Wideband codecs and IPR

Wideband codecs are a good thing. They have been slow to enter the mainstream, but there are several reasons why this is about to change.

Voice codecs are benefiting from the usual good effects of Moore’s law. Each year higher-complexity (higher computation load) codecs become feasible on low-cost hardware, and each year it is cheaper to fit multiple codecs into a ROM (adding multiple codecs increases the chance that two endpoints will have one in common).

Voice codecs are often burdened by claims of intellectual property rights (IPR) by multiple players. This can make it difficult for software and equipment vendors to use codecs in their products without fear of litigation. The industry response has been to create “patent pools” where the patent owners agree to let a single party negotiate a blanket license on their behalf:

Prior to establishment of the Pool, the complexity of negotiating IPRs with each intellectual property owner discouraged potential integrators.

Unfortunately there is still no pool for the standard wideband codec ratified by the 3GPP for use in cell phones, AMR-WB (G.722.2). Even where there is a pool, getting a license from it doesn’t mean that a use of the codec doesn’t infringe some yet-to-be-revealed patent not in the pool, and it doesn’t indemnify the licensee from such a claim.

There are several royalty-free wideband codecs available. I mentioned a couple of them (from Microsoft and from Skype) in an Internet Telephony Column.

Microsoft and Skype have got around the royalty issue to some extent by creating proprietary codecs. They have researched their algorithms and have either concluded that they don’t infringe or have bought licenses for the patents they use.

G.722 (note that G.722, G.722.1 and G.722.2 are independent of each other, both technically and from the point of view of IPR) is so old that its patent restrictions have expired, making it an attractive choice of common baseline wideband codec for all devices. Unfortunately its antiquity also means that it is relatively inefficient in its use of bandwidth.

Polycom did a major good thing for the industry when it made G.722.1 (Siren7) available on a royalty-free basis. G.721.1 is considerably better than G.722, though it is not as efficient as G.722.2.

The open-source Speex codec is efficient and royalty free, but being open source it bears a little more fear of infringement than the other codecs mentioned here. There are three reasons why this fear may be misplaced. First, the coders claim to have based it on old (1980’s) technology. Second, it has now been available for some years, and has been shipped by large companies and no claims of infringement have surfaced. Third, while it is possible in these times of outrageous patent trolling that somebody will pop up with some claim against Speex, a similar risk exists for all the other codecs, including the ones with patent pools.

So we now have three royalty-free wideband codecs (G.722, G.722.1 and Speex); we have hardware capable of running them cheaply; we have broad deployment of VoIP and growing implementation of VoIP trunking. We have increasing data bandwidth to homes and businesses, to the point where the bandwidth demands of voice are trivial compared to other uses like streaming video and music downloads. Plus there’s a wild card. By 2010 over 300 million people will have mobile smartphones capable of running software that will give them wideband phone conversations over a Wi-Fi connection.

Perhaps the time for wideband telephony is at hand.

4 Replies to “Wideband codecs and IPR”

  1. Michael,

    Have you had a look at the new CELT codec being developed by Xiph.org? It claims to support, amongst other things, sample rates as high as 48 khz in bit rates from 48 kbps.

    It’s from the same group responsible for Speex. I wonder if it might achieve greater acceptance, or if such efforts are doomed to limited uptake by commercial entities?

    Michael Graves

  2. Xiph.org codecs are released under Xiph’s version of the (revised) BSD license, which means that you can distribute them provided you include a notice in the documentation.

    There is no patent pool for G.722.2 (AMR-WB). Each of the companies that currently claims patent rights on AMR-WB (VoiceAge, Nokia and Ericsson) must be negotiated with individually.

    Wideband versions of G.711 and G.729 are licensed from Sipro.

    None of these (xiph, VoiceAge, Sipro, Nokia, Ericsson) appear as members of IPsupermarket.com.

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