Skype unfurls a royalty-free SILK codec

At eComm on Tuesday, Skype announced that it'll make its SILK wideband codec available royalty-free to third-party developers. The release gives Skype a shot at solidifying its lead in the VoIP race and should increase consumers' exposure to, and desire for, wideband-quality call quality.

SILK, which debuted to positive reviews in the 4.0 version of Skype for Windows released last month, is Skype's default audio codec for Skype-to-Skype calls. It scales its bandwidth usage in real time between 6 Kpbs and 40 Kbps, and in "superwideband" (best) mode samples at 24 KHz. Likewise, bit rate scales from 6-40 Kbps as dictated by connection conditions.

The data sheet, which includes test results from the Dynastat labs comparing SILK with rival codecs Speex and AMR Wideband, is available as a PDF file. Charts of those test results indicate that SILK managed to maintain relatively high sound quality even at high (10%) levels of packet loss.

Despite scattered grumbling about Skype's slow rollout of SILK to its very own clients -- a Mac version isn't expected until April -- the announcement has been generally received with excitement, as well as questions about whether the SILK release presages greater openness for the service's core protocols. (SILK does not require Skype's signaling protocols. In fact, it doesn't require Skype at all.)

Interested developers should consult Skype's SILK page for details on getting access to the SDK.