ASF stands for Advanced Streaming Format.
ASF is a highly compressed file format that contains streaming video, audio. When an ASF file is palyed back, content is deliverd to you as a continuous flow of data. You no longer have to wait for the whole video and audio file to fully download before you start to view them. So, this file format is specially designed to run on networks. When an AVI file is compressed and converted to an .asf file, the file begins playing after only a few seconds. ASF files can be played back with the Windows Media Player (provided the appropriate codecs are installed), streamed with Windows Media Services or optionally packaged with Windows Media Rights Manager. You can click here to find more information about ASF format.
Advanced Streaming Format (or ASF, later renamed into Advanced Systems Format) is Microsoft's proprietary digital audio/digital video container format, especially meant for streaming. ASF is part of the Windows Media framework.
The format does not specify how the video or audio should be encoded, but instead just specifies the structure of the video/audio stream. What this means is that ASF files can be encoded with basically any audio/video codec and still would be in ASF format. This is similar to the function performed by the QuickTime format or the Ogg format.
The ASF format is based on serialized objects which are essentially byte-sequences identified by a GUID marker.
The most common filetypes contained within an ASF file are Windows Media Audio (WMA) and Windows Media Video (WMV).
ASF files can also contain objects representing metadata, such as the artist, title, album and genre for an audio track, or the director of a video track, much like the ID3 tags of MP3 files.
ASF files containing only WMA audio can be named with the filename extension .wma and files of only audio and video content may have the extension .wmv. Both may use the .asf extension if desired.
ASF is often confused with Microsoft's own implementation of MPEG-4 video format (Windows Media Video), because most of the ASF streams are encoded using this technology.
The ASF container structure is patented in the United States (United States Patent 6,041,345 Levi, et al. March 21, 2000) by Microsoft and Microsoft has invoked its patent against VirtualDub, a free video conversion program. Interestingly, Apple's iTunes software now has the capability to convert WMA files to AAC.
View how to convert ASF to AVI, MPEG, WMV, VCD, DVD.