I know this isn’t really news to anyone, but PulseAudio definitely sucks. What sucks even more are desktop applications that won’t let me bypass Pulse and use ALSA directly. Like Skype.
I’ve been having a huge problem lately. For the last couple of weeks I couldn’t get Skype to work with my USB microphone on my main desktop at home. Originally I suspected it was a problem with how Skype interacted with PulseAudio. My deepest fear was that it might also be a problem with the latest Linux kernel, 3.19, that just showed up in Fedora 21.
Desperate, I put out feelers on the Fedora and Skype fora, to no avail.
As a last resort I installed and tested Skype on my company workstation in the office, because the software configuration was nearly identical to what I’m running at home.
It worked. Well, at least with the old Logitech USB headset. To get to that point, however, I had to go in and disable all other audio inputs. Not mute them, mind you. Disable. What I learned from that was that while other native Linux apps were able to deal with multiple, albeit idle, audio inputs, Skype would only work if only one was enabled.
At home I found that I was also able to get things working by following the same approach.
In PulseAudio Volume Control (pavucontrol), I went to the Configuration tab and found 3 audio interfaces: my QuickCam Communicate webcam mic, the system Built-in Audio (set to Analog Stereo Duplex), and my USB dynamic mic.
I set the QuickCam to Off and the Built-in Audio to Analog Stereo Output. The USB mic I left set to Analog Stereo Output.
These new settings left Skype with just a single output and a single input to work with, allowing it to do its simple-minded thing.
Here are the actual screens from PA Volume Control as they appear on my system:
On the Configuration tab the QuickCam’s audio interface is completely disabled, while the Built-in Audio has been switched to Output only, leaving the Q1U mic as the sole audio input (note that I did change the Profile to Analog Mono Input, although it would work just as well with Analog Stereo Input).
Given the above configuration changes, the Q1U is the only device that shows up on the Input tab. No further changes are required there.
Likewise, the Output tab only shows a single device: the Built-in Analog Stereo’s Line Out (my earbuds connect to Line Out rather than a headphone jack for purely reasons of cable length).