Q I like to use Skype to talk while playing online games. I've just switched over to Ubuntu 8.10 from Windows, but I've found I'm unable to use sound in more than one application at once. Furthermore, after one Skype call ends, I need to play a random sound, to 'reset' the sound device, otherwise I'm told there's an audio playback error. The worst thing is that if I'm playing games and someone calls me, I can't answer their call because of this, so I have to exit the game or start a call before playing. My webcam also won't work with Skype, yet it will with Ekiga.
A Did you install Skype from a file downloaded from skype.com or via the Synaptic package manager? If it's the former, you should uninstall this and use Synaptic. Skype is not included in the standard Ubuntu repositories, so you'll need to add the Medibuntu repository before you can install software from it. This means you'll get versions tested for Ubuntu, be notified of updates and gain access to other useful software in the repository. Add Medibuntu by typing
sudo wget http://www.medibuntu.org/sources.list.d/intrepid.list --output-document=/etc/apt/sources.list.d/medibuntu.list
into a terminal while Synaptic isn't running. You can also find this command at https://help.ubuntu.com/community/Medibuntu, so you can paste it into the terminal to avoid typing errors. Then run Synaptic, click on Reload to get the latest list ofpackages and search for Skype. You also need to make sure you have the correct devices selected for Skype. As your webcam works with Ekiga, check that you have the same device selected in Skype. This is usually /dev/video0, unless you have a TV card fitted, in which case that will be video0 and your webcam is video1.
I've also noticed that Skype only picks up devices that are connected when it starts, so ensure you plug in the camera before running Skype. Your sound problem sounds like (sorry) Skype is trying to use OSS, the older sound system for Linux, and not ALSA (Advanced Linux Sound Architecture). ALSA provides software mixing, so that more than one program can use the sound device at the same time, whereas OSS locks up the device for its own use, preventing any other program from using it. Skype gives an array of choices for audio devices, and the default option is often not the best one.
If you try the other devices in turn, this problem will almost certainly go away. You may find a similar solution applies with the other programs as well, depending on whether they allow you to choose the sound device. If not, installing the alsa-oss package should enable any OSS programs to be run through ALSA.