Skype SILK codec set free-as-in-beer

In Wednesday's IT Blogwatch, Richi Jennings watches Skype open up its fancy new voice encoding technology. Not to mention London Underground: run by people, not androids...

Stephen Lawson reports:

Skype logo
Skype will license a high-quality audio codec in its latest VoIP (voice over Internet Protocol) software to any developer or vendor free of charge, the eBay subsidiary announced Tuesday.

The codec, called Silk, can deliver sound quality that captures the full sound of the human voice, according to Jonathan Christensen, Skype's general manager of audio and video. This "super-wideband" codec was introduced with the Skype 4.0 for Windows client, announced last month. Christensen unveiled the licensing program, which is live now, at the eComm conference in Burlingame, California.

Brad Linder adds:

Voice over IP company Skype is known for a couple things. One of them is annoying the #@&! out of telephone companies by offering cheap or free voice and video calls over the internet. But another thing that Skype does well is offer users the ability to communicate across long distances with excellent sound quality.


That's because typically telephones only transfers audio signals in a limited frequency range (from around 400Hz to 3.4kHz). Skype, on the other hand, uses technology that can transmit audio up to 12kHz ... if you're using decent audio equipment you'll sound like you're in the same room ... even over low bandwidth internet connections. And now Skype is making that codec available for other companies to use, with no royalties.

Skype's Jonathan Christensen celebrates:

Today marks a significant moment in the journey of Skype ... SILK is Skype’s signature super wideband audio codec which achieves super wideband audio quality using 50% less network bandwidth than previously required. It is the outcome of a three year long development process in the Skype labs, which focused on four things:

  • improving audio bandwidth going from 8 kHz to 12 kHz...
  • providing real-time bandwidth scalability to deal with degraded network conditions
  • balancing codec optimization between voice, music and background noise...
  • delivering a robust solution that delivers a more consistent audio experience.

My, Phil Wolff, what big eyes you have:

Skype spent millions buying the talent and building the technology behind SILK. Why would Skype give up a competitive edge? I can think of a short term reason and longer term one.

Short term, Skype needs gear built to support the high fidelity of the Skype network. When SILK is comes on mobile phone chips, for example, Skype won't have to consume as many CPU cycles, chew up as much power, or run as hot ... Longer term, Skype's platform strategy calls for interop. To make that work, Skype will need to make available some of the components you find in a Skype client.

Alec Saunders calls it a bear hug:

If all goes according to Skype’s plan – you won’t need to be at your PC anymore to experience Skype audio quality. Instead, SILK will be built into all kinds of audio devices. It’s a great plan ... with 405 million Skype installations to back it, SILK has far more chance at being ubiquitous than say, any other high definition codec.


The criticism levelled at all “high definition” audio schemes is that both parties have to use these services in order to achieve the benefit.  Making SILK ubiquitous is the way to make that happen ... For once, manufacturers have an incentive to simply include a wideband codec on every product they sell ... SILK doesn’t require Skype signalling protocols. In fact, SILK media streams could just as easily be originated and consumed by SIP devices.

Jim Courtney agrees:

I have watched as a wireless carrier attempts at new video calling services are introduced and subsequently fail due to a lack of adoption – the primary reason being there are too few devices out there supporting video calling and thus, there’s nobody to whom one can make a wireless video call.

Skype’s announcement today overcomes a major barrier to allowing a much broader user base to take advantage of superwideband audio. It’s a first, but key, step towards  ... superwideband audio on all voice calling.

Michael Arrington muses:

Skype, with 400 million or so worldwide registered users, isn’t particularly concerned about the competition any more. They’re handing over a key piece of intellectual property to competitors that can reduce their costs and possibly improve voice quality. They wouldn’t do that unless they felt their pole position was fairly permanent for now.

More importantly, it signals that Skype may be preparing to open up their service in the future. Skype has long been derided for being a closed service (by people like me, who continue, however, to use it daily). Their API allows developers to access limited features of the service, but a call requires the opening of the Skype client. If Skype were to open its core calling functions as a service, the number of applications that would build it in would explode. Skype would benefit from a surge in paid calls to traditional and mobile phones (Skype Out). Our guess is that the debate to open these core functions through the API is still raging within Skype, but that the proponents of openness are slowly starting to turn the tide.

And finally...

Previously in IT Blogwatch:

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Richi Jennings is an independent analyst/adviser/consultant, specializing in blogging, email, and spam. A 23 year, cross-functional IT veteran, he is also an analyst at Ferris Research. You can follow him on Twitter, pretend to be Richi's friend on Facebook, or just use boring old email:

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