Currently, it is impossible with current ebuild to install net-im/empathy with alsa, instead of pulseaudio. It should be possible to use alsa instead.
Pulseaudio is a hard requirement of empathy, and it provides important features to empathy audio conversations that pure ALSA can not do (unless one re-implements what PA does just because... reasons...). It might be possible to run empathy without audio working with pulseaudio daemon disabled, but its libraries are used and so PA is a hard requirement we can not make optional without huge amount of work, and frankly, don't see a reason to. "It should be possible to use alsa instead." - You already use ALSA via pulseaudio on Linux systems, just in more advanced ways that the alsa-lib APIs do not directly make easy to do, which is exactly what PA provides (easy usage of advanced features on top of ALSA with very low effort needed from the application developer, as PA takes care of the complexities with ALSA).
(In reply to Mart Raudsepp from comment #1) > Pulseaudio is a hard requirement of empathy, and it provides important > features to empathy audio conversations that pure ALSA can not do (unless > one re-implements what PA does just because... reasons...). Thanks for your reply. Interesting, can you give me examples of features that empathy requires that pulseaudio provides but alsa doesn't ?
Echo cancellation; Suppressing background sounds on incoming call; Stream volumes, volume state and dB saving of that stream; Seamlessly switching used microphone and/or speakers/headset without any drop of audio chat connection with the other party; Seamless support of bluetooth headsets (e.g those small ones that go into one ear and have a microphone too), commonly used in voice chat cases; Audio code that doesn't have to be a wall of text - including automatically doing lower latency when possible; not having to maintain own software volume control logic. PA started to be hard required during empathy development in July 2011 and going forward.
FTR, we tried to make pulseaudio optional for as long as possible back when it was first introduced in Gnome 2 in multiple Gnome components. Some Gnome upstreams were hostile to patches making it optional and it eventually came to a point were it would require inadequate amount of work on our side to maintain such patches. This is still going on today for some of the patches we carry to make things such a networkmanager or bluetooth or cups optional, so even if PA does provide interesting things and maybe you are not interested in them, please consider that the option simply isn't always possible to maintain.
