What? like https://www.zoiper.com/en/voip-softp...wnload/current

Or

https://www.viber.com/

Everything else is Windows Store centric. Something I could not use. Or my nieces on their phones.
So I went with what I know. Open source with source code links.

https://github.com/jitsi

Funny you mention google talk. Then dis it.

Why to consider JITSI? I is just anyhow a gate for Google talk (Hangouts). It is probably better to use Hangouts directly on the mobile phone. But, if you don't have a Gmail account, people are screwed. In other words, you use google and NSA is really happy.

SIP? No one in the windows world consider SIP, because it is too complicate to configure. You have SIP and can call yourself, because no one can use it. Firewall?

Immediate family on Windows and Android understand on how to use it.

A consideration I guess you don't require in this thread.

It should be free, opensource, easy to compile, ideally based on QT or simple portable graphic lib, easy signin (easy for all humans) from the software itself, compiled on Android, mac, win, unix-like systems,... avoid spyware, respect users not like Google, Viber,..., firewall pass,... and in terms of features, just audio (with echo correction) and video.

Discord is not good for serious use and is coded very badly. Plus the screensharing/video calling doesn't work for some people because it is completely powered by a UI-less Chrome, basically.

That said, I'm also hoping for a serious, FOSS replacement for Skype, especially if it can be one that is cross-platform and works decently enough with the mobile market.

Discord is deprecated.

By the end, the best of the best was really Skype, so far, we can see from this thread.

Just curious... by "the best was Skype", do you mean before Microsoft absorbed it? Also is part of your criteria the ability to ring some manner of physical phones to accept calls?

Skype was good, likely the best VOIP software, because of the quality of echo cancelling mostly. Rest of features, included its "closed source", made it what it was.

How does "closed source" make it better? Please don't misunderstand me. I applaud that the GPL makes room for coexistence with proprietary for some things (example: nvidia drivers, if open source, could reveal information about hardware that the company needs insurance stay protected, if not secret) but I really don't see that applying to something as mundane as echo cancellation. It seems to me that if Skype was so much better, Windows phones would own that market and instead, they kinda suck, and are far from even being a close 3rd.

I have used Vonage phone service for over 5 years and the quality difference to a land line is undetectable and I have a highly trained ear having worked as an audio engineer and musician for over many decades. I've used TeamSpeak, Ventrillo, RaidCall, as well as Skype and many other smaller VOIP apps in groups where people were spaced all around the globe and not heard that Skype was any better than any other. In fact some of those apps had more control over the algorithm than Skype, even back before Skype became a household word.

To me that is the best that Skype offered, recognition and popularity in a common app making it somewhat easier to connect to others who also have the app, but even that doesn't have to be essential.

- You're actually right. TeamSpeak, Ventrillo, RaidCall, ... are definitely good softwares.
- "household word": in universities and at work, it is often that Skype is installed. Skype has become a widely accepted "standard" for phone calls. Many companies still use Skype (*unfortunately*).