From Wikipedia, the free encyclopedia Siren (codec)
Siren (codec)
Siren is a family of patented, transform-based, wideband ceiving voice clips and also as one of the available codecs
audio codecs developed and licensed by PictureTel Cor- for the ’Computer Call’ feature.[11][12][13]
poration (acquired by Polycom, Inc. in 2001).[1] There are FreeSWITCH communication open source software
three Siren codecs: Siren 7, Siren 14 and Siren 22. can do transcoding, conferencing and bridging of Siren
Siren 7 (or Siren7 or only Siren) provides 7 kHz audio, 7/G.722.1 and Siren 14/G.722.1C audio formats.[14][15][16]
bit rates 16, 24, 32 kbit/s and sampling frequency 16 kHz. aMSN, an open source Windows Live Messenger clone
Siren is derived from PictureTel’s PT716plus algorithm.[2] uses for Siren audio compression and decompression the
In 1999, ITU-T approved G.722.1 recommendation, which "libsiren" library, an open source implementation of the
is based on Siren 7 algorithm. It was approved after a codec, written by aMSN developer Youness Alaoui
four-year selection process involving extensive test- (KaKaRoTo) .[17] The libsiren library has also been copied
ing.[2] G.722.1 provides only bit rates 24 and 32 kbit/s and into libmsn and into the msn-pecan project, which pro-
does not support Siren 7’s bit rate 16 kbit/s.[3][4] The al- vides plug-in for Pidgin and Adium instant messaging
gorithm of Siren 7 is identical to its successor, G.722.1, al- clients.[17][18][19][20][21]
though the data formats are slightly different.
Siren 14 (or Siren14) provides 14 kHz audio, bit rates
24, 32, 48 kbit/s for mono, 48, 64, 96 kbit/s for stereo
Licensing
and sampling frequency 32 kHz. Siren 14 supports stereo Usage of Siren 7 and Siren 14 compressions require the
and mono audio. It offers 40 millisecond algorithmic de- licencing of patents from Polycom, in most countries. A
lay, using 20 millisecond frame lengths. The mono ver- royalty free licence for Siren 7 and Siren 14 is available
sion of Siren 14 became ITU-T G.722.1C (14 kHz, 24/32/ from Polycom if certain fairly basic conditions are
48 kbps) in April 2005.[5][6][7] The algorithm is based on met.[4][15][22][23][24][25][26]
transform technology, using a Modulated Lapped Trans- Usage of Siren 22 also require the licencing of patents
form (MLT).[8] from Polycom.[24]
Siren 22 (or Siren22) provides 22 kHz audio, sampling
frequency 48 kHz, bit rates 64, 96, 128 kbit/s stereo and
32, 48, 64 kbit/s mono. Siren 22 offers 40 millisecond al-
See also
gorithmic delay using 20 millisecond frame lengths. In • Comparison of audio codecs
May 2008, ITU-T approved the new G.719 full-band codec • G.722.1
which is based on Polycom Siren 22 audio technology and
Ericsson’s advanced audio techniques.[9][10] References
[1] Business Wire (2001-03-26). "PictureTel Announces
Software support New Siren Wideband Audio Technology Licensing
Siren 7 is commonly used in videoconferencing systems Program". thefreelibrary.com.
and is also part of Microsoft Office Communicator when http://www.thefreelibrary.com/
using A/V conferencing. Microsoft Office Communica- PictureTel+Announces+New+Siren+Wideband+Audio+Technology+
tions Server uses Siren 7 during audio conferencing. With a072261882. Retrieved 2009-09-10.
the default Office Communicator client, point to point [2] ^ Business Wire (2000-07-19). "PictureTel Licenses
audio is by default performed using Microsoft’s propri- Audio Technology Suite to Intel".
etary codec RTAudio. When a call is promoted into an thefreelibrary.com.
audio conference (any time 3 or more participants have http://www.thefreelibrary.com/
joined), the codec is switched on the fly to Siren. This is PictureTel+Licenses+Audio+Technology+Suite+to+Intel.-
done for performance reasons. Note that even if the con- a063558475. Retrieved 2009-09-10.
ference is reduced to below 3 participants, OCS does not [3] (2008-08-05) Polycom Enables Acceleration of HD
demote the conference to be point-to-point; it remains Voice Adoption by Offering Royalty-Free Codec,
an A/V conference until the conference is terminated. Retrieved 2009-09-07
In Windows XP and later versions of Windows, the [4] ^ "Polycom Siren/G 722.1 FAQs". Polycom, Inc..
Siren 7 codec is implemented in %system- http://www.polycom.com/company/about_us/
root%\system32\SIRENACM.DLL. It is used by technology/siren_g7221/faq.html. Retrieved
MSN Messenger and Live Messenger for sending and re- 2009-09-07.
