Author Topic: listen to audio output / audio input  (Read 8361 times)


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listen to audio output / audio input
« on: July 14, 2009, 10:06:14 »
Hello Community,

I am quiet new to c/c++ and worked earlier with webased coding languages like php together with js and have some experiences in Delphi (which made actually me start my new project in c++).

At the moment I am working on a "realtime" ;) sound to light controller software. I decided to use the Vamp plugin to analyse the incomming audio signal. My Problem is that i dont have any expeririences with FFT, is there any possibility to use the build in one from the vamp plugin to listen to the Microphone / Audiocallback source?

By the way, the next problem is that it needs to run under windows, because of the people who are (hopefully) going to use the software and I am working with QT4.


p.s. this is no commercial project


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Re: listen to audio output / audio input
« Reply #1 on: July 16, 2009, 09:58:12 »
Hi, I've just recently started using vamp but I think for your purpose it should work.
Afaik vamp has no support for audio interfaces. My guess is, your host needs to read from the operating system's audio interface and then feed it to the vamp plugins. Maybe QT offers a wrapper for that os-audiointerfaces. Note that vamp itself doesn't require qt, you can use any toolkit you like.

As you are using windows, I recommend building the host-sdk binaries yourself.



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Re: listen to audio output / audio input
« Reply #2 on: July 16, 2009, 15:44:45 »

Your host can use the PluginInputDomainAdapter to avoid having to perform FFTs itself.  If you load plugins using a PluginLoader with the ADAPT_ALL_SAFE or ADAPT_ALL flag set, the PluginLoader will wrap your plugin in a PluginInputDomainAdapter for you and you will be able to safely send time-domain data to every plugin.

See the online API docs at for more about these loaders and adapters.

The Vamp SDK builds fine under Windows; if you're using Visual Studio, there are project files included in the build/ directory.  For MinGW you'll have to run the gauntlet of "configure" and adjust the results to suit.

You should probably also read this thread:,34.0.html