ASF and WMV Files

As we all know, WMV file and ASF file are all the video format devolped by Microsoft. The difference between them? That are the file extensions and the MIME types. The MIME type for a WMV file is video/x-ms-wmv and the MIME type for ASF is video/x-ms-asf. The basic internal structure of the files is identical.

The Advanced Systems Format (ASF) is the preferred Windows Media file format. With Windows Media Player, if the appropriate codecs are installed on your computer, you can play audio content, video content, or both, that is compressed with a wide variety of codecs and that is stored in an .asf file. Additionally, you can stream audio and video content with Windows Media Services, or you can package that content with Windows Media Rights Manager.

ASF is an extensible file format that stores synchronized multimedia data. It supports data delivery over a wide variety of networks and protocols. It is also suitable for local playback. ASF supports advanced multimedia capabilities including extensible media types, component download, scalable media types, author-specified stream prioritization, multiple language support, and extensive bibliographic capabilities that include document and content management.

Typically, ASF files that contain audio content that is compressed with the Windows Media Audio (WMA) codec use the .wma extension. Similarly, ASF files that contain audio content, video content, or both, that is compressed with Windows Media Audio (WMA) and Windows Media Video (WMV) codecs use the .wmv extension. Finally, content that is compressed with any other codec use the generic .asf extension.

Windows Media Video (.wmv) files are Advanced Systems Format (.asf) files that include audio, video, or both compressed with Windows Media Audio (WMA) and Windows Media Video (WMV) codecs. By using a separate extension, you can install multiple players on your computer and associate certain players with the .wmv extension for playback of audio and video sources.


Ususally, the change in extensions was made to make it easier for an application to identify the content of a media file. A .wmv extension show the file containing both video and audio and it can be applied to APPLIES Microsoft Windows Media Services 4.1, Microsoft Windows Media Encoder 7.0 and Microsoft Windows Media Encoder 7.1. There are many chances for people to get access to WMV files, however, its file size bigger than FLV and sometimes we need to convert WMV to FLV to share our videos online or broadcast them.