WebM is a digital video file format developed by Google for use on the web. It is an open, royalty-free format designed to provide high-quality video with efficient compression, making it ideal for use on the web. WebM files are typically compressed using the VP8 or VP9 video codecs, which provide high-quality video at a lower bitrate compared to other video codecs like H.264. The format also supports Opus or Vorbis audio codecs for high-quality audio. WebM files can be played back on a variety of web browsers and media players, including Google Chrome, Mozilla Firefox, and VLC media player. They can also be converted to other video file formats like MP4 or AVI using compatible media conversion software. Overall, WebM is a useful video file format for web-based video content distribution, particularly for websites that want to provide high-quality video while keeping file sizes relatively small.