Utdrag från http://en.wikipedia.org/wiki/Hd_Photo:
Licensing
Microsoft has patents on the technology in HD Photo. A Microsoft representative stated in a January 2007 interview that in order to encourage the adoption and use of HD Photo, the specification is made available under Microsoft's Open Specification Promise, which asserts that Microsoft offers the specification for free, and will not file suit on the patented technology, and that open-source software can therefore make use of the format.[2] However, as of Microsoft's February 15, 2007 update, HD Photo is still not among the technologies that Microsoft has listed as being covered by the Open Specification Promise.[3]
In addition to the specification itself, Microsoft released the "HD Photo Device Porting Kit" which provides source code and build configuration files for multiple platforms. While the license for this code is designed to encourage broad adoption in products, the license terms specifically prohibit including any of Device Porting Kit's code in products or systems that use strong copyleft licensing.[4]
“ 2. c. Distribution Restrictions. You may not ... modify or distribute the source code of any Distributable Code so that any part of it becomes subject to an Excluded License. An Excluded License is one that requires, as a condition of use, modification or distribution, that the code be disclosed or distributed in source code form; or others have the right to modify it. ”
As a consequence, any implementation that would be suitable for inclusion in a software package distributed under the GNU General Public License would need to be written from the HD Photo Bitstream Specification (also assuming Microsoft does cover HD Photo under the Open Specification Promise), although the licenses such as the Open Source Initiative-approved BSD license would likely be acceptable.