WebM to MP4
Screen recordings from Chrome, OBS and many websites are saved as WebM, which iPhone, WhatsApp and many networks do not accept. The tool turns WebM into an MP4 with H.264 picture and AAC sound, which plays on every device. The picture is encoded at high quality, and if the WebM is already H.264 it is copied with no loss. The video never leaves your device.
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How to use: WebM to MP4
Choose a WebM
Add a WebM video up to 380 MB, such as a screen recording.
Choose the mode
Plays everywhere for H.264 and AAC, or keep the original format where MP4 allows it.
Download the MP4
Watch the result in the player and download the MP4.
Frequently asked questions
Why does WebM not work on iPhone and WhatsApp?
WebM usually carries VP8 or VP9 picture and Opus or Vorbis sound, which iPhone, WhatsApp and many networks do not accept. An MP4 with H.264 picture and AAC sound plays everywhere, so that is the default.
Is quality lost?
VP8, VP9 and AV1 picture is re-encoded as H.264 at a higher data rate than the original, so the difference is usually invisible. If the WebM already has H.264 picture, it is copied with no loss at all.
What does Keep the original format mean?
VP9 or AV1 picture and Opus sound are copied into the MP4 without re-encoding. That is faster and lossless, but not every phone and program opens such an MP4.
How long does it take?
Re-encoding runs on your device, on a recent computer faster than the length of the recording. Copying without re-encoding takes a few seconds.
Does it work with MKV files?
Yes, but there is MKV to MP4 for those, which explains what happens to sound and subtitles from films.