Over at Audio Cookbook, John Keston has been running a few experiments with using image filters in Photoshop to process sound. Running the audio data through a Gaussian blur or Spherize filter, he was able to create some incredibly diverse effects from a simple electric piano input.
To test this concept I created a simple pattern with an electric piano patch and opened it in Photosounder. Without changing any settings I immediately saved the sound as a bitmap image. Next I opened the image in Photoshop and started experimenting with filters. Once I had some filtered images I loaded them back into Photosounder to see how they sounded. Gaussian blur and Liquefy created some unique effects, but my favorite of the bunch was Glowing Edges. This filter seems to transform the electric piano into a haunting choral passage.
John has a number of MP3 samples on his site. To get the audio in and out of Photoshop, he's using a tool called Photosounder which translates a waveform into bitmap data and vice-versa. I've never used the app, but from looking at the output images, time is represented on the x dimension, y represents the frequency, and the brightness of the pixel is determined by the amplitude at that frequency/time coordinate.
Anyone interested in writing a sound to image converter in Perl?