WebM to MP4 – Convert Online, Free, No Watermark
Chat shortcut: /webmtomp4
WebM to MP4 in two steps: upload the WebM, download the MP4. Meant for screen recordings from the browser and recording programs, when a program, a phone or a presentation expects MP4 with H.264.
No Sign-Up
Free · Input and result are automatically deleted 24 hours after upload.
Where WebM plays, where MP4 is expected and what the conversion does
WebM is an open video format for the web: browser screen recordings, recording extensions and many screen recorders save in it, usually with the VP8 or VP9 codecs. In the browser that works well; outside it, whether the file opens depends on the respective application and its codec. MP4 with H.264 is the more widespread format and is accepted by many editing, presentation and messaging programs.
The conversion re-encodes the picture to H.264 and the first audio track to AAC (160 kbit/s) and writes both into an MP4. The encoding is lossy and works with a fixed quality level (CRF 23) with no setting to adjust; how much of a difference from the original you see depends on the material. To judge for yourself, a quick look at text and fine lines in the result is worthwhile.
How it works
- 1
Upload the WebM
Drag the file into the box or select it, up to 96 MB, 15 minutes and 3,840 × 2,160 pixels per video frame.
- 2
Convert
Click “Let’s go”; there are no settings, picture and first audio track are converted to H.264 and AAC at a fixed quality level.
- 3
Download the MP4
Download the MP4 or carry straight on under “Continue with” to compress, trim or make a GIF.
Good to know
- Input: WebM; the box also accepts MP4, MOV, MKV, AVI, WMV, FLV and 3GP. Output: MP4 with H.264 (picture) and AAC (sound).
- Limits: 96 MB, 15 minutes and 3,840 × 2,160 pixels per video frame (4K), one file per run.
- The first video track and the first audio track are carried over; further audio tracks and embedded subtitles are left out. Transparent areas become a solid background, because the MP4 has no alpha channel.
- Processed on our server; input and result are deleted after 24 hours (hourly cleanup; an input that a more recent job is still using stays until that job’s deadline).
- Free, no sign-up and no watermark.
Frequently asked questions
Where do WebM files come from?
Browser screen recordings, recording extensions and many recording programs save in WebM (VP8/VP9). Whether an editing program, a phone or a presentation program opens the file depends on the respective application and its codec; MP4 with H.264 is more widely supported.
Will I lose quality?
The video is re-encoded to H.264 at a fixed quality level (CRF 23), so the conversion is lossy. How visible that is depends on the material; with screen recordings, a look at text and fine lines in the result is worthwhile. For a different quality level, use the Video Converter with its quality setting.
Is the sound kept?
Yes, the first audio track is converted to AAC at 160 kbit/s. If the WebM file has no sound, the MP4 has none either; further audio tracks are skipped.
What happens to transparency or subtitles?
The MP4 has no alpha channel: transparent areas from a WebM file get a solid background. Embedded subtitle tracks are left out during conversion; only the first video track and the first audio track make it into the result.
Why is the MP4 larger or smaller than the WebM file?
H.264 and VP9 compress differently, so the size can differ in either direction. If the file should get smaller, use “Video Compressor” afterward.
Does it work the other way around, MP4 to WebM?
Yes, the Video Converter converts to WebM, MOV, MKV or AVI.
How large can the file be and what happens to it?
Up to 96 MB, 15 minutes and 3,840 × 2,160 pixels per video frame. Input and result sit on our server for 24 hours and are removed in the hourly deletion run; an input you have meanwhile used in another tool stays until that job’s deadline. The conversion is free and needs no account.