GStreamer

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GStreamer
Developer(s) GStreamer Team
Initial release 11 January 2001 (2001-01-11)[1]
Stable release 1.2.1 / 10 November 2013 (2013-11-10)[2]
Development status Active
Written in C[3]
Operating system Cross-platform
Type Multimedia framework
License GNU LGPL
Website gstreamer.freedesktop.org

GStreamer is a pipeline-based multimedia framework written in the C programming language with the type system based on GObject.

GStreamer allows a programmer to create a variety of media-handling components, including simple audio playback, audio and video playback, recording, streaming and editing. The pipeline design serves as a base to create many types of multimedia applications such as video editors, streaming media broadcasters and media players.

Designed to be cross-platform, it is known to work on Linux (x86, PowerPC and ARM), Solaris (Intel and SPARC) and OpenSolaris, FreeBSD, OpenBSD, NetBSD, Mac OS X, Microsoft Windows, and OS/400. GStreamer has bindings for programming-languages like Python, Vala, C++, Perl, GNU Guile and Ruby. GStreamer is licensed under the GNU Lesser General Public License.[4]

Distribution and adoption

The GNOME desktop environment, a heavy user of GStreamer technology, has included GStreamer since GNOME version 2.2 and encourages GNOME and GTK+ applications to use it. Other projects also use or support it, such as the Chameleo media platform, the Phonon media framework and the Songbird media player.

GStreamer also operates in embedded devices like the Palm Pre,[5] Tizen and the Nokia 770, N800, N810, N900 and N9 Internet Tablets running the Maemo operating system.

GStreamer is also distributed by Collabora and Fluendo as a free and open source multiplatform SDK, available on gstreamer.com (rather than gstreamer.freedesktop.org for the upstream community project). Developers working with the SDK will find it to be functionally identical on Windows, Mac OS X, iOS, Android and all supported Linux platforms. The SDK initiative aims to facilitate the commercial adoption of the GStreamer project, as it provides a standardized entry point to developing multimedia applications with GStreamer, without needing to build the entire platform by oneself. Users of the SDK also benefit from additional documentation, tutorials and instructions for installing and getting started with GStreamer.

While the GStreamer SDK currently only ships a version of GStreamer based on the 0.10 series, the GStreamer community has provided[6] binary builds of GStreamer 1.0.7 using the same build tools as the SDK.

Technical overview

GStreamer processes media by connecting a number of processing elements into a pipeline. Each element is provided by a plug-in. Elements can be grouped into bins, which can be further aggregated, thus forming a hierarchical graph. This is an example of a filter graph.

Elements communicate by means of pads. A source pad on one element can be connected to a sink pad on another. When the pipeline is in the playing state, data buffers flow from the source pad to the sink pad. Pads negotiate the kind of data that will be sent using capabilities.

The diagram to the right could exemplify playing an MP3 file using GStreamer. The file source reads an MP3 file from a computer's hard-drive and sends it to the MP3 decoder. The decoder decodes the file data and converts it into PCM samples which then pass to the ALSA sound-driver. The ALSA sound-driver sends the PCM sound samples to the computer's speakers.

Plug-ins

GStreamer uses a plug-in architecture which makes the most of GStreamer's functionality implemented as shared libraries.[7] GStreamer's base functionality contains functions for registering and loading plug-ins and for providing the fundamentals of all classes in the form of base classes. Plug-in libraries get dynamically loaded to support a wide spectrum of codecs, container formats, input/output drivers and effects.

Plug-ins can be installed semi-automatically when they are first needed. For that purpose distributions can register a backend that resolves feature-descriptions to package-names.

Since version 0.10, the plug-ins come grouped into three sets (named after the film The Good, the Bad and the Ugly),

Plug-in set name Description
Good This package contains the GStreamer plug-ins from the "good" set, a set of high quality plug-ins under the LGPL license,[8] or according to Gstreamer, "contains a set of well-supported plug-ins under our preferred license".[9]
Bad GStreamer Bad Plug-ins comprises a set of plug-ins not up-to-par compared to the rest. They might closely approach good-quality plug-ins, but they lack something: perhaps a good code review, some documentation, a set of tests, a real live maintainer, or some actual wide use.[10]
Ugly This package contains plug-ins from the "ugly" set, a set of good-quality plug-ins that might pose distribution problems.[11]

Individual distributions may further sub-classify these plug-ins: for example Ubuntu groups the "bad" and "ugly" sets into the "Universe" or the "Multiverse" components.

