KDE and sound device "lock-out"

[ShakyJake]

Hope the subject line makes sense.

The problem I'm having is apparently KDE is using the sound device for a moment and not allowing another program to play sound.

For example, I boot up, launch KDE. if I were to immediately start Mplayer to play a video or XMMS to play a MP3, it will say the sound device is in use -- although no sound is actually playing. If I wait for about 1-2 minutes the apps run fine.

Honestly, to me, it seems like there is no sound mixing going on. I know if a movie is playing and someone IM's me, I won't hear the IM sound until after i shut down the movie. So I suspect it's partly the fact that no sound mixing is being allowed.

Any ideas? Thanks in advance.

[furanku]

Hopfully this will be history soon... but for so long: KDE has its own audio mixer called arts. arts does it's output to an underlaying driver. I guess in your case dirctly to alsa, Linux' harware sound driver, but arts can also send it's output to some other audio systems, which send thier output to alsa finally.

If arts uses alsa directly and your soundcard doesn't support hardware mixing or isn't configured to do software mixing (see below) arts blocks the sound device for all non-KDE applications. As this is not a satifiying solution you can change this behavior un the KDE control center unter "Sound & Multimedia -> Sound System". In the tab "Hardware" you can configure the driver arts uses. In the tab "General" you can set the time arts after that arts releases the sound device with the slider "Auto-Suspend".

So if you can not play several sounds at the same time, you have several possibilties.

Alsa by itself supports mixing in two ways. If your soundcard can do it in hardware, and the alsa driver supports it, you're out of trouble. That seems not to be the case for you. The alsa drivers also can do software mixing. Search the forum for "dmix" (or take a look at the alsa homepage) for further information.

arts can also send it's output to jack, which is a low-latency audio system and can also do the mixing. You must emerge the jack-audio-connection-kit first and set it up, probably the most comfortable way is to use the qt-based graphical fronten qjackctl.

In every case KDE applications should use arts, and should not cause any problems in any configuration.
But non KDE applications have to be configured to use the right driver. mplayer for example shows you which audio output it supports if you type