How to detect which program is playing sound on windows 7?

Question

I'm trying to write a little background program that stops music playing Winamp when another program plays sounds. The part about the accessing Winamp through Java is already solved now I need a way to detect which program plays the currently played sound (probably I want to allow some programs to play their sound without stopping my music). Although I'm doing this in Java (+ the winapi) everything in any language would help.

[edit] as I just got the first downvote on my first question here is some more detail: I already figured out how to use the winapi (but I don't know it) and capture things like volume levels and stuff. What still makes trouble is the mentioned detection of the origin of a sound that is played and aslo which program plays sounds. Is there anything in the winapi that could help me to do this?[/edit]

Answer 1

As Deanna mentioned, you can enumerate audio playback sessions just like Volume Mixer application (started from system tray icon) does and obtain per-session meters indicating session status.

You can find a C++ application that does it in this answer: Peak meters for individual programs on Windows 7. The meters are per-session and an audio-enabled application might have one or more sessions in it, but eventually as long as you enumerate them, you can figure out if there is any active playback there.

Answer 2

I believe the Windows Core Audio API in Vista+ allows you to get the VU levels for each application (After all, the mixer shows it). This should allow you to turn down one application when another is playing, etc.