Convert MP4 to WebM
Settings
No file yet
Settings appear after you choose a file.
A clip headed for a web page is often supplied as WebM, an open video format built for the web. The converted file is a WebM version of the MP4.
MP4 or WebM?
Keep MP4 when
- It is the original. Encoding it again loses a little detail.
Pick WebM when
- A website or an app asks for WebM files.
About MP4 and WebM
MP4
The most widely used video format. It plays on most phones, computers and platforms, and is the usual way video is shared.
WebM
An open video format made for the web. Common for screen recordings and clips saved from sites, less so in media players.
Questions
Does the WebM look worse?
A little. VP9 is lossy, so encoding the video again drops some detail. A lower CRF loses less.
Which codecs go in the WebM?
The Terminal lines write VP9 video and Opus sound. VLC's WebM profile writes VP8 video and Vorbis sound, which a WebM also takes.
Which CRF should I pick?
The commands use CRF 32 for VP9, a common middle ground between size and quality. Change -crf 32 to a lower number for a better picture and a larger file, or a higher one for a smaller file, 0 to 63.
Is there a copy line?
No. A WebM takes only VP8, VP9 or AV1 video, so an MP4 with H.264 video has to be encoded again.
Can I convert a whole folder at once?
Yes. Drop them all here. In Terminal, one line converts every MP4 in the folder.