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344 lines
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Markdown
344 lines
18 KiB
Markdown
---
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short-description: Patents, Licenses and legal F.A.Q.
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...
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# Legal information
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## Installer, default installation
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The installer (Microsoft Windows and MacOSX) and the default
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installation (GNU/Linux) contain and install the minimal default
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installation. At install time or later, the downloading of optional
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components is also possible, but read on for certain legal cautions you
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might want to take. All downloads are from the
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[gstreamer.freedesktop.org](http://gstreamer.freedesktop.org) website.
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## Licensing of GStreamer
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GStreamer minimal default installation only contains packages which
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are licensed under the [GNU LGPL license
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v2.1](http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html). This
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license gives you the Freedom to use, modify, make copies of the
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software either in the original or in a modified form, provided that the
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software you redistribute is licensed under the same licensing terms.
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This only extends to the software itself and modified versions of it,
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but you are free to link the LGPL software as a library used by other
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software under whichever license. In other words, it is a weak copyleft
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license.
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Therefore, it is possible to use GStreamer to build applications that are
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then distributed under a different license, including a proprietary one,
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provided that reverse engineering is not prohibited for debugging
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modifications purposes. Only the pieces of GStreamer that are under the
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LGPL need to be kept under the LGPL, and the corresponding source code
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must be distributed along with the application (or an irrevocable offer
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to do so for at least three years from distribution). Please consult
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section 6 of the
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[LGPL](http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html) for
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further details as to what the corresponding source code must contain.
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Some portions of the minimal default installation may be under
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different licenses, which are both more liberal than the LGPL (they are
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less strict conditions for granting the license) and compatible with the
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LGPL. This is advised locally.
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## Optional packages
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There are two types of optional packages (GPL and Patented), which are
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under a different license or have other issues concerning patentability
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(or both).
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#### GPL code
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Part of the optional packages are under the GNU GPL
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[v2](http://www.gnu.org/licenses/old-licenses/gpl-2.0.html). This means that
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you cannot link the GPL software in a program unless the same program is
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also under the GPL, but you are invited to seek competent advice on how
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this works in your precise case and design choices. GPL is called
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“strong copyleft” because the condition to distributed under the same
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license has the largest possible scope and extends to all derivative
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works.
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#### Patents
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Certain software, and in particular software that implements
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multimedia standard formats such as MP3, MPEG 2 video and audio, h.264,
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MPEG 4 audio and video, AC3, etc, can have patent issues. In certain
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countries patents are granted on software and even software-only
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solution are by and large considered patentable and are patented (such
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as in the United States). In certain others, patents on pure software
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solutions are formally prohibited, but granted (this is the case in many
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European countries), and in others again are neither allowed nor granted.
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It is up to you to make sure that in the countries where GStreamer is
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used, products are made using it and product are distributed, a license
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from the applicable patent holders is required or not. Receiving GStreamer
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– or links to other downloadable software – does not provide any license
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expressed or implied over these patents, except in very limited
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conditions where the license so provides. No representation is made.
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In certain cases, the optional packages are distributed only as source
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code. It is up to the receiver to make sure that in the applicable
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circumstances compiling the same code for a given platform or
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distributing the object code is not an act that infringes one or more
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patents.
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## Software is as-is
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All software and the entire GStreamer binaries are provided as-is, without any
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warranty whatsoever. The individual licenses have particular language
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disclaiming liability: we invite you to read all of them. Should you
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need a warranty on the fact that software works as intended or have any
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kind of indemnification, you have the option to subscribe a software
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maintenance agreement with a company or entity that is in that business.
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## Licensing of code contributed to GStreamer itself
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GStreamer is a plugin-based framework licensed under the LGPL. The
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reason for this choice in licensing is to ensure that everyone can use
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GStreamer to build applications using licenses of their choice.
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To keep this policy viable, the GStreamer community has made a few licensing
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rules for code to be included in GStreamer's core or GStreamer's
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official modules, like our plugin packages.
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**We require that all code going into our core packages is LGPL.**
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For the plugin code, we require the <B>use of the LGPL for all plugins
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written from scratch or linking to external libraries</B>. The only
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exception to this is when plugins contain older code under the BSD and
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MIT license. They can use those licenses instead and will still be
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considered for inclusion, we do prefer that all new code written
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though is at least dual licensed LGPL. We do not accept GPL code to be
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added to our plugins modules, but we do accept LGPL-licensed plugins
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using an external GPL library for some of our plugin modules. The
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reason we demand plugins be licensed under the LGPL, even when they
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are using a GPL library, is that other developers might want to use
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the plugin code as a template for plugins linking to non-GPL
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libraries. We also accept dual licensed plugins for inclusion as long
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as one of the licenses offered for dual licensing is the LGPL.
