How can I display a simple animated spectrogram to visualize audio from a MixerHostAudio object?

Question

Hi all, I'm working off of some of Apple's sample code for mixing audio (http://developer.apple.com/library/ios/#samplecode/MixerHost/Introduction/Intro.html) and I'd like to display an animated spectrogram (think itunes spectrogram in the top center that replaces the song title with moving bars). It would need to somehow get data from the audio stream live since the user will be mixing several loops together. I can't seem to find any tutorials online about anything to do with this.

Thanks!

Jack

Answer 1

Apple's aurioTouch example app (on developer.apple.com) has source code for drawing an animated frequency spectrum plot from recorded audio input. You could probably group FFT bins into frequency ranges for a coarser bar graph plot.