WHAT IS ASF?
ASF (Advanced Systems Format) was created by Microsoft with the primary objective of supporting HTTP and media server playback. If you are not sure how to play an ASF file, you’ll find information about the ASF format specification and a list of programs that can help you open media of this file type below.
An ASF file can contain multiple audio and video streams and be encoded with various codecs. The ASF file type is most often used for streaming media. An ASF file can also include metadata, text, and web pages.
Windows Media Player, CyberLink PowerDVD, the VLC media player, Winamp