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.
wbmp .wbmp refers to the wireless application protocol bitmap monochrome graphics file format. The format was initially developed by the WAP forum which later become part of the open mobile alliance. WBMP files are optimized for mobile devices prior to the advent of smartphones and is categorized as a raster image file format. Mobile network services such as SMS and MMS on GSM carriers typically have compatible support for this format, allowing users to send graphics saved in this format.