mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-11-27 04:01:08 +00:00
344 lines
18 KiB
Markdown
344 lines
18 KiB
Markdown
---
|
||
short-description: Patents, Licenses and legal F.A.Q.
|
||
...
|
||
|
||
# Legal information
|
||
|
||
## Installer, default installation
|
||
|
||
The installer (Microsoft Windows and MacOSX) and the default
|
||
installation (GNU/Linux) contain and install the minimal default
|
||
installation. At install time or later, the downloading of optional
|
||
components is also possible, but read on for certain legal cautions you
|
||
might want to take. All downloads are from the
|
||
[gstreamer.freedesktop.org](http://gstreamer.freedesktop.org) website.
|
||
|
||
## Licensing of GStreamer
|
||
|
||
GStreamer minimal default installation only contains packages which
|
||
are licensed under the [GNU LGPL license
|
||
v2.1](http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html). This
|
||
license gives you the Freedom to use, modify, make copies of the
|
||
software either in the original or in a modified form, provided that the
|
||
software you redistribute is licensed under the same licensing terms.
|
||
This only extends to the software itself and modified versions of it,
|
||
but you are free to link the LGPL software as a library used by other
|
||
software under whichever license. In other words, it is a weak copyleft
|
||
license.
|
||
|
||
Therefore, it is possible to use GStreamer to build applications that are
|
||
then distributed under a different license, including a proprietary one,
|
||
provided that reverse engineering is not prohibited for debugging
|
||
modifications purposes. Only the pieces of GStreamer that are under the
|
||
LGPL need to be kept under the LGPL, and the corresponding source code
|
||
must be distributed along with the application (or an irrevocable offer
|
||
to do so for at least three years from distribution). Please consult
|
||
section 6 of the
|
||
[LGPL](http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html) for
|
||
further details as to what the corresponding source code must contain.
|
||
|
||
Some portions of the minimal default installation may be under
|
||
different licenses, which are both more liberal than the LGPL (they are
|
||
less strict conditions for granting the license) and compatible with the
|
||
LGPL. This is advised locally.
|
||
|
||
## Optional packages
|
||
|
||
There are two types of optional packages (GPL and Patented), which are
|
||
under a different license or have other issues concerning patentability
|
||
(or both).
|
||
|
||
#### GPL code
|
||
|
||
Part of the optional packages are under the GNU GPL
|
||
[v2](http://www.gnu.org/licenses/old-licenses/gpl-2.0.html). This means that
|
||
you cannot link the GPL software in a program unless the same program is
|
||
also under the GPL, but you are invited to seek competent advice on how
|
||
this works in your precise case and design choices. GPL is called
|
||
“strong copyleft” because the condition to distributed under the same
|
||
license has the largest possible scope and extends to all derivative
|
||
works.
|
||
|
||
#### Patents
|
||
|
||
Certain software, and in particular software that implements
|
||
multimedia standard formats such as MP3, MPEG 2 video and audio, h.264,
|
||
MPEG 4 audio and video, AC3, etc, can have patent issues. In certain
|
||
countries patents are granted on software and even software-only
|
||
solution are by and large considered patentable and are patented (such
|
||
as in the United States). In certain others, patents on pure software
|
||
solutions are formally prohibited, but granted (this is the case in many
|
||
European countries), and in others again are neither allowed nor granted.
|
||
|
||
It is up to you to make sure that in the countries where GStreamer is
|
||
used, products are made using it and product are distributed, a license
|
||
from the applicable patent holders is required or not. Receiving GStreamer
|
||
– or links to other downloadable software – does not provide any license
|
||
expressed or implied over these patents, except in very limited
|
||
conditions where the license so provides. No representation is made.
|
||
|
||
In certain cases, the optional packages are distributed only as source
|
||
code. It is up to the receiver to make sure that in the applicable
|
||
circumstances compiling the same code for a given platform or
|
||
distributing the object code is not an act that infringes one or more
|
||
patents.
|
||
|
||
## Software is as-is
|
||
|
||
All software and the entire GStreamer binaries are provided as-is, without any
|
||
warranty whatsoever. The individual licenses have particular language
|
||
disclaiming liability: we invite you to read all of them. Should you
|
||
need a warranty on the fact that software works as intended or have any
|
||
kind of indemnification, you have the option to subscribe a software
|
||
maintenance agreement with a company or entity that is in that business.
