pdf The .pdf file format extension was developed by Adobe systems in 1993 as a means of presenting documents in a consistent manner across different platforms, hardware, operating systems, and applications. The format was not released as an open source document format until 2008, though minimal proprietary technologies still controlled by Adobe Systems exist in the format. Every .pdf document carries with it the necessary meta information required to properly reconstruct the text, fonts, and graphics used to produce the document. This ensures that documents will be viewed in exactly the same way the author intended regardless of the device used to open the document. From conception to date, Adobe Systems has continued to support the format adding features with every iteration of the standard including hardened algorithms for document encryption and privacy. Today, many freely available readers exist allowing you to open and view .pdf documents and create or convert other file formats such as .jpeg and .doc into .pdf documents.
mtv The .mtv filename extension is the second filename extension that refers to the proprietary video file format container AMV. AMV is a video container modified from the AVI video format and is primarily associated with video enabled Chinese portable MP4 players. Video stream files with either the .amv or .mtv filename extension can be played back on these devices. To maintain a relatively low cost, these MP4/MTV players rely on this video format and inexpensive hardware rather than more common but expensive proprietary video playback formats.