GStreamer

GStreamer

Developer(s)	GStreamer Team
Initial release	11 January 2001 (2001-01-11)
Stable release	1.0.7 / 26 April 2013 (2013-04-26)
Development status	Active
Written in	C
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.

Distribution

The GNOME desktop environment, the primary 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, Tizen and the Nokia 770, N800, N810, N900 and N9 Internet Tablets running the Maemo operating system.

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. 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. 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 and the GStreamer SDK

On June the 7th 2012, the first GStreamer SDK was launched using a stable version of GStreamer to favor cross-platform application development with this framework. Developers working with the SDK will find it to be functionally identical on Windows XP, Windows Vista, Windows 7, Mac OS X (version 10.5 or later on Intel) and all supported Linux platforms. This initiative aims to facilitate the commercial adoption of the GStreamer project. As well as the SDK itself, users gain access to extensive documentation, tutorials and clear instructions for installing and getting started with GStreamer.

GStreamer 1.0 was released on September 24, 2012. The 1.x series is parallel installable to GStreamer 0.10 to ease the transition.

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 above-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 FFmpeg plug-in

Developer(s)	GStreamer Team
Initial release	26 February 2004 (2004-02-26)
Stable release	0.10.13 / 2 November 2011 (2011-11-02)
Development status	Active
Written in	C
Operating system	Cross-platform
Platform	GStreamer
Type	Multimedia framework plug-in
License	GNU GPL
Website	gstreamer.freedesktop.org/modules/gst-ffmpeg.html

GStreamer uses a plug-in architecture which makes the most of GStreamer's functionality implemented as shared libraries. 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, or according to Gstreamer, "contains a set of well-supported plug-ins under our preferred license".
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.
Ugly	This package contains plug-ins from the "ugly" set, a set of good-quality plug-ins that might pose distribution problems.

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 media formats such as MPEG-1, MPEG-2, MPEG-4, H.261, H.263, H.264, RealVideo, MP3, WMV, FLV, etc. It was first released on 26 February 2004, with version number 0.7.1.

See also

• OggConvert, a simple GUI front end
• Helix DNA
• MPlayer
• VLC
• XBMC Media Center
• Xine
• PiTiVi

External links

• Official website
• An introduction to GStreamer
• GStreamer project on Ohloh
• #gstreamer on freenode
• GStreamer FFmpeg plug-in website
• Windows binary installer packages
• Mac OS X binary installer packages