Where is the m4v video used on? I mean in which software I can play. And how to convert it to mp4 or avi and so on.
.m4v is a H254 codec with a different container and is mainly used by Apple devices like iPhones / iPads as a video playback format. Any basic video convertor software can convert .m4v files to something else. You can use “Any Video Convertor” software for Windows and Mac, “Adobe Media Encoder” [Win / Mac], “Compressor” [Mac], “Freemake Video Convertor” [Windows]
M4V file format is generally used by iPhone, iPod, PlayStation Portable, etc. It is used as the default video conversion format in the software HandBrake and Air Video Server dwelled on Macintosh. You can use AVI video converter - convert your videos to AVI.