On Tue, 29 Jun 2010, David DEMELIER wrote:
When you are running an application that sits on a audio device, every other application that needs it will fails opening it and they will say "device busy". I heard that we need to have a sound server running to be able to do this : having many applications running on the same sound card.
You can do this in userland with a sound server such as pulseaudio, but a) it's a point of failure and b) client software needs to be compiled to use it.
Better yet is an in-kernel audio mixer which gives a different audio device that allows multiple opens and can mix the streams. Then you simply need to point your software at the alternative mixer device (probably via a symlink in /dev). See the proposed project here:
http://www.netbsd.org/contrib/soc-projects.html#kernel-audio-mixer -- Stephen