WebM to MP4 Converter

Turn WebM recordings into MP4

WebM is the open video format used by browsers, so many screen recorders, webcam recorders and online meeting tools save their output as .webm files. It works well in Chrome and Firefox, yet iPhones, older versions of Windows, video editors, smart TVs and some upload forms still prefer MP4. This WebM to MP4 converter re-encodes the video to H.264 and the audio to AAC, the most widely supported combination, directly in your browser with ffmpeg.wasm. Your recordings are not uploaded anywhere, so internal demos, calls and tutorials stay on your device.

Quality and speed

WebM video uses VP8, VP9 or AV1, codecs that are not widely supported inside MP4 files, so the picture is re-encoded rather than simply copied. The quality presets control how much detail is kept: High is best for screen recordings with small text and sharp edges, Balanced is a good default for webcam footage and general clips, and Small file trims size for email and messaging. Opus or Vorbis audio is converted to AAC at 160 kbps. Encoding speed depends on your processor and the length and resolution of the video, and a progress bar shows how far along it is.

Tips for screen and webcam recordings

Browser-made WebM files sometimes lack duration information, which makes seeking difficult in some players; converting to MP4 writes a complete index and moves it to the start of the file for fast playback and streaming. Several files can be converted in one go, each with its own preview. Long recordings need free memory, so close other heavy tabs first. To shorten the clip or reduce its size further, follow up with the trim and compress tools on this site.