“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.”