Polycom^® Siren^™ 14/G 722.1C FAQs

Siren 14 passes the audio band between 50 Hz and 14000 Hz, with excellent quality. Since Siren 14 is a transform-based codec, and not a speech-model based codec, it handles music and natural sounds just as well as speech, and does not "break up" on non-speech signals like many speech-model based codecs.

The 50 Hz to 14 kHz bandwidth covers 100% of the energy in human speech - this is approximately the same bandwidth as offered by FM broadcast radio. This range also approximates the audible range for adults past the age of 30 (high-frequency hearing tends to decline with age).

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Yes, you can send two channels of Siren 14 audio to provide stereo. This requires double the bit rate of mono Siren 14.

To preserve phase differences between the channels, we suggest that samples taken at the same instant should be stored or transported together, for example according to RFC 3551.

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No. Siren 14 is an audio codec only.

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Other "free" audio codecs that we are aware of either make use of technology on which the patents have expired (principally PCM and ADPCM codecs), in which case they require far higher bit rates (typically at least 128,000 bits/s) to approach Siren 14 technology's performance, or they use techniques about which there is dispute as to whether they infringe on patents held by third parties.

To our knowledge, Polycom's Siren technology is the only modern state-of-the-art audio coding technology offered on royalty-free terms.

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At a given bit rate Siren 14 technology provides audio quality and latency very similar to, and often better than, these other codecs, while consuming 1/4 th to 1/20 th of the CPU cycles they require. This makes it possible to operate Siren 14 with a lower-cost, lower-power processor, to operate more channels of Siren 14 on a given platform, or to free up processor cycles for other jobs such as video processing.

As part of the G.722.1 Annex C standardization process, the ITU extensively tested Siren 14 against MPEG-4 AAC LD. The ITU tests showed that the audio quality of Siren 14 is better than that of MPEG-4 AAC LD at all bit rates. Siren 14 also offers the same or lower latency compared to AAC LD, and much lower computational complexity.

For a given bit rate and processor cycle budget, Siren is by far the most efficient high-fidelity audio codec technology in the world today; this is why it was chosen as the international standard ITU-T Recommendation G.722.1 Annex C.

As well, Siren 14 is offered royalty-free; the others are not.

The document Siren 14 Information for Prospective Licensees has details on Siren 14's audio quality and computation requirements, and summarizes the results of the independent tests of Siren 14 that were done in the ITU standardization process for G.722.1 Annex C.

You are invited to download a PC executable version of Siren 14 from Polycom's Web site, that you can use to test the quality of Siren 14 for yourself.

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No. We supply working ANSI C source code, but as we receive no royalty revenues we can't afford to help you with your implementation.

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Yes. Parties who want to use Siren 14 must take a license and comply with the terms of the license. Our license involves other terms besides royalty payments. If you use Siren 14 without a license you will be infringing on our patents and potentially our copyrights. (We don't require a license if you are just evaluating the codec before deciding to use it in your product.)

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Yes. You don't have to pay us one penny to use Siren 14. However, you do have to obtain a license from Polycom and comply with its terms.

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The main requirements are:

1. You must give Polycom credit for Siren 14 technology, by acknowledging in your documentation, some marketing materials, and (where appropriate) in your product's user interface that you are using the Polycom Siren 14 (ITU-T G.722.1 Annex C)
2. Your implementation must conform to and be interoperable with the ITU-T G.722.1 Annex C standard. Our goal is to encourage interoperability so that our customers will enjoy the benefits of super-wideband audio quality)
3. Don't sue us over your patents. If you sue us, the license terminates. In this case Polycom will still offer you Reasonable and Non-Discriminatory (but not free) licensing terms according to the ITU-T Patent Policy)

Please read the license itself carefully for full details.

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No. Polycom respects the patent rights of others. The termination provision is to provide a more appropriate setting in potential cross-licensing discussions.

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To our best knowledge and belief, no. Our belief is that all patents on Siren 14 technology are owned by Polycom. The algorithm is identical to that of ITU-T G.722.1 (Siren 7 audio technology), which has been in the market since 1998, and as of this writing (April 2005) no other party has claimed otherwise, even informally.

However, as with any technology, it is always possible that third parties may claim, correctly or not, to have rights that are infringed by Siren 14 technology. Ultimately only a court of law can decide the validity of such claims. Polycom offers no guarantees that no one will make such a claim in the future, and will not compensate licensees for losses resulting from any such claims. Licensees are responsible for their own risks in this regard.

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Polycom, as the world's leading provider of unified collaborative communications solutions including video conferencing and high-end teleconferencing equipment, seeks to expand our market by making telecommunications more effective, natural, and valuable.

By offering Siren 14 on royalty-free terms, we hope to encourage the widespread implementation and use of super-wideband quality audio that is standards-based and interoperable across all vendors, so that our customers will enjoy the ultimate in clear, natural-sounding audio.

Polycom is proud of our leadership positions in media coding technology and standardization, and by making Siren 14 available royalty-free we have an opportunity to demonstrate our superior technology and industry leadership to the widest possible audience.

Finally, we do require that licensees give Polycom credit for our Siren™14 technology in their documentation, some marketing materials, and (where appropriate) their user interface (please see the license for details). In the current environment we believe that this exposure of Polycom's technology and name provides us with significant value.

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Please send an email to sireninfo@polycom.com.

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Both Siren7 and Siren14/G.722.1 and G.722.1 Annex C technologies are now offered on royalty-free terms as described above. The license agreement with Polycom covers Polycom’s IP as implemented within both of these standards, as well as within ITU-T G.719, the new fullband (20kHz) codec.

Please see the "Siren 7" section of Polycom's Web site for more information regarding Siren7, and the ITU Web site itself for information regarding G.719.

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The standard is formally known as ITU-T Recommendation G.722.1 Annex C, and is published by the International Telecommunications Union (ITU) in Geneva, Switzerland as a part of G.722.1.

You can obtain a copy from ITU at their Web site:

http://www.itu.int/rec/recommendation.asp?type=items&lang=e&parent=T-REC-G.722.1-200505-P

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