There's also a separate GStreamer FFmpeg plug-in, which is a FFmpeg-based plug-in that supports many additional media formats. It was first released on 26 February 2004, with version number 0.7.1. [12] [13]

This plugin can transparently use Libav, and as such is often called the GStreamer Libav plug-in in recent Linux distributions.

Media formats

The Good, Bad and Ugly GStreamer plugins mentioned earlier provide, alongside processing elements/filters of all kinds, support for a wide variety of file formats, protocols and multimedia codecs.

In addition to those, support for more than a hundred codecs (including MPEG-1, MPEG-2, MPEG-4, H.261, H.263, H.264, RealVideo, MP3, WMV, FLV, etc.[14][15]) is transparently provided through the GStreamer FFmpeg/libav plug-in. See the Libav and FFmpeg pages for a complete list of media formats provided by these plug-ins.

History and development

Early days

Erik Walthinsen founded the GStreamer project in 1999. Many of its core design ideas came from a research project at the Oregon Graduate Institute. Wim Taymans joined the project soon thereafter and greatly expanded on many aspects of the system. Many others around the world have contributed to various degrees since then.

The first major release was 0.1.0 which was announced on 11 January 2001.[1] Not long after, GStreamer picked up its first commercial backer, an embedded Linux company called RidgeRun. Towards the end of January 2001, they hired Erik Walthinsen to develop methods for embedding GStreamer in smaller (cell phone-class) devices. Another RidgeRun employee, Brock A. Frazier, designed the GStreamer logo. RidgeRun later ran into financial trouble and had to let its staff go, including Erik Walthinsen. GStreamer progress was mostly unaffected.

The project released a series of major releases with 0.2.0 coming out in July 2001, 0.4.0 in September 2002, and 0.8.0 in March 2004. During that period the project also changed its versioning strategy and while the first releases were simply new versions, later on the middle number started signifying release series. This meant the project did release a string of 0.6.x and 0.8.x releases which was meant to stay binary compatible within those release series. Erik Walthinsen more or less left GStreamer development behind during this time as he went on to focus on other ventures.

During the 0.8.x release series, the project faced some difficulties. The 0.8.x series was not very popular in the Linux community mostly because of stability issues and a serious lack of features compared to competing projects like Xine, MPlayer or VLC. The project also suffered a bit in terms of lack of leadership as Wim Taymans, who had been the project lead since Erik Walthinsen had left, had also mostly ceased active participation.

The 0.10 series

In 2004, a new company was founded, Fluendo, which wanted to use GStreamer to write a streaming server Flumotion and also provide multimedia solutions for GStreamer. During this time, Fluendo hired most of the core developers including Wim Taymans and attracted the support of companies such as Nokia and Intel to bring GStreamer to a professional level and drive community adoption.

With Wim Taymans back at the helm, the core of GStreamer was redesigned and became what is the current 0.10.x series, which had its first release (0.10.0) in December 2005.[16] It has maintained API and ABI compatibility since.

With a new stable core in place, GStreamer gained in popularity in 2006, being used by media players including Totem, Rhythmbox and Banshee with many more to follow.

GStreamer has also continued seeing both open source and commercial success and adoption by many different corporations (Nokia, Motorola, Texas Instruments, Freescale, Tandberg, Intel and many more) and has become a very powerful cross platform multimedia framework.

In 2007, most of the core GStreamer developers left Fluendo, including GStreamer maintainer Wim Taymans who went on to co-found Collabora Multimedia together with other GStreamer veterans, while others joined Sun Microsystems, Oblong and Songbird.

