Proved to myself that sound under Linux still sucks as bad as it did last year during some weekend testing of SIP and XMPP based “alternatives” to Skype. Of course the fractured nature of Linux sound isn’t the only problem with these supposed solutions, but it definitely doesn’t help.
Background noise and poor to non-existent automatic gain control are at the top of the list for things that didn’t work as required in my testing, which was focused mainly on using the Java-based Jitsi client to do voice and video over SIP and XMPP.
Apart from audio input issues, which persisted even after switching from the default Pulse subsystem to the one that used ALSA (by way of comparison the latest Skype also uses Pulse, but interposes its own proprietary noise suppression and gain control), the main services I used for SIP testing, iptel.org and ippi.fr, were far from consistent in their signal quality. In most cases they were actually very poor. In voice-only tests my primary carrier, Callcentric, did much better (Callcentric does not support video calls yet), but all of the clients I tried on Linux still had the same audio input issues even with the high quality connections that Callcentric delivered. Results even through my home XMPP server were also disappointing for the same reason.
Because moderately good audio quality is especially important in voice calling that means that none of these services are going to replace Skype as my Linux desktop VOIP solution any time soon. That’s a damn shame because like so many others I really would like to move off Skype and onto something a bit more privacy friendly.