File with an ISMV extension contains video data in the Protected Interoperable File Format – (PIFF), based on MP4 but stored in smaller fragments, which makes it easier to stream with no distortions. It is a Microsoft standard utilised to provide multimedia data, for instance by the Smooth Streaming technology on a Microsoft IIS server.

ISMV files can be encrypted with Microsoft Expression Encoder application, while some can be converted into the original format or the MP4, with the mp4spli tool. The Smooth Streaming service enables transmission via HTTP protocol with a variable transfer, thus it can operate on many ISMV files with different image quality, dependant on the actual transfer speed.