Real-Time Music Visualization on the iPhone GPU (opens in new tab)

I wrote a very similar prototype a while ago. Here's a video - https://www.youtube.com/watch?v=oYZEDSzX7MU&feature=youtu.be

I didn't realise at the time, but the X axis is not in logarithmic scale, so most of the audible frequencies are bunched on the left hand side.

you're right, thank you for the feedback, we'll try to add video samples with royalty free audio content.

Hey, I'm Adrian. I did the 'More colors' shader.

Given the nature of the project, a hackathon, sticking to the last computed FFTs and a notion of time was all we need to play with nice shader effects.

I'm currently playing with tensorflow on my spare time. I'd like to use a neural net to find interesting features of a track and inputting this to a shader. That's what I would do if I had another go at it.

Yeah - we need a Geiss port :) http://www.geisswerks.com/geiss/

There is definitely an impact on the battery. The FFT part is well optimised (thanks to the Accelerate framework). What is costly is mainly the shader... and it really depends on the shader. A very simple shader is usually less than 5% of the GPU usage (according the Xcode Instruments, and on a recent iPhone). However if you do a lot in your shader it's going to be much more costly.