G.729 designates from the ITU-T described codec to the compression of language into digital signals. To telephone G.729 with VoIP connections assigned over e.g. over Internet.

Technical data

Hybrid compression procedure, on the investigation and transmission of language parameters, with a Vocoder in such a way specified, as well as difference information and following speech synthesis supports itself. The codec sets size, which it examines for languagetypical characteristics on Frames of 10 ms. These are seized in parameters for a later synthesis. Besides the codec difference information is passed devoted from the artificially generated and the actual signal. In a language package two Frames of 10 ms each land, whereby the Delay lies with approx. 25 ms.

Further G.729 language tracing lets go down, in order to save range. So that this does not sound on the receiver side like a break, the standard defines additionally a noise generator, which fills out such tracing.

For these reasons G.729 is very cpu time consuming - he needs about 50 MIPS. A something simplified, variant which was subject qualitatively in addition, easily represents G.729A, which needs 10.5 MIPS arithmetic performance.

The technical designation reads also "“Conjugate Structure Algebraic code Excited linear Prediction"” (CS-ACELP).

The codec uses usually a bit rate of 8 kbit/s, however also 6.4 is kbit/s and 11.8 kbit/s possible. The frequency spectrum enclosure thereby 300 to 3400 cycles per second, whereby by the coding concept only language data will akurat transfer, for example with the Analogtelefonie of used multi-frequency tones it can only insufficiently process.

G.729 is relatively insensitive in relation to package losses, which distinguishes it for VoIP. With the MOS G.729 achieves a felt quality of 3,98 of 5 points, whereby G.729A reaches 3.7 of 5 points.

See also

• Language codec
• http://www.vocal.com/g729d0.pdf

Articles in category "G.729"

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Related Websites

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• Asterisk G.729 Licensing - voip-info.org
  G.729 requires a license per channel unless it is used in pass-thru mode. ... The free G.729 implementation does not make any changes to Asterisk, ...


• G.729 - Wikipedia, the free encyclopedia
  G.729 is an audio data compression algorithm for voice that compresses voice audio in ... Standard G.729 operates at 8 kbit/s, but there are extensions, ...


• G.729 - Wikipedia, the free encyclopedia
  G.729 is an audio data compression algorithm for voice that compresses voice audio ... G.729 is mostly used in Voice over IP (VoIP) applications for its low ...


• G.729 Coding of Speech Signals at 8 kbit/s using Conjugate ...
  VOCAL Technologies modem/telephony software libraries include G.729 and G.729 Annex A speech coders optimized for execution on DSP architecture from leading ...


• Speech Vocoder: G.729 (G729), G.729A (G729A), G.729AB (G729AB ...
  GAO Research is the world leading provider of G.729, G.729A, G.729AB Vocoder software which encodes/decodes at 8 kbit/s using CS-ACELP with silence ...