World Library  
My Account |  Register |  Help  
  
Flag as Inappropriate
Email this Article
 

Libav

Libav
Screenshot of the movie Sintel being played using the avplay program from the Libav project.
Developer(s) Libav team
Initial release March 13, 2011 (2011-03-13)[1]
Stable release 11 (September 13, 2014 (2014-09-13))
Development status Active
Written in C[2]
Operating system Cross-platform
Platform Multi-platform
Type Multimedia framework
License GNU LGPL 2.1+
GNU GPL 2+
Website .orglibav

Libav is a free software project that produces libraries and programs for handling multimedia data. The most notable parts of Libav are libavcodec, an audio/video codec library used by several other projects, libavformat, an audio/video container mux and demux library, and the avconv command line program for transcoding multimedia files. The Libav source code is published under the GNU Lesser General Public License 2.1+.[3]

Libav is developed for many operating systems, including GNU/Linux, Mac OS X, Microsoft Windows, AmigaOS and its heir MorphOS. Most computing platforms and microprocessor instruction set architectures are also supported, like x86 (IA-32 and x86-64), PPC (PowerPC), ARM, DEC Alpha, SPARC, and MIPS architecture.[4]

The Libav logo uses a zigzag pattern that shows how MPEG video codecs handle entropy encoding.[5] It was previously the logo of the FFmpeg project until LibAV was forked from it. Following the fork, in 2011 one of the LibAV developers Måns Rullgård claimed copyright over the logo and requested FFmpeg cease and desist from using it.[6] FFmpeg subsequently altered their logo.[7]

Contents

  • History 1
    • Fork from FFmpeg 1.1
    • Software using Libav instead of FFmpeg 1.2
  • Legal aspects 2
  • Google Summer of Code participation 3
  • List of project's components 4
  • Contained codecs 5
    • Video codecs 5.1
    • Audio codecs 5.2
    • Supported file formats 5.3
    • Supported protocols 5.4
  • See also 6
  • References 7
  • External links 8

History

Fork from FFmpeg

The Libav project is a fork of the FFmpeg project[8] which was originally started by Fabrice Bellard[3] (using the pseudonym "Gerard Lantau"). The Libav project was announced on March 13, 2011 by a group of FFmpeg developers.[9][10][11] The event seems related to an issue in project management.[12][13]

Software using Libav instead of FFmpeg

Since the time of the fork, the maintainer of FFmpeg packages for Debian[14] and Ubuntu,[15] being one of the group of developers who forked FFmpeg, have switched to this fork. Hence most software on these systems that earlier used FFmpeg now automatically use Libav.

With Gentoo, users are free to choose between FFmpeg and its fork libav by the way they install their "virtual" FFmpeg.[16] Arch Linux has a source port in AUR, which is its additional repository for packages provided by the community but not being maintained by the arch developers themselves.[17] MPlayer2, a fork of MPlayer, uses Libav exclusively. GStreamer supports both through different plugins.

Legal aspects

Libav contains more than 100 codecs.[18] Many codecs that compress information have been claimed by patent holders.[19] Such claims may be enforceable in countries like the United States which have implemented software patents, but are considered unenforceable or void in countries that have not implemented software patents.

Google Summer of Code participation

As of 2012, Libav has been successful in being accepted into the Google Summer of Code program in both years since its inception.[20]

With participation in the Google Summer of Code, Libav has had many new features and improvements done for various components of Libav. These new features and improvements include implementing a WMVP/WVP2 decoder, hardware accelerated H.264 decoding on Android, and G.723.1 codec support.[20]

List of project's components

avconv
A video and audio converter that can also grab from a live audio/video source.
avserver
A streaming server for both audio and video.
avplay
A very simple and portable media player using the Libav libraries and the SDL library.
avprobe
Gathers information from multimedia streams and prints it in human- and machine-readable fashion.
libavcodec
A library containing all the Libav audio/video encoders and decoders.
libavfilter
The substitute for vhook which allows the video/audio to be modified or examined between the decoder and the encoder.
libavformat
A library containing demuxers and muxers for audio/video container formats.
libavresample
A library containing audio resampling routines.
libavutil
A helper library containing routines common to different parts of Libav.

This library includes adler32, crc, md5, sha1, lzo decompressor, Base64 encoder/decoder, des encrypter/decrypter, rc4 encrypter/decrypter and aes encrypter/decrypter.

libswscale
A library containing video image scaling and colorspace/pixelformat conversion routines.

