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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 contents of an ASF file is:
ASF files can also contain objects representing metadataMetadata is data about data. An example is a library catalog card, which contains data about the nature and location of a book: It is data about the data in the book referred to by the card. The content combined with its metadata is often called a content, such as the artist, title, album and genre for an audio track, or the director of a video track, much like the ID3This article is about the metadata format for MP3 files. For information about the machine learning algorithm which produces decision trees, see Inductive Dichotomiser 3 (ID3). ID3 is a tagging format for MP3s. It allows metadata such as the title, artist tags of MP3MP3 (or, more precisely, MPEG-1/2 Audio Layer 3 is an audio compression algorithm capable of greatly reducing the amount of data required to reproduce audio, while sounding like a faithful reproduction of the original uncompressed audio to the listener. files.
ASF files containing only WMA audio can be named with the file suffix .wma and files of only audio and video content may have the suffix .wmv. Both may use .asf as a suffix if desired.
ASF is often confused with Microsoft's own implementation of MPEG-4MPEG-4 introduced in 1998, is the designation for a group of audio and video coding standards agreed upon by MPEG (Moving Picture Experts Group). MPEG-4 is primarily designed to handle low bit rate content, from 4800 bit/s to approximately 4 Mbit/s. The p video format ( Windows Media VideoWindows Media Video WMV is a generic name for the set of streaming video technologies developed by Microsoft. It is part of the Windows Media framework. WMV is not built solely on Microsoft in-house technology. From version 7 (WMV7), Microsoft has used it), because most of the ASF streams are encoded using this technology.
The ASF structure (the container, not some codec algorithm) 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 VirtualDubVirtualDub is an open source video capture and linear processing tool for Microsoft Windows. It is written by Avery Lee, and is licensed under the GPL. It is hosted on SourceForge and is at version 1. It features many advanced features as well as being ab, a free video conversion program, which wasn't even marketed. The reason why they invoked the patent was the control over the content which they have without other programs being able to read ASF.