GPAC Project on Advanced Content

Last updated
GPAC
Developer(s) Jean Le Feuvre, People@GPAC [1] [2]
Initial release2003;20 years ago (2003) [3]
Stable release
2.2.1 [4]   OOjs UI icon edit-ltr-progressive.svg / 27 April 2023;7 months ago (27 April 2023)
Repository
Written in C
Operating system Cross-platform
Available inEnglish
Type Multimedia framework
License LGPL v2.1
Website gpac.io

GPAC Project on Advanced Content (GPAC, a recursive acronym) is an implementation of the MPEG-4 Systems standard written in ANSI C. GPAC provides tools for media playback, vector graphics and 3D rendering, MPEG-4 authoring and distribution. [5]

Contents

GPAC provides three sets of tools based on a core library called libgpac:

GPAC is cross-platform. It is written in (almost 100% ANSI) C for portability reasons, attempting to keep the memory footprint as low as possible. It is currently running under Windows, Linux, Solaris, Windows CE (SmartPhone, PocketPC 2002/2003), iOS, Android, Embedded Linux (familiar 8, GPE) and recent Symbian OS systems.

The project is intended for a wide audience ranging from end-users or content creators with development skills who want to experiment the new standards for interactive technologies or want to convert files for mobile devices, to developers who need players and/or server for multimedia streaming applications.

The GPAC framework is being developed at École nationale supérieure des télécommunications (ENST) as part of research work on digital media.

History and standards

GPAC was founded in New York City in 1999. [6] In 2003, it became an open-source project, with the initial goal of developing from scratch, in ANSI C, clean software compliant with the MPEG-4 Systems standard, as a small and flexible alternative to the MPEG-4 reference software. [3]

In parallel, the project has evolved and now supports many other multimedia standards, with support for X3D, W3C SVG Tiny 1.2, and OMA/3GPP/ISMA and MPEG Dynamic Adaptive Streaming over HTTP (MPEG-DASH) features. 3D support is available on embedded platforms through OpenGL-ES.[ citation needed ] The MPEG-DASH feature can be used to reconstruct .mp4 files from videos streamed and cached in this format (e.g., YouTube). [7] Various research projects used or use GPAC. [8]

Since 2013, GPAC Licensing has offered business support and closed-source licenses. [9]

Multimedia content features

Packaging

GPAC features encoders and multiplexers, publishing and content distribution tools for MP4 files and many tools for scene descriptions (BIFS/VRML/X3D converters, SWF/BIFS, SVG/BIFS, etc....). MP4Box provides all these tools in a single command-line application, albeit with extremely arcane syntax. Current supported features are: [10]

Playing

GPAC supports many protocols and standards, among which: [10]

Streaming

As of version 0.4.5, GPAC has some experimental server-side and streaming tools: [10]

Contributors

The project is hosted at ENST, a leading French engineering school also known as Télécom Paris. Current main contributors of GPAC are: [2]

Other (current or past) contributors from ENST are: [2]

Additionally, GPAC is used at ENST for pedagogical purposes. Students regularly participate in the development of the project. [2]

Related Research Articles

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SVG is an XML-based vector image format for defining two-dimensional graphics, having support for interactivity and animation. The SVG specification is an open standard developed by the World Wide Web Consortium since 1999.

<span class="mw-page-title-main">Synchronized Multimedia Integration Language</span> XML-based markup language for multimedia presentations

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X3D is a set of royalty-free ISO/IEC standards for declaratively representing 3D computer graphics. X3D includes multiple graphics file formats, programming-language API definitions, and run-time specifications for both delivery and integration of interactive network-capable 3D data. X3D version 4.0 has been approved by Web3D Consortium, and is under final review by ISO/IEC as a revised International Standard (IS).

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MPEG-4 Part 17, or MPEG-4 Timed Text (MP4TT), or MPEG-4 Streaming text format is the text-based subtitle format for MPEG-4, published as ISO/IEC 14496-17 in 2006. It was developed in response to the need for a generic method for coding of text as one of the multimedia components within audiovisual presentations.

