webm The WebM extension is an HTML5 standard for distributing and viewing videos over the web. WebM is primarily designed for use on the web using the HTML5 tags <video> </video>. Its design is based on the Matroska container, video compression in the WebM file format is often done with VP8-enabled technology. WebM is a high quality, open-source, standard video format which lets users play videos on the web. It is specifically catered for video playback on the web and in web browsers. A unique aspect about the WebM extension is that it adapts to various bandwidths, processing environments, and is used over a wide range of media playing devices. The audio compression technology used in the WebM file extension is known as the OGG Vorbis Compression.
ac3 Files with the .ac3 filename extension refer to the proprietary audio file format Dolby digital AC-3, developed by Dolby Laboratories. The AC-3 format is from the lossy family of audio compression formats. It supports a variety of audio channel configurations and was the first of its kind to support the full surround sound experience. Because of this, the format has been commonly used in the development of motion picture features designed for theaters and in consumer homes through DVDs and surround sound home theater systems. The AC-3 format is one of the supported audio codecs of the ATSC standard ' a set of standards developed for digital television transmission in several affiliated countries.