1
From Wikipedia, the free encyclopedia Siren (codec)
[5] Polycom, Inc. (2005-04-12) ITU Approves Polycom [17] ^ KaKaRoTo (2008-02-12) MSN Protocol
Siren14 as New International Standard, Retrieved documentation, Pidgin.im mailinglist, Retrieved
2009-09-07 2009-09-08
[6] "Polycom Siren 14/G 722.1C". Polycom, Inc.. [18] "msn-pecan 0.0.18 released, now with voice clips
http://www.polycom.com/company/about_us/ support". msn-pecan. 2009-02-16.
technology/siren14_g7221c/index.html. Retrieved http://felipec.wordpress.com/category/
2009-09-07. development/page/2/. Retrieved 2009-09-07.
[7] "ITU Approves Polycom Siren14 as New [19] "msn-pecan". msn-pecan. http://code.google.com/
International Standard". BusinessWire.com. p/msn-pecan/. Retrieved 2009-09-07.
2005-04-12. http://www.businesswire.com/portal/ [20] "Libmsn - is a reusable, open-source, fully
site/home/permalink/ documented library for connecting to Microsoft’s
MSN
?ndmViewId=news_view&newsId=20050412005325&newsLang=en.Messenger service.". Libmsn project at
Retrieved 2009-09-10. Sourceforge.net. 2009. http://sourceforge.net/
[8] Siren 14 information for Prospective Licensees, projects/libmsn/. Retrieved 2009-09-07.
http://www.polycom.com/global/documents/ [21] "SCM Repositories - libmsn - libsiren". Libmsn
company/about_us/technology/siren14_g7221c/ project at Sourceforge.net. 2009.
info_for_prospective_licensees.pdf, retrieved http://libmsn.svn.sourceforge.net/viewvc/libmsn/
2010-06-08 trunk/msn/libsiren/. Retrieved 2009-09-07.
[9] "Polycom Siren 22". Polycom, Inc.. [22] Xiph.Org Foundation (2009). "CELT - Codec Feature
http://www.polycom.com/company/about_us/ Comparison". Xiph.Org Foundation.
technology/siren22/index.html. Retrieved http://www.celt-codec.org/comparison/.
2009-09-07. Retrieved 2009-09-07.
[10] "G.719: The First ITU-T Standard for Full-Band [23] Xiph.Org Foundation (2006). "Speex - Codec Quality
Audio". Polycom, Inc.. 2009-04. Comparison". Xiph.Org Foundation.
http://www.polycom.com/global/documents/ http://www.speex.org/comparison/. Retrieved
whitepapers/g719-the-first-itut-standard-for-full- 2009-09-07.
band-audio.pdf. Retrieved 2009-09-07. [24] ^ Polycom, Inc.. "Siren7/Siren14/G.719 License
[11] "Siren". MultimediaWiki. info". Polycom, Inc.. http://www.polycom.com/
http://wiki.multimedia.cx/index.php?title=Siren. company/about_us/technology/siren_g7221/
Retrieved 2009-09-07. license_schedule.html. Retrieved 2009-09-07.
[12] "MPlayer - Status of codecs support". [25] Polycom, Inc.. "Polycom Siren 14/G 722.1C FAQs -
MultimediaWiki. http://www.mplayerhq.hu/ What are the terms on the free license?". Polycom,
DOCS/codecs-status.html#ac. Retrieved Inc.. http://www.polycom.com/company/
2009-09-07. about_us/technology/siren14_g7221c/
[13] Microsoft (2001-11). "Media Support in the faq.html#license_q3. Retrieved 2009-09-07.
Microsoft Windows Real-Time Communications [26] Greg Galitzine (2008-08-06). "Polycom CTO
Platform". Microsoft. http://msdn.microsoft.com/ Discusses Siren 7 HD Voice Codec". TMCnet.com.
en-us/library/ms997607.aspx. Retrieved http://hdvoice.tmcnet.com/topics/wideband-
2009-09-07. audio/articles/36272-polycom-cto-discusses-
[14] "FreeSWITCH First to Support Polycom’s 32khz HD- siren-7-hd-voice-codec.htm. Retrieved 2009-09-07.
Audio.". FreeSWITCH. 2008-12-15.
http://www.freeswitch.org/node/153. Retrieved
2009-09-07.
External links
[15] ^ "libg722_1 - COPYING". FreeSWITCH. • Polycom Siren/G 722.1
http://svn.freeswitch.org/svn/freeswitch/trunk/ • Polycom Siren/G 722.1 FAQs
libs/libg722_1/COPYING. Retrieved 2009-09-07. • Polycom Siren 14/G 722.1C
[16] "libg722_1 - README". FreeSWITCH. • Polycom Siren 22
http://svn.freeswitch.org/svn/freeswitch/trunk/
libs/libg722_1/README. Retrieved 2009-09-07.
Retrieved from "http://en.wikipedia.org/w/index.php?title=Siren_(codec)&oldid=437253042"
Categories:
• Audio codecs
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From Wikipedia, the free encyclopedia Siren (codec)
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