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.
jpg The .jpg filename extension refers to digital photography files or digital images that are associated with the JPEG file format specification. The joint photographic experts group, or JPEG for short, is a file format from the 'lossy image' class of image formats. Many devices including smartphones with inbuilt cameras and professional digital SLR cameras support the JPEG/Exif file format natively. Such support allow images captured on these devices to be stored directly into the jpg format without conversion. Efforts towards standardization of the JPEG format first begun in 1992 with ISO/IEC 10918-1:1994