ASF file format
VLC Media Player
Windows Media Player
The Advanced System file is a media file used by Microsoft Window Media Player for streaming online audio and video files. The media container determines the data stream structure but not data encoding. So, the files encoded by Microsoft developers contain the .wmv or .wma extensions while other files have .asf extension. The ASF has a MIME type that allows files to be sent via the internet. Therefore, it can play audio and video directly while downloading data online.
The .asf file comes with audio, video, and metadata just the same as the MP3. It defines the album, artists, and so on. Using this file, streaming can be done in a similar way to other formats. This makes user access to the file once some bytes have been downloaded while the downloading continues and the user watches. However, it has a maximum resolution of 352×288, which is adjudged small because it is designed for streaming.