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Advogato: Microsoft patents ASF media file format, stops reverse engineering

Jun 07, 2000, 02:17 (32 Talkback[s])
(Other stories by atai)

"Microsoft patents the ASF media file format and stops the author of VirtualDub, a GPLed video capture and processing program for Windows, from supporting ASF since he reverse-engineered the ASF file spec. The consequences are numerous: Third parties cannot develop their own tools to decode ASF or convert ASF to other formats, and if ASF becomes the dominate media format on the Internet (due to Microsoft's proprietary but high-quality MPEG4 codec and strong marketing), Microsoft gains de facto technical control over the creation and distribution of digital media. And if patenting file formats becomes a common practice, it can have a chilling effect on free software development since the reading/writing of data in popular formats (say, Microsoft Word files or MPEG4 video) would be prohibited, unless one uses designated drivers."

"...We're not talking about a codec problem here. Microsoft claims patent protection on the file format. Remember these implications the next time you consider ASF for your content:"

"A broken ASF file not accepted by the Microsoft parser would be lost; the patent would prevent anyone from writing a byte-level tool to recover the ASF file. A third-party Linux player wouldn't be legal, since there would be no way to legally extract the file data, even if third-party video and audio decoders were available. Attempting to transcode a compressed ASF to another format would be impossible with any Microsoft-licensed tools, even if you have the permission of the copyright owner, or even if you are the copyright owner, because the Windows Media Format SDK license requires programs to actively block this action. For instance, Microsoft compelled Nullsoft to disable DSP plugin support in WinAmp with Windows Media Audio content because the DSP interface could be used to transcode, even though DSP plugins normally just process the audio."

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