Polycom^® Siren^™/G 722.1

G.722.1 is a state-of-the-art international standard wideband audio compression algorithm. It is based on the third-generation of Polycom Siren compression technology and is derived from Polycom's field-proven PT716plus algorithm. Polycom developed this technology to meet the demanding audio needs of the multimedia community. It provides high-quality audio at low bit rates with low delay and very low complexity. It works for all kinds of audio signals including speech, music, and singing, for example.

G.722.1 provides wideband audio, closer in quality to FM radio than to ordinary telephone.

For example, in a telephone conversation, have you ever misheard the words "see" and "fee"? The "f" and "s" sounds are easily confused because their intelligibility is lost with inadequate rendering of the high frequencies. Such confusion never occurs with wideband coding, because all the frequencies required for speech are now fully represented. The whole audio experience when using wideband is far more natural and relaxing to the ears.

Because of its low complexity (~ 14 fixed-point MIPS, ~ 2 to 9 floating-point MIPS), G.722.1 may be used on a variety of processing platforms from digital signal processors (DSPs) to host CPUs, and still leave ample cycles for other process-hungry tasks.

The G.722.1 standard specifies operation at 24 kbps and 32 kbps for wideband (50 Hz - 7 kHz) and is currently defined in the form of a fixed-point arithmetic implementation. In addition, all licensees also get Polycom's 16 kbps extension of the standard.

Until now wideband coding was only possible using ITU-T Recommendation G.722 (at double the bit rate of G.722.1) or a proprietary algorithm. This is a big bandwidth saving in any wideband application, and it opens a whole new world of applications.

Examples of G.722.1 and Polycom Siren at 16 kbps applications:

• Wideband IP telephony
• Streaming audio (including music!) over the Internet
• Video conferencing
• Audio conferencing
• Audio storage playback (recorders)
• Store-and-forward messaging (voice mail)
• Audio-enabling your Web site