The 1.x series

GStreamer 1.0 was released on September 24, 2012.[17] The 1.x series is parallel installable to GStreamer 0.10 to ease the transition, and provides many architectural advantages over the 0.10 series.[18] Generally speaking, GStreamer 1.0 brought significant improvements for:

  • Embedded processors support, lower power consumption, offloading work to specialized hardware units (such as DSPs)
  • Hardware accelerated video decoding/encoding using GPUs
  • Zero-copy memory management (avoiding unnecessary roundtrips between the CPU and GPU) for better performance and lower power consumption
  • Dynamic pipelines
  • API and code cleanups

Beyond the technical improvements, the 1.x series is also defined by a new release versioning scheme. As the GStreamer roadmap explains,[19] all 1.x.y versions carry a -1.0 API version suffix and have a stable API/ABI. The API/ABI can only be broken by a new major release series (ie: 2.x); however, there are currently no plans for a 2.0 release series. Until then, the new version numbering scheme can be used to predict the intended use of each release. The roadmap cites some examples:

  • 1.0.0, 1.0.1, 1.0.2, 1.0.3... stable release and follow-up bug-fix releases
  • 1.1.0, 1.1.1, 1.1.2, 1.1.3... pre-releases, development version leading up to 1.2.0
  • 1.2.0, 1.2.1, 1.2.2, 1.2.3... stable release and follow-up bug-fix releases
  • 1.3.0, ..
  • 1.4.0, ..
  • etc.

In March 2013, the GStreamer project maintainers issued a statement[20] to clarify that the 0.10 series is no longer maintained. The statement reasserted the GStreamer project's willingness to help application and plugin developers migrate to the new technology, and hinted that those for whom switching to the 1.x series was still considered impossible could seek assistance from various consulting companies.

The "GStreamer SDK" is, for the time being, still using GStreamer 0.10.[21] While no plans have been outlined by Collabora and Fluendo to provide official support for the 1.x series in the SDK at this time, the GStreamer community has provided[6] binary builds of GStreamer 1.0.7 using the same build tools as the GStreamer SDK.

1.2 added support for DASH adaptive streaming, JPEG2000 images, VP9 and Daala video, and decoding-only support for WebP.

See also

References

  1. ↑ 1.0 1.1 "GStreamer "Slipstream" 0.1.0 released". 11 January 2001. Retrieved 3 November 2010. 
  2. ↑ Release notes for GStreamer 1.2.1, 10 November 2013, retrieved 22 November 2013 
  3. ↑ "GStreamer", Ohloh Analysis Summary, Ohloh, retrieved 8 February 2012 
  4. ↑ "Licensing your applications and plugins for use with GStreamer". gstreamer.freedesktop.org. Retrieved 22 July 2010. 
  5. ↑ "webOS and GStreamer". webOShelp. Retrieved 25 July 2009. 
  6. ↑ 6.0 6.1 http://lists.freedesktop.org/archives/gstreamer-devel/2013-June/041449.html
  7. ↑ Overview of the modules, gstreamer.freedesktop.org, retrieved 8 February 2012 
  8. ↑ gstreamer0.10-plugins-good package description (Ubuntu 10.04)
  9. ↑ "Release notes for GStreamer Base Plug-ins 0.10.0". Retrieved 3 November 2010. 
  10. ↑ gstreamer0.10-plugins-bad package description (Ubuntu 10.04)
  11. ↑ gstreamer0.10-plugins-ugly package description (Ubuntu 10.04)
  12. ↑ News, Gstreamer.freedesktop.org, retrieved 7 February 2012 
  13. ↑ Release notes for GStreamer FFmpeg plugin 0.7.1 "True Colors", Gstreamer.freedesktop.org, retrieved 7 February 2012 
  14. ↑ FFmpeg plug-in, Gstreamer.freedesktop.org, retrieved 7 February 2012 
  15. ↑ ext/ffmpeg/gstffmpegcodecmap.c, Cgit.freedesktop.org, retrieved 7 February 2012 
  16. ↑ "GStreamer 0.10.0 stable release - Announcement of the first release in 0.10 stable series". Retrieved 3 November 2010. 
  17. ↑ "GStreamer 1.0 released (gstreamer.freedesktop.org)". 
  18. ↑ https://lwn.net/Articles/464270/
  19. ↑ http://gstreamer.freedesktop.org/wiki/ReleasePlanning2013
  20. ↑ http://lists.freedesktop.org/archives/gstreamer-announce/2013-March/000273.html
  21. ↑ "2013.6 Congo - GStreamer SDK documentation". gstreamer.com. Retrieved 16 September 2013. 

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