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112 lines
5 KiB
Markdown
112 lines
5 KiB
Markdown
# GStreamer Legal Issues
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<!-- FIXME: this entire section seems out of date and a bit weird. No one
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ever asks questions like that any more. Should be made more relevant -->
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This part of the FAQ is based on a series of questions we asked the FSF
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to understand how the GPL works and how patents affects the GPL. These
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questions were answered by the [FSF lawyers](http://www.fsf.org/), so we
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view them as the final interpretation on how the GPL and LGPL interact
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with patents in our opinion. This consultancy was paid for by
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[Fluendo](http://www.fluendo.com/) in order to obtain clear and quotable
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answers. These answers were certified by the FSF lawyer team and
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verified by FSF lawyer and law professor Eben Moglen.
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> Can someone distribute the combination of:
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> - GStreamer, the LGPL library
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> - MyPlayer, a GPL playback application
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> - The binary-only Sorenson decoder
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>
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> together in one distribution/operating system? If not, what needs to be
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> changed to make this possible?
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This would be a problem, because the GStreamer and MyPlayer
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licenses would forbid it. In order to link GStreamer to MyPlayer, you
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need to use section 3 of the LGPL to convert GStreamer to GPL. The GPL
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version of GStreamer forbids linking to the Sorenson decoder. Anyway,
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the MyPlayer GPL license forbids this.
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If the authors of MyPlayer want to permit this, we have an exception for
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them: the controlled interface exception from the FAQ. The idea of this
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is that you can't get around the GPL just by including a LGPL bit in the
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middle.
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Note: MyPlayer is a completely fictituous application at the time of
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writing.
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> Suppose Apple wants to write a binary-only proprietary plugin for GStreamer
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>
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> .. to decode Sorenson video, which will be shipped stand-alone,
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> not part of a package like in the question above. Can Apple distribute
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> this binary-only plugin?
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Yes, modulo certain reverse engineering requirements in section 6
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of the LGPL.
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> If a program released under the GPL uses a library that is LGPL, and
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> this library can dlopen plug-ins at runtime, what are the requirements
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> for the license of the plug-in?
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You may not distribute the plug-in with the GPL application.
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Distributing the plug-in alone, with the knowledge that it will be used
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primarily by GPL software is a bit of an edge case. We will not advise
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you that it would be safe to do so, but we also will not advise you that
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it would be absolutely forbidden.
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> Can someone in a country that does not have software patents
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> distribute code covered by US patents under the GPL to people in, for
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> example, Norway? If he/she visits the US, can he/she be arrested?
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Yes, he can. No, there are no criminal penalties for patent
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infringement in the US.
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> Can someone from the US distribute software covered by US patents
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> under the GPL to people in Norway? To people in the US?
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This might infringe some patents, but the GPL would not forbid it
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absent some actual restriction, such as a court judgement or agreement.
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The US government is empowered to refuse importation of patent
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infringing devices, including software.
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> There are a lot of GPL- or LGPL-licensed libraries that handle media
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> codecs which have patents. Take mad, an mp3 decoding library, as an
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> example. It is licensed under the GPL. In countries where patents are
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> valid, does this invalidate the GPL license for this project?
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The mere existence of a patent which might read on the program
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does not change anything. However, if a court judgement or other
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agreement prevents you from distributing libmad under GPL terms, you can
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not distribute it at all.
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The GPL and LGPL say (sections 7 and 11): “If you cannot distribute so
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as to satisfy simultaneously your obligations under this License and any
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other pertinent obligations, then as a consequence you may not
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distribute the Library at all.”
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> So let's say there is a court judgement. Does this mean that the GPL
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> license is invalid for the project everywhere, or only in the
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> countries where it conflicts with the applicable patents?
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The GPL operates on a per-action, not per-program basis. That is,
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if you are in a country which has software patents, and a court tells
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you that you cannot distribute (say) libmad in source code form, then
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you cannot distribute libmad at all. This doesn't affect anyone else.
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> Patented decoding can be implemented in GStreamer either by having a
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> binary-only plugin do the decoding, or by writing a plugin (with any
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> applicable license) that links to a binary-only library. Does this
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> affect the licensing issues involved in regards to GPL/LGPL?
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No.
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> Is it correct that you cannot distribute the GPL mad library to decode
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> mp3's, *even* in the case where you have obtained a valid license for
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> decoding mp3?
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The only GPL-compatible patent licenses are those which are open
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to all parties posessing copies of GPL software which practices the
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teachings of the patent.
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If you take a license which doesn't allow others to distribute original
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or modified versions of libmad practicing the same patent claims as the
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version you distribute, then you may not distribute at all.
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