Question

In windows media player, do you know that music visualization graph that changes based on frequency and pitch? What I want is to implement this into an iphone game.

I’ll try to explain this as well as I can. I will be playing classical music in a game. I want to use the music’s volume/pitch/whatever it is called, to affect gameplay. Like, if suddenly in the music, the volume raises (not the volume of the iphone, but the actual playing of the music) it would increase the chances of a spawn or something.

I’m not asking for a guide on how to implement this, I want to know if there is something that can give me numbers or something based on the pitch/volume/high and low notes of the song that was playing in a game.

Oh and if anyone can tell me what the name of the music graph I am looking for, it would be greatly appreciated.

Answer 1

This sample shows how to do what you want to do. The visualizer in WMP uses the amplitude (volume) of the signal as well as frequency information (using Fast Fourier Transform – probably) to construct the visualization effect.

You can also use the simpler AVAudioPlayer API, if you’re interested in just responding to the music’s current volume level (and if you want to skip the frequency analysis part). The API includes a callback that notifies your app periodically of the current audio volume.