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We also do not allow plugins under any license into our core,base
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or good packages if they have known patent issues associated with
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them. This means that even a contributed LGPL/MIT licensed
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implementation of something which there is a licensing body claiming
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fees for, those plugins would need to go into our gst-plugins-ugly
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module.
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All new plugins, regardless of licensing or patents
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tend to have to go through a period in our incubation module,
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gst-plugins-bad before moving to ugly, base or good.
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## Frequently Asked Questions
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#### What licenses are there?
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GStreamer binaries contain software under various licenses. See above.
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#### How does this relate to the packaging system?
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The packaging is only a more convenient way to install software and
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decide what's good for you. GStreamer is meant to be modular, making use
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of different modules, or plugins, that perform different activities.
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We provide some of them by default. Others are provided as an additional
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download, should you elect to do so. You could do the same by finding
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and downloading the same packages for your own platform. So it is
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entirely up to you to decide what to do.
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Also, we note that GStreamer elements are divided into different packages,
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roughly following the licensing conditions attached to the same. For
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instance, the codecs-gpl package contains GPL licensed codecs. All the
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packages installed by default, conversely, are licensed under the LGPL
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or a more liberal license. This division is provided only for ease of
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reference, but we cannot guarantee that our selection is 100% correct,
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so it is up to the user to verify the actual licensing conditions before
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distributing works that utilize GStreamer.
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#### Can I / must I distribute GStreamer along with my application?
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You surely can. All software is Free/Open Source software, and can be
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distributed freely. You are not **required** to distribute it. Only,
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be reminded that one of the conditions for you to use software under
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certain licenses to make a work containing such software, is that you
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also distribute the complete source code of the original code (or of
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the modified code, if you have modified it). There are alternative
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ways to comply with this obligation, some of them do not require any
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actual distribution of source code, but since GStreamer contains the
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entire source code, you might want to include it (or the directories
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containing the source code) with your application as a safe way to
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comply with this requirement of the license.
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#### What happens when I modify the GStreamer's source code?
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You are invited to do so, as the licenses (unless you are dealing with
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proprietary bits, but in that case you will not find the corresponding
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source code) so permit. Be reminded though that in that case you need
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to also provide the complete corresponding source code (and to
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preserve the same license, of course). You might also consider to push
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your modifications upstream, so that they are merged into the main
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branch of development if they are worth it and will be maintained by
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the GStreamer project and not by you individually. We invite you not
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to fork the code, if at all possible. The Cerbero build system has a
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"bundle-source" command that can help you create a source bundle
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containing all of the complete corresponding machine readable source
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code that you are required to provide.
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#### How does licensing relate to software patents? What about software patents in general?
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This is a tricky question. We believe software patents should not exist,
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so that by distributing and using software on a general purpose machine
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you would not violate any of them. But the inconvenient truth is that
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they do exist.
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Software patents are widely available in the USA. Even though they are
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formally prohibited in the European Union, they indeed are granted by
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the thousand by the European Patent Office, and also some national
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patent offices follow the same path. In other countries they are not
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available.
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Since patent protection is a national state-granted monopoly,
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distributing software that violates patents in a given country could be
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entirely safe if done in another country. Fair use exceptions also
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exist. So we cannot advise you whether the software we provide would be
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considered violating patents in your country or in any other country,
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but that can be said for virtually all kinds of software. Only, since we
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deal with audio-video standards, and these standards are by and large
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designed to use certain patented technologies, it is common wisdom that
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the pieces of software that implement these standards are sensitive in
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this respect.
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This is why GStreamer has taken a modular approach, so that you can use
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a Free plugins or a proprietary, patent royalty bearing, plugin for a
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given standard.
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#### What about static vs. dynamic linking and copyleft?
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We cannot provide one single answer to that question. Since copyright in
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software works as copyright in literature, static linking means
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basically that the programmer includes bits of code of the original
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library in the bytecode at compile time. This amounts to make derivative
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code of the library without conceivable exceptions, so you need a
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permission from the copyright holders of the library to do this.
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A widespread line of thinking says that dynamic linking is conversely
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not relevant to the copyleft effect, since the mingling of code in a
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larger work is done at runtime. However, another equally authoritative
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line of thought says that only certain type of dynamic linking is not
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copyright relevant. Therefore, using a library that is specifically
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designed to be loaded into a particular kind of software, even through
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API, requires permission by the copyright holder of the library when
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the two pieces are distributed together.
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In all cases, since most of the software we include in GStreamer is under
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the LGPL, this permission is granted once for all, subject to compliance
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with the conditions set out by it. Therefore, the problem only arises
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when you want to use GPL libraries to make non-GPL applications, and you
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need to audit your software in that case to make sure that what you do
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is not an infringement. This is why we have put the GPL libraries in a
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separate set of optional components, so you have a clearer view of what
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is safely clear for use, and what might need better investigation on a
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case-by-case basis.
