Interpreting analog sound signals from line-in

[Arokh]

Hi,

I have an old amplifier which connects to a tuner and a tapeplayer,

which are connected though three chinch cables (2xaudio 1xcommunication).

 

Now instead of connecting the com-cable to the tapeplayer,

I connected it to a loudspeaker and it was as I have hoped:

As soon as I pressed a button on the amp remote,

I could hear a signal coming from the loudspeaker.

 

Now the next step of the plan is to connect it to my soundcards line-in port,

and then interpret the signal.

 

The problem:

I have next to no knowledge about audio processing.

I guess I'd have to extract the frequency and the volume level,

so I can differenciate between the different buttons pressed or holded.

 

Can anyone point me into the right direction where to start,

so I can accomplish this?

 

If you want I can attach a sound sample of different signals.

 

I tried some different source code samples, but I've yet to find one that works:

http://www.codeproject.com/KB/audio-video/cswavrec.aspx

In this one I always get a nullpointer exception.

I already tried the suggestions in the comments but to no avail.

Edited April 30, 2009 by Arokh