible, so the video is re-encoded. A typical MP4 contains H.264 or HEVC (H.265) video with AAC audio. Otherwise the result is VP8 with Vorbis audio.
Questions about privacy, file-size limits or conversion speed are answered in the general FAQ.