ASF (standing for Advanced Systems Format) is a proprietary Microsoft multimedia container format that features both audio and video data, with optional metadata.
ASF files may be compressed using several codecs, but they can also be played by numerous multimedia apps available today.
ASF players offer their users the option to create playlists using these files, and to integrate tracks of other formats for later playback.
Some of these apps may also enable users to quickly export their tracks to other file formats.