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Original commit message from CVS: * docs/faq/legal.xml: Update FAQ, Totem actually has an exception these days.
215 lines
6.9 KiB
XML
215 lines
6.9 KiB
XML
<sect1 id="chapter-legal">
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<title id="title-legal">GStreamer Legal Issues</title>
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<para>
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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 <ulink url="http://www.fsf.org/">
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FSF lawyers</ulink>, so we view them as the
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final interpretation on how the GPL and LGPL interact with patents in our
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opinion. This consultancy was paid for by
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<ulink url="http://www.fluendo.com/">Fluendo</ulink>
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in order to obtain clear and quotable answers. These answers were certified
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by the FSF lawyer team and verified by FSF lawyer and law professor Eben Moglen.
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</para>
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<qandaset defaultlabel="qanda">
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<qandaentry>
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<question id="legal-distribute-three">
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<para>
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Can someone distribute the combination of
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<itemizedlist>
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<listitem><para>GStreamer, the LGPL library</para></listitem>
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<listitem><para>MyPlayer, a GPL playback application</para></listitem>
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<listitem><para>The binary-only Sorenson decoder</para></listitem>
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</itemizedlist>
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together in one distribution/operating system ? If not, what
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needs to be changed to make this possible ?
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</para>
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</question>
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<answer>
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<para>
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This would be a problem, because the GStreamer and MyPlayer licenses would
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forbid it. In order to link GStreamer to MyPlayer, you need to use section
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3 of the LGPL to convert GStreamer to GPL. The GPL version of GStreamer
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forbids linking to the Sorenson decoder. Anyway, the MyPlayer GPL
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license forbids this.
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</para>
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<para>
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If the authors of MyPlayer want to permit this, we have an
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exception for them: the controlled interface exception from the FAQ.
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The idea of this is that you can't get around the GPL just by including
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a LGPL bit in the middle.
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</para>
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<para>
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Note: MyPlayer is a completely fictituous application at the time of writing.
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</para>
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</answer>
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</qandaentry>
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<qandaentry>
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<question id="legal-binary-plugin">
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<para>
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Suppose Apple wants to write a binary-only proprietary
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plugin for GStreamer to decode Sorenson video, which will be shipped
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stand-alone, not part of a package like in the question above.
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Can Apple distribute this binary-only plugin ?
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</para>
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</question>
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<answer>
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<para>
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Yes, modulo certain reverse engineering requirements in section 6 of
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the LGPL.
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</para>
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</answer>
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</qandaentry>
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<qandaentry>
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<question id="legal-gpl-program">
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<para>
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If a program released under the GPL uses a library that
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is LGPL, and this library can dlopen plug-ins at runtime, what are the
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requirements for the license of the plug-in ?
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</para>
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</question>
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<answer>
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<para>
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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 you
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that it would be safe to do so, but we also will not advise you that it
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would be absolutely forbidden.
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</para>
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</answer>
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</qandaentry>
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<qandaentry>
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<question id="legal-safe-countries">
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<para>
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Can someone in a country that does not have software patents distribute
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code covered by US patents under the GPL to people in, for example, Norway ?
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If he/she visits the US, can he/she be arrested ?
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</para>
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</question>
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<answer>
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<para>
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Yes, he can.
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No, there are no criminal penalties for patent infringement in the US.
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</para>
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</answer>
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</qandaentry>
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<qandaentry>
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<question id="legal-unsafe-countries">
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<para>
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Can someone from the US distribute software covered by
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US patents under the GPL to people in Norway ? To people in the US ?
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</para>
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</question>
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<answer>
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<para>
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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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</para>
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</answer>
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</qandaentry>
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<qandaentry>
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<question id="legal-gpl-library-patents">
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<para>
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There are a lot of GPL- or LGPL-licensed libraries that
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handle media codecs which have patents. Take mad, an mp3 decoding library,
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as an example. It is licensed under the GPL. In countries where patents
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are valid, does this invalidate the GPL license for this project ?
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</para>
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</question>
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<answer>
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<para>
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The mere existence of a patent which might read on the program does not
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change anything. However, if a court judgement or other agreement
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prevents you from distributing libmad under GPL terms, you can not
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distribute it at all.
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</para>
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<para>
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The GPL and LGPL say (sections 7 and 11):
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<quote>If you cannot distribute so as to satisfy simultaneously your
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obligations under this License and any other pertinent obligations, then
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as a consequence you may not distribute the Library at all.</quote>
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</para>
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</answer>
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</qandaentry>
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<qandaentry>
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<question id="legal-gpl-court-judgment">
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<para>
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So let's say there is a court judgement. Does this mean that the GPL license is
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invalid for the project everywhere, or only in the countries where it conflicts
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with the applicable patents ?
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</para>
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</question>
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<answer>
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<para>
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The GPL operates on a per-action, not per-program basis. That is, if
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you are in a country which has software patents, and a court tells you
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that you cannot distribute (say) libmad in source code form, then you
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cannot distribute libmad at all. This doesn't affect anyone else.
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</para>
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</answer>
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</qandaentry>
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<qandaentry>
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<question id="legal-gpl-and-binary">
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<para>
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Patented decoding can be implemented in GStreamer either by
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having a binary-only plugin do the decoding, or by writing a plugin
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(with any applicable license) that links to a binary-only library.
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Does this affect the licensing issues involved in regards to GPL/LGPL?
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</para>
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</question>
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<answer>
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<para>
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No.
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</para>
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</answer>
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</qandaentry>
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<qandaentry>
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<question id="legal-gpl-patent-distribution">
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<para>
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Is it correct that you cannot distribute the GPL mad library to
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decode mp3's, *even* in the case where you have obtained a valid license
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for decoding mp3 ?
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</para>
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</question>
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<answer>
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<para>
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The only GPL-compatible patent licenses are those which are open to
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all parties posessing copies of GPL software which practices the
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teachings of the patent.
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</para>
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<para>
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If you take a license which doesn't allow others to distribute
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original or modified versions of libmad practicing the same patent
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claims as the version you distribute, then you may not distribute at
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all.
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</para>
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</answer>
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</qandaentry>
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</qandaset>
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</sect1>
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