Browser screen recorders, OBS presets, Loom exports and many downloads produce WebM files. Browsers love them; iPhones, PowerPoint, Premiere, WhatsApp and many upload forms do not. ConvertCove turns WebM into a standard H.264 MP4 without sending your recording anywhere, which matters when the screen shows private data.
How to convert WEBM to MP4
- Click Select WEBM files or drag them onto the box above. You can add as many as you like.
- Check that the target says MP4. Click the slider icon next to a file to change its options.
- Press Convert. Each file shows its own progress, and the work happens on your device.
- Download files one by one, or use Download all (ZIP). Press Convert more to start a new batch.
Long screen recordings encode faster at 720p. Text at 720p is still readable for most presentations, and the file is about half the size.
WEBM vs MP4
What is WEBM?
WebM is Google’s royalty-free video format: a Matroska-based container with VP8, VP9 or AV1 video and Opus or Vorbis audio. Screen recordings made in Chrome are usually VP8 or VP9 and sometimes have a variable frame rate. More about the WEBM format.
What is MP4?
MP4 with H.264 and AAC is the format that every device and editor imports without fuss. It is also what most social platforms transcode to anyway, so uploading MP4 avoids a second round of quality loss. More about the MP4 format.
| WEBM | MP4 | |
|---|---|---|
| Full name | WebM video | MPEG-4 video |
| Extensions | .webm | .mp4, .m4v |
| MIME type | video/webm | video/mp4 |
When to convert WEBM to MP4
- You recorded your screen in the browser and need to play it on an iPhone or in Keynote.
- PowerPoint, Premiere or iMovie refuses to import the WebM.
- A support portal or LMS accepts MP4 uploads only.
- You want to send the clip on WhatsApp or iMessage.
Quality and settings
The VP8/VP9 video is decoded and re-encoded with x264. Balanced quality (CRF 23) keeps text in screen recordings sharp; choose High if the recording contains small code or spreadsheet text, and Small file for talking-head clips. Variable frame rate recordings are converted to a constant rate that players handle reliably. Opus audio becomes AAC at 160 kbps. If you only need the voice-over, convert to MP3 instead; it takes a fraction of the time.