G.722.1

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G.722.1 is a specialized to speech signals Transformations - Codec for lossy audio data compression . It is based on the Siren 7 process , which was developed by Polycom , Inc. (then PictureTel Corporation ) and contains technologies patented by the company . Usage licenses are granted free of charge.

The codec works with a frequency transformation with overlapping blocks, the so-called Modulated Lapped Transform (MLT). It works with a sampling rate of 16 kHz and maps frequencies of up to 7 kHz ("broadband") in data streams of 24 or 32 kbits per second. The computation effort (algorithmic complexity) is about 5.5 M IPS (with floating point arithmetic). The algorithmic transmission delay is 40 milliseconds.

The predecessor of the process was PT716plus. The Telecommunications Standards Department of the International Telecommunication Union (ITU-T) adopted the procedure on September 30, 1999 as the officially recommended international standard. Annex C of the standard, which was passed on May 14, 2005, describes a broadband variant that can map a frequency range of up to 14 kHz. It is a purely monophonic variant of Siren 14. In 2008 the ITU-T passed the further development G.719 .

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