Jonathan Christensen of Skype announced in March 2009 at eComm the royalty free licensing of its super-wideband codec, SILK. To this end, all Skype calls to +883 iNum numbers are now available in high definition.
Skype’s user base of 480 million users brings HD calling to all of inum’s partner networks. From retail users to enterprises, call centers to call conferencing services and not forgetting the plethora of innovative voice applications available through Voxeo: using iNum they can all be reachable from Skype’s new HD platform.
High definition is made possible because such calls do not travel over the PSTN, ensuring end-to-end wideband capability. The PSTN supports 8,000 audio samples per second, whereas the new SILK codec supports between 16,000 and 24,000 samples per second. This greater sampling rate enables the caller to hear more detail in the conversation: regional dialects and subtle consonantal sounds are represented more clearly on a HD call.
Background noise however is also more easily picked up, and this is why HD requires a better quality microphone and speaker set than traditional PSTN telephony. For HD to work, all components on the voice path need to support high definition.