|
||
|
||
|
||
## Licensing of code contributed to GStreamer itself
|
||
|
||
GStreamer is a plugin-based framework licensed under the LGPL. The
|
||
reason for this choice in licensing is to ensure that everyone can use
|
||
GStreamer to build applications using licenses of their choice.
|
||
|
||
To keep this policy viable, the GStreamer community has made a few licensing
|
||
rules for code to be included in GStreamer's core or GStreamer's
|
||
official modules, like our plugin packages.
|
||
|
||
**We require that all code going into our core packages is LGPL.**
|
||
|
||
For the plugin code, we require the <B>use of the LGPL for all plugins
|
||
written from scratch or linking to external libraries</B>. The only
|
||
exception to this is when plugins contain older code under the BSD and
|
||
MIT license. They can use those licenses instead and will still be
|
||
considered for inclusion, we do prefer that all new code written
|
||
though is at least dual licensed LGPL. We do not accept GPL code to be
|
||
added to our plugins modules, but we do accept LGPL-licensed plugins
|
||
using an external GPL library for some of our plugin modules. The
|
||
reason we demand plugins be licensed under the LGPL, even when they
|
||
are using a GPL library, is that other developers might want to use
|
||
the plugin code as a template for plugins linking to non-GPL
|
||
libraries. We also accept dual licensed plugins for inclusion as long
|
||
as one of the licenses offered for dual licensing is the LGPL.
|
||
|
||
We also do not allow plugins under any license into our core,base
|
||
or good packages if they have known patent issues associated with
|
||
them. This means that even a contributed LGPL/MIT licensed
|
||
implementation of something which there is a licensing body claiming
|
||
fees for, those plugins would need to go into our gst-plugins-ugly
|
||
module.
|
||
|
||
All new plugins, regardless of licensing or patents
|
||
tend to have to go through a period in our incubation module,
|
||
gst-plugins-bad before moving to ugly, base or good.
|
||
|
||
## Frequently Asked Questions
|
||
|
||
#### What licenses are there?
|
||
|
||
GStreamer binaries contain software under various licenses. See above.
|
||
|
||
#### How does this relate to the packaging system?
|
||
|
||
The packaging is only a more convenient way to install software and
|
||
decide what's good for you. GStreamer is meant to be modular, making use
|
||
of different modules, or plugins, that perform different activities.
|
||
|
||
We provide some of them by default. Others are provided as an additional
|
||
download, should you elect to do so. You could do the same by finding
|
||
and downloading the same packages for your own platform. So it is
|
||
entirely up to you to decide what to do.
|
||
|
||
Also, we note that GStreamer elements are divided into different packages,
|
||
roughly following the licensing conditions attached to the same. For
|
||
instance, the codecs-gpl package contains GPL licensed codecs. All the
|
||
packages installed by default, conversely, are licensed under the LGPL
|
||
or a more liberal license. This division is provided only for ease of
|
||
reference, but we cannot guarantee that our selection is 100% correct,
|
||
so it is up to the user to verify the actual licensing conditions before
|
||
distributing works that utilize GStreamer.
|
||
|
||
#### Can I / must I distribute GStreamer along with my application?
|
||
|
||
You surely can. All software is Free/Open Source software, and can be
|
||
distributed freely. You are not **required** to distribute it. Only,
|
||
be reminded that one of the conditions for you to use software under
|
||
certain licenses to make a work containing such software, is that you
|
||
also distribute the complete source code of the original code (or of
|
||
the modified code, if you have modified it). There are alternative
|
||
ways to comply with this obligation, some of them do not require any
|
||
actual distribution of source code, but since GStreamer contains the
|
||
entire source code, you might want to include it (or the directories
|
||
containing the source code) with your application as a safe way to
|
||
comply with this requirement of the license.
|
||
|
||
#### What happens when I modify the GStreamer's source code?
|
||
|
||
You are invited to do so, as the licenses (unless you are dealing with
|
||
proprietary bits, but in that case you will not find the corresponding
|
||
source code) so permit. Be reminded though that in that case you need
|
||
to also provide the complete corresponding source code (and to
|
||
preserve the same license, of course). You might also consider to push
|
||
your modifications upstream, so that they are merged into the main
|
||
branch of development if they are worth it and will be maintained by
|
||
the GStreamer project and not by you individually. We invite you not
|
||
to fork the code, if at all possible. The Cerbero build system has a
|
||
"bundle-source" command that can help you create a source bundle
|
||
containing all of the complete corresponding machine readable source
|
||
code that you are required to provide.