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Dynamic Adaptive Streaming over HTTP (DASH), also known as MPEG-DASH, is an adaptive bitrate streaming technique that enables high quality streaming of media content over the Internet delivered from conventional HTTP web servers. Similar to Apple's HTTP Live Streaming (HLS) solution, MPEG-DASH works by breaking the content into a sequence of small segments, which are served over HTTP. An early HTTP web server based streaming system called SProxy was developed and deployed in the Hewlett Packard Laboratories in 2006. It showed how to use HTTP range requests to break the content into small segments. SProxy shows the effectiveness of segment based streaming, gaining best Internet penetration due to the wide deployment of firewalls, and reducing the unnecessary traffic transmission if a user chooses to terminate the streaming session earlier before reaching the end. Each segment contains a short interval of playback time of content that is potentially many hours in duration, such as a movie or the live broadcast of a sport event. The content is made available at a variety of different bit rates, i.e., alternative segments encoded at different bit rates covering aligned short intervals of playback time. While the content is being played back by an MPEG-DASH client, the client uses a bit rate adaptation (ABR) algorithm to automatically select the segment with the highest bit rate possible that can be downloaded in time for playback without causing stalls or re-buffering events in the playback. The current MPEG-DASH reference client dash.js offers both buffer-based (BOLA) and hybrid (DYNAMIC) bit rate adaptation algorithms. Thus, an MPEG-DASH client can seamlessly adapt to changing network conditions and provide high quality playback with few stalls or re-buffering events.

References

  1. 1 2 3 4 Jean Le Feuvre; Cyril Concolato; Jean-Claude Moissinac (2007). "GPAC: open source multimedia framework". Proceedings of the 15th International Conference on Multimedia. ACM Digital Library. pp. 1009–1012. doi:10.1145/1291233.1291452. ISBN   978-1-59593-702-5.
  2. 1 2 3 4 "About us". People@GPAC. Retrieved 2014-01-28.
  3. 1 2 3 Romain Bouqueau (2014-01-22). "5000th commit, 10 years of open-source software". People@GPAC. Retrieved 2014-01-28.
  4. ↑ "Release 2.2.1". 27 April 2023. Retrieved 1 May 2023.
  5. 1 2 3 Jean Le Feuvre; Cyril Concolato (December 2012). "GPAC, Toolbox for Interactive Multimedia Packaging, Delivery and Playback". Open Source Column. ACM SIGMM Records. ISSN   1947-4598. Archived from the original on 2014-01-29. Retrieved 2014-01-28.
  6. ↑ GPAC (2013). "About us". GPAC Licensing. Retrieved 2014-01-28.
  7. ↑ Sofer, Nir (2013). "VideoCacheView". NirSoft.net. Retrieved 2014-01-28. uses MP4Box installed as a part of GPAC package to convert the MPEG-DASH streams into a valid mp4
  8. ↑ GPAC. "Other academic works using GPAC". Publications. People@GPAC. Retrieved 2014-01-28.
  9. 1 2 Bouqueau, Romain (2013-05-09). "GPAC Licensing". GPAC Licensing. Retrieved 2014-01-28. The GPAC and MP4Box trademarks are internationally registered by Telecom ParisTech
  10. 1 2 3 "GPAC features". People@GPAC. Retrieved 2014-01-28.
  11. 1 2 3 4 5 6 Cyril Concolato; Jean Le Feuvre; Jean-Claude Moissinac (May 2008). "Design of an Efficient Scalable Vector Graphics Player for Constrained Devices". IEEE Transactions on Consumer Electronics. IEEE Transactions on Consumer Electronics (Vol. 54 issue 2). 54 (2): 895–903. CiteSeerX   10.1.1.648.6798 . doi:10.1109/TCE.2008.4560176. S2CID   1722027 . Retrieved 2014-01-28.
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