If a non commercial or open source project uses a technique which some can argue is covered by a particular patent, what would be implications be. Do you have to pay royalties. If project does not generate any money what would be the effect? Also what is the best way to get use of the license while being open source? What is the implication of using a patent and being open source? The patent relates to a closed source project.
When an invention is patented, the patent owner has exclusive rights to use that invention for the duration of the patent term, within the jurisdiction where the patent was issued. In general, there isn't any special exception for non-commercial usage. However, patent law is a national affair, and there might be such rules in some countries.
Open-source projects cannot use patented techniques unless the patent owner issues them a royalty-free license. If there were a per-copy royalty fee, you would no longer be free to distribute copies of the open-source project, or to distribute your modifications. If software has such restrictions, it can't be considered open source software. Additionally, open source software must be free for any kind of usage. If a software may only be used for non-commercial purposes, that doesn't meet the open source definition.
Many modern open source licenses (GPLv2, GPLv3, Apache License 2.0) include an automatic patent grant, though they differ in some important details, e.g. what happens when the patented technique is only patented in some countries but not in others. What is an automatic patent grant? If I own a patent and create a software that uses this patent and license the software under one of those licenses, I automatically grant all users of this software the necessary patent licenses.
Unfortunately, some licenses like the MIT license do not have such a patent grant. If I own a patent and create a software that uses this patent and license that software under the MIT license, I could later sue the users of this software for a patent violation. MIT-licensed software therefore has a higher risk for users than other licenses.
Of course, the other licenses do not guarantee that the software is patent-free. If I create a software and publish it as open-source, and it later turns out that it relies on patents from someone else (even if I didn't know about the patent and invented the patented technique independently), then the software can no longer be used and I am probably liable for patent infringement.
If it is clear from the onset that a software relies on patents and the patent owner will not grant a free license, then the only way is to wait the 20 years until the patent expires.
I like to think of a patent is a time-limited monopoly granted for the usage of some patented "idea".
When an open source projects produces code that implements some patented stuff, there is no usage involved yet. For instance, FFmpeg may implement some patented media codecs, but you only "infringe" on the patents if you use these codecs... e.g. the code in of itself is not "infringing" at rest, only when you run it.
Also there is no such as fair use of this monopoly: the patent holder has exclusive rights, and the fact that you do not make money out of it has no bearing AFAIK.
So the net effect is that any users of your code may need to acquire a patent license of sorts for using your code. What it entails is going to be very specific for each patent.