[snarkinatree]

How about "Skype: The Missing Technical Manual"?

MS will contribute nothing to the state of the art of free voice and video calls over the internet. As is so often the case, what they purchased with the Skype deal was a user base. One that they could never obtain with the own products.

There is a way to do this without violating copyright.

Do not waste time duplicating the P2P element of Skype (the P2P protocol). P2P protocols have been done, several ways, some of them are easily good enough, maybe even smarter than Skype's (e.g., avoiding the exposure of your IP to the entire internet) and enough of the code is GPL'd or BSD licensed to keep things open. We have ample solutions for P2P. View that as the "open platform".

Now you need "apps" to run on it. First one is a softphone, but with Skype's codecs.

Focus on creating a standalone softphone using Skype's codecs.

Does MS have exclusive rights (patent rights) on Skype's codecs? Not even close. They did not develop them. The patent license could fit on a single page; it's as simple as they come: build stuff, pay nothing.

http://developer.skype.com/silk

[danbmil99]

If you don't want to be compatible with Skype, you don't need their codecs. There are plenty of good voice codecs around, freely licensable.

The issue is how to tap into the existing Skype userbase -- receive and make calls to Skype clients -- from an open-source client.

[snarkinatree]

I agree tapping into the existing userbase is enticing. And that's no doubt what some people are trying to do (e.g. the Russians).

But all VOIP codecs are not created equal. Skype's success is not due to NAT piercing. Even though Skype easy to use, maybe easier than previous SIP alternatives, if calls sounded terrible, people would not use it. Skype's success is due to being usable and having decent sound quality. They did not use the decades old codecs other softphones used. They wrote new ones. And anyone can use them.

Using the same codec as Skype uses should not in any way bind you to their network. It has nothing to do with compatibility. It has to due with getting Skype-level sound quality. Quality that the older codecs have failed to deliver.

It's easy to get people to sign up for free voice and video calls. The key word is "free". You do not have to find inroads into the "Skype user base". Skype spread by word of mouth. If people learn about another client that works as well or better (same sound quality), and it's easy to use, they will almost certainly try it.

Forgive me if I have misunderstood what you were trying to say in your comment. But I do not understand your reasoning.

[jahewson]

Yes, they purchased users, but also a lot of patents which go far beyond codecs http://www.google.com/search?tbm=pts&tbo=1&hl=en&...