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G.729, G.722, and G.723.1

G.729, G.722, and G.723.1[1] are audio codecs with software patent problems. They are used primarily in telephony.

Transcoding to and from (i.e. encoding and decoding) these formats is thought to be covered by a patent.

Some other uses of these formats are outside the scope of the patent. For example, the Asterisk PBS software has a "pass-thru" mode which transports G.729 audio without transcoding it, and this is considered safe from patent risk.[2]

Projects harmed by these patents include freeSWITCH[3] and Asterisk PBX.

Related pages on ESP Wiki

External links


  1. "0005697: Choppy Audio When Using > 20 MS Audio Frames". "The G.723.1 codec is not distributed with Asterisk, as it is under patent protection." 
  2. "0005084: [patch Simple G.722 pass-through addition"]. "Patent issues doesn't matter, because tihs code not add transcoding.This support done like G.729 support." 
  3. "Re: [sipX-dev Critical Problem : No MOH on transfer when G729 is selected on call setup."]. "Why is G729 not enabled by default for freeSWITCH ? ... One word: Patents"