Do you want to convert a WebM file to the MP4 format? While this open source format is commonly found on HTML5 sites like YouTube, some video players may not support WebM videos. Fortunately, converting videos with the .webm file extension videos to MP4 is fast and easy. If you want to create an MP4 video that has the same resolution and size as the original file, you can use any video converter, including VLC Media Player, or an online converter that works on any platform. And if you want an easy way to decrease the video's quality and size, try HandBrake on your PC or Mac. This wikiHow guide teaches you 5 easy ways to convert a WebM video to the MP4 format.