NSV (Nullsoft Streaming Video) is an audiovisual container format for streaming video data online. It was created in 2003 by Justin Frankel, while he was still working for Nullsoft. NSV only supports VP3 video codes and MP3 audio, although it was initially designed to stream all audio and video codecs. It is, in fact, the first format to allow users to make and stream live/recorded videos over the internet.
M4R is a filename extension for AAC format, which is developed by Apple Inc. It is typically used to save custom iPhone ringtones from Apple iTunes. M4R can only be created from iTunes purchased songs and is usually DRM protected. It can open on iTunes, VLC Media Player, Apple QuickTime Player, and more.