WebM to MP4

WebM plays in browsers and almost nowhere else. This is the conversion for getting web video into a video editor, a phone gallery, or a TV.

Runs in your browser // nothing is uploaded

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What survives the conversion

Derived from what each format is able to store, not from what the conversion promises.

Kept

Audio track
Metadata
Chapters, which WebM could not store

Lost

Alpha channel

Settings used

Re-encoded from VP8 or VP9 to H.264 at CRF 23, audio to AAC.

When not to convert

Not for putting the video back on a website. WebM is smaller at matched quality.

About these formats

Video

What is a WebM file?

WebM is a royalty-free video container introduced by Google in 2010, normally carrying VP8, VP9 or AV1 video with Vorbis or Opus audio. At the same visual quality it is usually smaller than an H.264 MP4, and it supports true alpha transparency, which MP4 in practice does not.

Read the format guide

Video

What is a MP4 file?

MP4 is a container rather than a codec: it usually holds H.264 video with AAC audio, which is the single most widely playable combination on the internet. It supports subtitles, chapters and multiple audio tracks, and streams well because metadata can sit at the front of the file.

Read the format guide

Common questions

Does converting WebM to MP4 lose anything?

Yes. Alpha channel cannot be carried into MP4 and is dropped. WebM plays in browsers and almost nowhere else. This is the conversion for getting web video into a video editor, a phone gallery, or a TV.

Are my files uploaded when I convert WebM to MP4?

No. The conversion runs in your browser tab, so the file is never transmitted and the page works offline once loaded.

What settings does Filoven use for WebM to MP4?

Re-encoded from VP8 or VP9 to H.264 at CRF 23, audio to AAC.

When should I not convert WebM to MP4?

Not for putting the video back on a website. WebM is smaller at matched quality.