How to convert WebM to MP4

Updated 28 October 2026 · 4-minute read

WebM is a common web video format, and Chrome plays it perfectly. But plenty of other places don't: older video editors, some versions of PowerPoint, iPhone apps. Converting to MP4 fixes that.

Why WebM usually needs a real conversion

Unlike TS to MP4, where you can often just move the video into a new container, WebM usually uses different codecs (VP8, VP9 or AV1 video with Opus or Vorbis audio). For an MP4 that plays everywhere, the video gets re-encoded to H.264 and the audio to AAC. That takes longer, but it's reliable.

Method 1: ffmpeg (best quality control)

ffmpeg -i input.webm -c:v libx264 -crf 20 -c:a aac output.mp4

-crf 20 keeps quality high. Lower numbers mean better quality and bigger files; 18 to 23 is the usual range.

Method 2: VLC (no command line)

In VLC, choose Media → Convert / Save (Mac: File → Convert / Stream), add the WebM file, pick the profile Video – H.264 + MP3 (MP4), and start.

Method 3: HandBrake (friendliest)

Open the file in HandBrake, choose a preset like Fast 1080p30, make sure the format is MP4, and click Start.

Do you need to convert at all?

For watching on a computer, no: Chrome and VLC play WebM directly. Convert when the destination is an editor, a presentation, or an Apple device. (Putting a video in PowerPoint.)