This tool is used to convert Media Player 4 (mp4) to Web Media (webm).

MP4 is a digital multimedia container format most commonly used to store video and audio, but can also be used to store other data such as subtitles and still images.

WebM is an audiovisual media file format. It is primarily intended to offer a royalty-free alternative to use in the HTML5 video and the HTML5 audio elements. It has a sister project WebP for images.