HD Voice Increases Call Duration, Says Skype

Jonathan Rosenberg, Skype chief technology strategist, says high-definition call quality can increase the length of a voice call 45 percent. That, in turn, could theoretically lead to higher revenues for application or service providers whose services are sold "by the minute." Call duration might have no revenue implications at all if the endpoints are talking on a "no incremental cost" basis, though.

Skype's studies suggest, as you would expect, that audio quality is higher on a high-definition call. The Skype survey suggests there is a correlation between call audio quality and call duration.

With the lowest quality, approximating mobile call quality, the average call lasted about 21.5 minutes. At the highest quality it went about 31 minutes.

It's difficult to say whether the relationship is correlational or causal, though. One variable might be that users on the highest-quality codecs are predisposed to use Skype for conferencing sessions, which would have call duration parameters quite different from a casual voice conversation between two people, for example.