macos - How to programmatically list processes currently using the default sound output on Mac OS 10.6

itemprop="text">

I would like to know if there is a
programmatic way (public API, terminal command, AppleScript, etc.) to list all processes
currently playing sound through the default sound output in Mac OS 10.6
?

I already tried using the "lsof |
grep -i coreaudio" terminal command to list processes having a handle on Core Audio, but
this does not tell me if those processes are outputting sound currently; they might have
outputted sound before or they intend to do it in the
future.

For instance, if I open Google Chrome,
at first it is not listed when I use the lsof command. Then, if I load a video on
Youtube, it connects to Core Audio, so it gets listed. But, when I'm done with the
video, even if I close the browser window completely, it still is listed as being
connected to the driver even though it is obviously not playing sound anymore. It only
stops being listed when I quit the process.

Note
that while having a lengthy programming experience in C++ on Windows platforms and
knowing the Windows API pretty well, I'm rather new to Mac OS programming, so please be
understanding if I miss something
obvious.

Thanks,
François
Charron

Answer

I know this post is pretty old, but it does
have some votes so people might run into it via search
queries.

I am pretty sure that this
is not possible unless you write a CoreAudio plug-in that gets embedded in each process
that uses CoreAudio. The work is very similar to creating a Mac version of the Windows
Volume Mixer.

There is an open source
implementation of this ( rel="nofollow">https://github.com/zonque/PulseAudioOSX) although it is
unmaintained and I haven't had great luck in getting it to build. There are also
proprietary solutions such as Prosoft Engineering's Hear that should be able to do this
but I don't think they provide an API to
query.

Note: I have built MuteTab which tries to
do the same within a browser (prior to changes in Flash and the introduction of audio
indicators) and have built mute.fm (Windows) which would need this as well as an ability
to control the volumes if I ported it to work on OSX.