ASF is a multimedia container file format that specially designed for online video streaming. ASF is an abbreviation of Advanced Systems Format (formerly Advanced Streaming Format, Active Streaming Format). It's Microsoft's proprietary media format and a part of the Windows Media framework.

As a media container, ASF file can store video, audio, image and media data. This file format does not specify the codec of video or audio in it. The most common file types contained within an ASF file are Windows Media Audio (WMA) and Windows Media Video (WMV). ASF, WMV, WMA are often used interchangeably.

ASF is based on serialized objects which are essentially byte sequences optimized for streaming via the Internet. When you watch ASF video on web page, content is delivered to you as a continuous flow of data. You no longer have to wait for the audio and video files to fully download before you start to view them.

To stream ASF file online, you need to upload the ASF file to your web server, and embed the file on web page with Adobe Flash Player, so that users can control the playback of the video. ASF can also be used in live video streaming. You can use a video capture card to input the content recorded by video camcorder and microphone to computer, encode the content to ASF stream, and broadcast the content to the Internet.

If you want to convert video to ASF file, you can check this ASF Video Converter. It supports to convert between all the popular video and audio formats: ASF, AVI, DivX, Xvid, VOB, MOV, WMV, RMVB, RM, MPEG, FLV, MPG, MP4, MP3, WMA, 3GP, MKV, and so on.

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