|
||
|
||
#### How does licensing relate to software patents? What about software patents in general?
|
||
|
||
This is a tricky question. We believe software patents should not exist,
|
||
so that by distributing and using software on a general purpose machine
|
||
you would not violate any of them. But the inconvenient truth is that
|
||
they do exist.
|
||
|
||
Software patents are widely available in the USA. Even though they are
|
||
formally prohibited in the European Union, they indeed are granted by
|
||
the thousand by the European Patent Office, and also some national
|
||
patent offices follow the same path. In other countries they are not
|
||
available.
|
||
|
||
Since patent protection is a national state-granted monopoly,
|
||
distributing software that violates patents in a given country could be
|
||
entirely safe if done in another country. Fair use exceptions also
|
||
exist. So we cannot advise you whether the software we provide would be
|
||
considered violating patents in your country or in any other country,
|
||
but that can be said for virtually all kinds of software. Only, since we
|
||
deal with audio-video standards, and these standards are by and large
|
||
designed to use certain patented technologies, it is common wisdom that
|
||
the pieces of software that implement these standards are sensitive in
|
||
this respect.
|
||
|
||
This is why GStreamer has taken a modular approach, so that you can use
|
||
a Free plugins or a proprietary, patent royalty bearing, plugin for a
|
||
given standard.
|
||
|
||
#### What about static vs. dynamic linking and copyleft?
|
||
|
||
We cannot provide one single answer to that question. Since copyright in
|
||
software works as copyright in literature, static linking means
|
||
basically that the programmer includes bits of code of the original
|
||
library in the bytecode at compile time. This amounts to make derivative
|
||
code of the library without conceivable exceptions, so you need a
|
||
permission from the copyright holders of the library to do this.
|
||
|
||
A widespread line of thinking says that dynamic linking is conversely
|
||
not relevant to the copyleft effect, since the mingling of code in a
|
||
larger work is done at runtime. However, another equally authoritative
|
||
line of thought says that only certain type of dynamic linking is not
|
||
copyright relevant. Therefore, using a library that is specifically
|
||
designed to be loaded into a particular kind of software, even through
|
||
API, requires permission by the copyright holder of the library when
|
||
the two pieces are distributed together.
|
||
|
||
In all cases, since most of the software we include in GStreamer is under
|
||
the LGPL, this permission is granted once for all, subject to compliance
|
||
with the conditions set out by it. Therefore, the problem only arises
|
||
when you want to use GPL libraries to make non-GPL applications, and you
|
||
need to audit your software in that case to make sure that what you do
|
||
is not an infringement. This is why we have put the GPL libraries in a
|
||
separate set of optional components, so you have a clearer view of what
|
||
is safely clear for use, and what might need better investigation on a
|
||
case-by-case basis.
|
||
|
||
Please be reminded that even for LGPL, the recipient of the software
|
||
must be in a position to replace the current library with a modified
|
||
one, and to that effect some conditions apply, among which that for
|
||
static linking you must also provide the complete toolchain required to
|
||
relink the library (“any data and utility programs needed for
|
||
reproducing the executable from it”, except the “major components”) and
|
||
that the license of the conditions of the resulting program must allow
|
||
decompilation to debug modifications to the library.
|
||
|
||
## Licensing applications under the GNU GPL using GStreamer
|
||
|
||
The licensing of GStreamer is no different from a lot of other libraries out
|
||
there like GTK+ or glibc:
|
||
we use the [LGPL](http://www.fsf.org/licenses/lgpl.html).
|
||
|
||
What complicates things with regards to GStreamer is its plugin-based design
|
||
and the heavily patented and proprietary nature of many multimedia codecs.
|
||
While patents on software are currently only allowed in a small minority of
|
||
world countries (the US and Australia being the most important of those), the
|
||
problem is that due to the central place the US hold in the world economy and
|
||
the computing industry, software patents are hard to ignore wherever you are.
|
||
|
||
Due to this situation, many companies, including major GNU/Linux distributions,
|
||
get trapped in a situation where they either get bad reviews due to lacking
|
||
out-of-the-box media playback capabilities (and attempts to educate the
|
||
reviewers have met with little success so far), or go against their
|
||
own - and the free software movement's - wish to avoid proprietary software.
