Free software projects harmed by software patents
The following are sources of information about free software projects harmed by software patents. Most of this harm comes as passive threats.
IBM has claimed that software patents help free software. (See Fake representatives of free software#IBM) This page collects that evidence that this is obviously untrue and isn't a position shared by free software developers or users.
Products that have had to remove features
- VirtualDub (also: German original: OSS video without ASF (English translations[?]: Google, bing translator))
- The photo-mosaic plugin for the GNU Image Manipulation Program
- Red Hat removes "fill series" functionality from OpenOffice.org spreadsheets
- Linux patch to the VFAT filesystem to avoid the patent Microsoft asserted against TomTom (See also: Microsoft FAT patents)
- BZip2, or actually BZip1 which was based on Arithmetic coding. Had to be canceled due to patents on Arithmetic Coding for compression algorithms.
- BZip2 is based on Huffman encoding instead (either one had the Burrows-Wheeler transform)
- GZip/zlib's documentation notes that various methods had to be avoided due to compression patents.
- PostgreSQL had trouble with Adaptive Replacement Cache algorithm patented by IBM
- LLVM removed an implementation of Steensgaard's algorithm due to patent concerns. More details on the linked page.
- Blender has to be careful about packaging ffmpeg internally due to video codec patents
- Miro does not include support for patented codecs
- sipXecs Open Source IP PBX does not include support for MP3 voicemail files due to patents on MP3 encoding and decoding.
- Freeswitch Telephony Platform does not support the G.729 audio VoIP codec due to software encoding/decoding patent licensing fees to various agencies.
- The Hugin software (which combining overlapping photos to make continuous panoramas) includes code for automatically lining up the overlapping parts of the given photos, but this code is disabled in the USA versions because that algorithm (called "SIFT") is patented in the USA. A possible replacement algorithm, called SURF, is also patented and therefore left out. more info
- For patent reasons, Fedora's GNU/Linux distribution excludes:
- Android "Caller ID" app killed
-  Novell removed ppmtompeg (a MPEG-1 video encoder) from their netpbm package.
- The ZFS filesystem
- The FreeType fonts system - until July 2010, they had to leave features disabled due to Apple patents.
- freeSWITCH (SIP) and Asterisk PBS can't encode/decode "G279"  (see: G.729, G.722, and G.723.1)
- Fedora and OpenSUSE removed ppmtompeg, a MPEG-1 video encoder based on the Berkeley mpeg_encoder program from netpbm.
Litigation, threats, and uncertainty
- FireStar Software has filed a patent infringement suit against Red Hat, claiming that Hibernate infringes US Patent 6,101,502
- VideoLan and related projects are threatened
- Freetype fonts: Freetype & Patents
- The Doom3 engine will almost certainly become free software, but may have problems with patent claims by Creative when it does
- Microsoft's implication that Linux infringes their patents: 
- Ffmpeg and derivative products (mplayer, vlc, ffdshow, etc..) have to worry about video and audio codec patents
- Ogg Theora: wasn't included in the HTML 5 specification due to Apple expressing concerns over patent issues  (See also: HTML5 and video patents)
- XML-based word processors could be susceptible to the patents used in i4i v. Microsoft (Note: i4i inc. has confirmed that OpenOffice.org does not infringe their patents)
- ClamAV: In January 2008, Trend Micro accused Barracuda Networks of patent infringement for distribution of the ClamAV anti-virus software.  (See: Trend Micro v. Barracuda (2008, USA))
- JMRI sued KAM Industries for copyright infringement and for a declaratory judgment of the invalidity of patents owned by KAM. After years of litigation, KAM disclaimed one patent to avoid sanctions, but continues to press others.
- Cards911 Project The Cards 911 Project was an open source emergency medical call-taking system. The project consisted of a document that had a list of questions that would be used by 9-1-1 call takers. The call taker would determine the nature of the illness/injury and then be able to offer additional first aid instructions. The project was simply a document with hyperlinks. It was available in both OpenDocument (odt) and Adobe Acrobat (pdf) formats. The project was forced to shut down due to legal threats (violation of several patents) by Medical Priority Consultants. See also article on TechDirt. The offending document is available outside the United States through WikiLeaks. An Adobe Acrobat version of the Cease and Desist letter from Stoel Rives Attorneys at Law on behalf of Medical Priority Consultants of Salt Lake City, Utah is available here.
- GCC (and hence projects that are using GCC such as MingW, WINE and ReactOS) are unable to implement or use exception handling that is binary compatible with the Windows exception handling due to a borland patent on SEH. Article here Article is about WINE but this applies to anyone using GCC to work with win32 (or win32-clone) code who needs win32-compatible exception handling. The patent (http://www.google.com/patents/US5628016) expired on June, 15th 2014, however, so it should not any longer impede incorporation into OSS.
- Google Chrome implemented binary diff algorithm optimized for compiled executables called Courgette. It was sued for software patent violation. 
- Twolame, a MPEG-1 layer 2 audio encoder is not included in Fedora because of patent uncertainty.
- Mono - a Microsoft-supported free software project by Novell
- The ZFS file system, see: NetApp v. Sun (2008, USA)
Statements from project representatives
- Chris Blizzard, Mozilla's chief innovation officer "software patents reduce innovation"
Related pages on ESP Wiki
- Free software distributors paying patent tax
- Vulnerable free software with shielded binaries
- Standards harmed by patents
- Litigation and specific patents
- passive threats