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Please be reminded that even for LGPL, the recipient of the software
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must be in a position to replace the current library with a modified
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one, and to that effect some conditions apply, among which that for
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static linking you must also provide the complete toolchain required to
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relink the library (“any data and utility programs needed for
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reproducing the executable from it”, except the “major components”) and
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that the license of the conditions of the resulting program must allow
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decompilation to debug modifications to the library.
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## Licensing applications under the GNU GPL using GStreamer
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The licensing of GStreamer is no different from a lot of other libraries out
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there like GTK+ or glibc:
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we use the [LGPL](http://www.fsf.org/licenses/lgpl.html).
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What complicates things with regards to GStreamer is its plugin-based design
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and the heavily patented and proprietary nature of many multimedia codecs.
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While patents on software are currently only allowed in a small minority of
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world countries (the US and Australia being the most important of those), the
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problem is that due to the central place the US hold in the world economy and
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the computing industry, software patents are hard to ignore wherever you are.
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Due to this situation, many companies, including major GNU/Linux distributions,
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get trapped in a situation where they either get bad reviews due to lacking
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out-of-the-box media playback capabilities (and attempts to educate the
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reviewers have met with little success so far), or go against their
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own - and the free software movement's - wish to avoid proprietary software.
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Due to competitive pressure, most choose to add some support. Doing that
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through pure free software solutions would have them risk heavy litigation and
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punishment from patent owners. So when the decision is made to include support
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for patented codecs, it leaves them the choice of either using special
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proprietary applications, or try to integrate the support for these codecs
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through proprietary plugins into the multimedia infrastructure provided by
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GStreamer. Faced with one of these two evils the GStreamer community of
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course prefer the second option.
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The problem which arises is that most free software and open source
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applications developed use the GPL as their license. While this is generally a
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good thing, it creates a dilemma for people who want to put together a
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distribution. The dilemma they face is that if they include proprietary
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plugins in GStreamer to support patented formats in a way that is legal for
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them, they do risk running afoul of the GPL license of the applications. We
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have gotten some conflicting reports from lawyers on whether this is actually a
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problem, but the official stance of the FSF is that it is a problem.
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We view the FSF as an authority on this matter, so we are inclined to follow
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their interpretation of the GPL license.
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So what does this mean for you as an application developer? Well, it
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means **you have to make an active decision on whether you want your
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application to be used together with proprietary plugins or
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not**. What you decide here will also influence the chances of
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commercial distributions and Unix vendors shipping your
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application. The GStreamer community suggest you license your software
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using a license that will allow non-free, patent implementing or
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non-GPL compatible plugins to be bundled with GStreamer and your
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applications, in order to make sure that as many vendors as possible
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go with GStreamer instead of less free solutions. This in turn we
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hope and think will let GStreamer be a vehicle for wider use of free
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formats like the [Xiph.org](http://www.xiph.org/) formats.
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If you do decide that you want to allow for non-free plugins to be used with
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your application you have a variety of choices. One of the simplest is using
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licenses like LGPL, MPL or BSD for your application instead of the GPL.
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Or you can add a exceptions clause to your GPL license stating that you except
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GStreamer plugins from the obligations of the GPL.
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A good example of such a GPL exception clause would be, using the Totem
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video player project as an example:
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*The developers of the Totem video player hereby grants permission for
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non-GPL compatible GStreamer plugins to be used and distributed together
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with GStreamer and Totem. This permission is above and beyond the permissions
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granted by the GPL license by which Totem is covered. If you modify this code,
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you may extend this exception to your version of the code, but you are
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not obligated to do so. If you do not wish to do so, delete this exception
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statement from your version.*
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Our suggestion among these choices is to use the LGPL license, as it is what
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resembles the GPL most and it makes it a good licensing fit with the major
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GNU/Linux desktop projects like GNOME and KDE. It also allows you to share
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code more openly with projects that have compatible licenses. As you might
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deduce, pure GPL licensed code without the above-mentioned clause is not
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re-usable in your application under a GPL plus exception clause unless you
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get the author of the pure GPL code to allow a relicensing to GPL plus
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exception clause. By choosing the LGPL, there is no need for an exception
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clause and thus code can be shared freely between your application and
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other LGPL using projects.
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We have above outlined the practical reasons for why the GStreamer community
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suggest you allow non-free plugins to be used with your applications. We feel
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that in the multimedia arena, the free software community is still not strong
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enough to set the agenda and that blocking non-free plugins to be used in our
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infrastructure hurts us more than it hurts the patent owners and their ilk.
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This view is not shared by everyone.
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The [Free Software Foundation](http://www.fsf.org) urges you to use
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an unmodified GPL for your applications, so as to push back against the
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temptation to use non-free plug-ins. They say that since not everyone else has
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the strength to reject them because they are unethical, they ask your help to
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give them a legal reason to do so.
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