|
||
|
||
Due to competitive pressure, most choose to add some support. Doing that
|
||
through pure free software solutions would have them risk heavy litigation and
|
||
punishment from patent owners. So when the decision is made to include support
|
||
for patented codecs, it leaves them the choice of either using special
|
||
proprietary applications, or try to integrate the support for these codecs
|
||
through proprietary plugins into the multimedia infrastructure provided by
|
||
GStreamer. Faced with one of these two evils the GStreamer community of
|
||
course prefer the second option.
|
||
|
||
The problem which arises is that most free software and open source
|
||
applications developed use the GPL as their license. While this is generally a
|
||
good thing, it creates a dilemma for people who want to put together a
|
||
distribution. The dilemma they face is that if they include proprietary
|
||
plugins in GStreamer to support patented formats in a way that is legal for
|
||
them, they do risk running afoul of the GPL license of the applications. We
|
||
have gotten some conflicting reports from lawyers on whether this is actually a
|
||
problem, but the official stance of the FSF is that it is a problem.
|
||
We view the FSF as an authority on this matter, so we are inclined to follow
|
||
their interpretation of the GPL license.
|
||
|
||
So what does this mean for you as an application developer? Well, it
|
||
means **you have to make an active decision on whether you want your
|
||
application to be used together with proprietary plugins or
|
||
not**. What you decide here will also influence the chances of
|
||
commercial distributions and Unix vendors shipping your
|
||
application. The GStreamer community suggest you license your software
|
||
using a license that will allow non-free, patent implementing or
|
||
non-GPL compatible plugins to be bundled with GStreamer and your
|
||
applications, in order to make sure that as many vendors as possible
|
||
go with GStreamer instead of less free solutions. This in turn we
|
||
hope and think will let GStreamer be a vehicle for wider use of free
|
||
formats like the [Xiph.org](http://www.xiph.org/) formats.
|
||
|
||
If you do decide that you want to allow for non-free plugins to be used with
|
||
your application you have a variety of choices. One of the simplest is using
|
||
licenses like LGPL, MPL or BSD for your application instead of the GPL.
|
||
Or you can add a exceptions clause to your GPL license stating that you except
|
||
GStreamer plugins from the obligations of the GPL.
|
||
|
||
A good example of such a GPL exception clause would be, using the Totem
|
||
video player project as an example:
|
||
|
||
*The developers of the Totem video player hereby grants permission for
|
||
non-GPL compatible GStreamer plugins to be used and distributed together
|
||
with GStreamer and Totem. This permission is above and beyond the permissions
|
||
granted by the GPL license by which Totem is covered. If you modify this code,
|
||
you may extend this exception to your version of the code, but you are
|
||
not obligated to do so. If you do not wish to do so, delete this exception
|
||
statement from your version.*
|
||
|
||
Our suggestion among these choices is to use the LGPL license, as it is what
|
||
resembles the GPL most and it makes it a good licensing fit with the major
|
||
GNU/Linux desktop projects like GNOME and KDE. It also allows you to share
|
||
code more openly with projects that have compatible licenses. As you might
|
||
deduce, pure GPL licensed code without the above-mentioned clause is not
|
||
re-usable in your application under a GPL plus exception clause unless you
|
||
get the author of the pure GPL code to allow a relicensing to GPL plus
|
||
exception clause. By choosing the LGPL, there is no need for an exception
|
||
clause and thus code can be shared freely between your application and
|
||
other LGPL using projects.
|
||
|
||
We have above outlined the practical reasons for why the GStreamer community
|
||
suggest you allow non-free plugins to be used with your applications. We feel
|
||
that in the multimedia arena, the free software community is still not strong
|
||
enough to set the agenda and that blocking non-free plugins to be used in our
|
||
infrastructure hurts us more than it hurts the patent owners and their ilk.
|
||
|
||
This view is not shared by everyone.
|
||
The [Free Software Foundation](http://www.fsf.org) urges you to use
|
||
an unmodified GPL for your applications, so as to push back against the
|
||
temptation to use non-free plug-ins. They say that since not everyone else has
|
||
the strength to reject them because they are unethical, they ask your help to
|
||
give them a legal reason to do so.
|