m4v M4V is a file format developed by Apple for the iTunes store's content and is very similar to the MP4 file extension. M4V is supported exclusively by Apple devices. Other video formats like MP4 and MOV can be converted to M4V in order to run on Apple devices. The most common difference between the M4V and MP4 formats is that M4V offers DRM-Copyright Protection which prevents the copyright of media content. To play a DRM-protected M4V file the computer needs authorization by opening the iTunes account used for buying the media file. However, if the files are not protected by DRM, the user can just rename the file extension from M4V to MP4 in order for it to be recognized by non-apple devices.
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.