Advanced Systems Format, or ASF, is a digital video or digital audio container format which is used for streaming media files. Media files can be made up of video content or audio content or both.
This format was developed by Microsoft which holds proprietary rights over it. Currently, Advanced Systems Format (ASF) is an integral part of the Windows Media module.
It is a highly compressed and very flexible format that is used to contain streaming video, audio, pictures and slide shows. An ASF file format makes it possible to deliver content to a user in a continuous and uninterrupted manner so that data may flow to the user in less time and it may reach to the user before the playback starts.
Some other formats of file which are very similar to ASF are AVI, QuickTime, and Ogg file formats.
ASF also supports the use of metadata. For example, information about the title, artist, genre and album of an audio file, or the director and actors of a video file can be stored in an ASF file. This is similar to ID3 tags used with MP3 files. Furthermore, it supports both on-demand and live multimedia content.
Increasingly this is being replaced by newer file formats which achieve significant compression without being “lossy” – i.e. no quality is lost in the compression process.