Contained codecs

Numerous free and open-source implementations of existing algorithms for the (usually lossy) compression and decompression of audio or video data, called codecs, are available. Please note that an algorithm can be subject to patent law in some jurisdictions. Here are lists of the ones contained in the libav library:

Video codecs

Libav includes video decoders and/or encoders for the following formats:[21]

Audio codecs

Libav includes decoders and encoders for the following formats:[26]

Supported file formats

Additionally to the aforementioned codecs, libav also supports several file formats which are designed to contain audio and/or video data and subtitles, called containers:

Supported protocols

Support for several communications protocols is also contained in libav. Here is a list:

  • IETF standards: TCP, UDP, Gopher, HTTP, RTP, RTSP and SDP
  • Apple related protocols: HTTP Live Streaming
  • RealMedia related protocols: RealMedia RTSP/RDT
  • Adobe related protocols: RTMP, RTMPT (via librtmp), RTMPE (via librtmp), RTMPTE (via librtmp) and RTMPS (via librtmp)
  • Microsoft related protocols: MMS over TCP and MMS over HTTP

See also

References

  1. ^ "Libav Home/News Page". libav.org. 2012-05-09. 
  2. ^ "Developer Documentation". libav.org. 2011-12-08. Retrieved 2012-05-17. 
  3. ^ "FATE". libav.org. Retrieved 2012-05-17. 
  4. ^ FFmpeg logo - FFMpeg mailing list, 20 Feb 2007
  5. ^ Legal Threat - ffmpeg.org 28 May 2011
  6. ^ FFmpeg License and Legal Considerations - ffmpeg.org, June 2011
  7. ^ "About Libav". libav.org. Retrieved 2014-11-30. ... which convinced us to fork "properly" under the name Libav with its own website, mailing lists, IRC channel and repositories, thus completely separating from the old FFmpeg project 
  8. ^ "Libav project site". libav.org. Retrieved 2012-01-04. 
  9. ^ Ronald S. Bultje (2011-03-14). "Project renamed to Libav". gmane.org. Retrieved 2012-01-04. 
  10. ^ "A group of FFmpeg developers just forked as Libav". phoronix.com. Phoronix. 2011-03-14. Retrieved 2012-01-04. 
  11. ^ "What happened to FFmpeg". multimedia.cx. 2011-03-30. Retrieved 2012-05-19. 
  12. ^ "FFMpeg turmoil". lwn.net. 2011-01-19. Retrieved 2012-01-04. 
  13. ^ "transition: Libav 0.7". debian.org. 2011-05-01. Retrieved 2012-01-04. 
  14. ^ """Ubuntu Release Management: Transition: "libav. canonical.com. Retrieved 2012-01-04. 
  15. ^ http://packages.gentoo.org/package/virtual/ffmpeg
  16. ^ "libav in AUR". aur.archlinux.org. Retrieved 2013-03-30. 
  17. ^ "Supported File Formats and Codecs". libav.org. Retrieved 2014-05-04. 
  18. ^ "Libav License and Legal Considerations". libav.org. Retrieved 2014-05-04. 
  19. ^ a b "FFmpeg/Libav Summer of Code". multimedia.cx. Retrieved 2012-05-19. 
  20. ^ "General Documentation". libav.org. Retrieved 2012-05-19. 
  21. ^ a b c d e f g banan (17 April 2007). "Changelog". mplayerhq.hu. Retrieved 26 April 2007. 
  22. ^ http://git.libav.org/?p=libav.git&a=commit&h=50ea93158d4c480f64069e8bd1da388486dcf4ba
  23. ^ https://github.com/OpenHEVC/libav
  24. ^ a b ivo (7 May 2007). "FFmpeg development mailing list". mplayerhq.hu. Retrieved 24 December 2010. 
  25. ^ "General Documentation". libav.org. Retrieved 2012-05-19. 
  26. ^ "#210 (24bit flac encoding) - FFmpeg". Ffmpeg.org. Retrieved 2012-02-03. 
  27. ^ vitor (13 April 2008). "FFmpeg development mailing list". mplayerhq.hu. Retrieved 14 April 2008. 
  28. ^ vitor (30 March 2008). "FFmpeg development mailing list". mplayerhq.hu. Retrieved 30 March 2008. 
  29. ^ faust3 (21 March 2008). "FFmpeg development mailing list". mplayerhq.hu. Retrieved 21 March 2008. 
  30. ^ benoit (14 April 2008). "FFmpeg development mailing list". mplayerhq.hu. Retrieved 14 April 2008. 
  31. ^ ramiro (18 March 2008). "FFmpeg development mailing list". mplayerhq.hu. Retrieved 18 March 2008. 
  32. ^ banan (8 June 2008). "FFmpeg development mailing list". mplayerhq.hu. Retrieved 8 June 2008. 
  33. ^ "Page showing Libav snapshot VLC uses". videolan.org. Retrieved 2012-05-24. 

External links

  • Libav homepage
  • List of supported formats
  • Libav-based Projects (includes projects using FFmpeg)
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.