There are definitely some tools like that out there. If you search for spectrum analyzers you should be able to find something. I think there might even be one as a visualizer for itunes. Audacity, an free audio editor has a spectrum view as well.

Most of these applications will display a grid which represents time in one direction and frequency in the other. The pixels will be colored based on the volume of that frequency at each time.

Unfortunately I don’t think this sort of visualization will be as easy to understand as you would hope. A single note from an instrument will not be seen as a blip and the base frequency but a more complex structure of overtones. If you’re only looking at one instrument at a time, it might be possible, depending on the instrument, but it would be easy.

I’m a composer, and sometimes I work on transcribing performances. I’ve started using a method of scoring to a video of a performance. I can get a really accurate transcription by watching performer’s fingers. Problem is, I need a video of the performers.

I have an idea though: if I could take a sound file and turn it into a video file, the visual part being a waveform visualization (a clear and basic one) I could make very accurate transcriptions from a sound file.

input: sound file (wav or aiff)
output: video file (mpeg or mp2 or whatever) with original sound file as audio component and waveform visualization as visual component.

Does a tool like that exist, or would it be an easy extension of what you have here?

For others having a problem with this example:
for the ESS library – make sure you restart processing after you extracted
for the audio input in windows – turn on/unmute stereo mix as input, in volume settings.

If your still not getting anything you can try scaling up the signal within processing by increasing the fourth parameter of the renderSpectrum function (currently 400) within the draw loop. Other than than that it might help to yell at your computer.