Why did Skype publish SILK's source code?

Voxeo's Dan York shows Skype released the source code to its SILK super wideband audio codec to the "CODEC Working Group" of the Internet Engineering Task Force, one the Internet's standards bodies. SILK is one of the things that make Skype calls sound so rich and vivid. And now SILK is available for everyone. Jim Courtney reviews SILK's history and lists its early adopters on the way to becoming a freely licensed Internet standard.

Why is Skype doing this?

I think this goes to two issues: adoption and competitive advantage.

Skype got all kinds of grief for keeping SILK proprietary and out of the public domain. That's a barrier to adoption when there are other wideband audio codecs with less encumbered licenses. So publishing the source should, in theory, make this easier for companies and governments, big and small, to choose SILK. SILK is not in the lead when I asked operators at a CES wideband audio session whether they were interested. So anything Skype can do to make it more attractive is a good thing.

As for competitive advantage, Skype's advantage in talk audio and video quality over other VoIM operators (Microsoft, Yahoo!, AOL) disappeared when GIPS licensed their wideband codecs. Skype's advantage is really in the network effects (that more people have Skype dialtone than other networks).

So how do you put SILK to use? First, you make it a benefit of partnering with Skype. Make your embedded and mobile hardware sound better or use less bandwidth. Offer wideband audio at narrowband prices. You're free to do this without Skype, but why not take advantage of Skype's global marketing power and be the device/operator that not only sounds good but sounds good with Skype? Imagine that you're a smart television maker; this would be one more reason to pre-install Skype codecs.

One last competitive advantage point: consumers don't care about which codec gives them HD audio/video. Skype doesn't much care either. What matters to Skype is that you define who they are competing against. Their grand enemy/obstacle/incumbent/dominator isn't Microsoft or Google or Logitech or Apple. It's the local and long distance carrier. So anything which helps Skype develop allies that make the PSTN look slow, decrepit, and obsolete positions Skype favorably by comparison.

tags: skype, silk, ietf, codecs, open source

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