veyepar: Codec 2 - Open Source Speech Coding at 2400 bit/s and Below

Author(s):	David Rowe
Location	Studio
Date	jan Tue 17	Days Raw Files
Start	15:40	First Raw Start	error-in-template
Duration	0:50:00	Offset	None
End	16:30	Last Raw End
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Total cuts_time	None min.

http://lca2012.linux.org.au/schedule/59/view_talk
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assets release.pdf Codec_2_Open_Source_Speech_Coding_at_2400_bits_and_Below.json
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Codec2 is an open source low bit rate speech codec designed for communications quality speech at around 2400 bit/s. Applications include low bandwidth HF/VHF digital radio and VOIP trunking. Codec 2 operating at 2000 bit/s can send 32 phone calls using the bandwidth required for one 64 kbit/s uncompressed phone call. It fills a gap in open source, free-as-in-speech voice codecs beneath 5000 bit/s and is released under the GNU Lesser General Public License (LGPL).

Speex and the other open video and audio codecs have proven it’s possible to create a patent free, high quality codec. There is an important social theme behind these technical projects. A free codec helps a large amount of people and promotes development and innovation. A closed codec helps a small number people make money at the expense of stifled business and technical development for the majority.

One important part of Codec 2 is the use of open source and community development techniques. The net result was access to a world wide "brains trust" and network of beta testers that has resulted in swift development of effective DSP algorithms.

This presentation will explain the advanced DSP techniques used in Codec 2 in terms the average Linux user can understand, plus give examples of end user applications.

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