Convert WebM to MP4
Usually nothing is re-encoded: the tracks go into MP4 as they are, in seconds and with no loss.
They open in the converter with MP4 selected.
Browse filesFiles stay on your device. Going the other way? MP4 to WebM
What changes
WebM files normally carry VP9 video and Opus audio, which MP4 accepts as they are, so the converter copies the tracks untouched: in seconds and with no loss. If not, or if you change the quality, size, scale or trim, the video is decoded and compressed again, and loses a little more detail.
If it’s copied, it’s about the same size as the WebM: only the container changes. If it’s re-encoded, the size stays about the same.
Watch out for transparency: WebM has an alpha channel and MP4 doesn’t, so transparent areas are filled with the background color (white unless you pick another).
When it’s worth it
Choose MP4 for: Phones, websites, social networks, and TV. Small files for the quality, usually with H.264 or H.265 inside.
Stay with WebM for: Websites and browser playback.
How to convert WebM to MP4
- Drop the WebM files on this page, or browse for them. Up to 200 at once.
- The converter opens with the files loaded and MP4 selected.
- Press Convert, then save each file or all of them as a ZIP.
Questions
Does converting WebM to MP4 lose quality?
Usually not. With the default settings the tracks are copied without re-encoding. Quality only drops if you change the quality, size or trim, or if the file uses a codec MP4 doesn’t accept.
What is the MP4 format?
A container that holds a video track, one or more audio tracks and metadata, and nothing else: which codec sits inside is a separate question. H.264 or H.265 video with AAC audio is the combination almost everyone means by MP4.
What is the WebM format?
The container Google designed for the web, carrying VP8 or VP9 video with Opus or Vorbis audio. It’s royalty-free, which is why open-source projects and most browsers prefer it.
Are the files uploaded?
No. The file is opened in this tab, converted here and saved from here. There’s no account and no watermark.
How many files can be converted at once?
Up to 200 per batch and about 2 GB per file, within the memory this device has available.