Adaptation of ShaderToy's AudioSurf shader for Cinder. Actual audio data is replaced with random noise to keep it simple. I kept the original shader code without making any changes. Note that ```iResolution``` must be passed as a Vec3f.

audio_surf_frag.glsl

// by nikos papadopoulos, 4rknova / 2013
// Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

uniform vec3		iResolution;           // viewport resolution (in pixels)
uniform float		iGlobalTime;           // shader playback time (in seconds)
//uniform float		iChannelTime[4];       // channel playback time (in seconds)
//uniform vec3		iChannelResolution[4]; // channel resolution (in pixels)
//uniform vec4		iMouse;                // mouse pixel coords. xy: current (if MLB down), zw: click
uniform sampler2D	iChannel0;          // input channel. XX = 2D/Cube
//uniform vec4		iDate;                 // (year, month, day, time in seconds)

#ifdef GL_ES
precision highp float;
#endif

#define PI  3.14159
#define EPS .001

#define T .03  // Thickness
#define W 2.   // Width
#define A .09  // Amplitude
#define V 1.   // Velocity

void main(void)
{
	vec2 c = gl_FragCoord.xy / iResolution.xy;
	vec4 s = texture2D(iChannel0, c * .5);
	c = vec2(0., A*s.y*sin((c.x*W+iGlobalTime*V)* 2.5)) + (c*2.-1.);
	float g = max(abs(s.y/(pow(c.y, 2.1*sin(s.x*PI))))*T,
				  abs(.1/(c.y+EPS)));
	gl_FragColor = vec4(g*g*s.y*.6, g*s.w*.44, g*g*.7, 1.);
}

audio_surf_vert.glsl

void main()
{
	gl_TexCoord[0] = gl_MultiTexCoord0;
	gl_Position = ftransform();
}

AudioShaderApp.cpp

#include "cinder/app/AppNative.h"
#include "cinder/gl/gl.h"
#include "cinder/gl/GlslProg.h"
#include "cinder/gl/Texture.h"
#include "cinder/Rand.h"

using namespace ci;
using namespace ci::app;
using namespace std;

class AudioShaderApp : public AppNative {
public:
	void setup();
	void update();
	void draw();	

private:
	gl::GlslProg	mShader;
	gl::Texture		mTexture;
};

void AudioShaderApp::setup()
{
	// load and compile shader
	try {
		mShader = gl::GlslProg( loadAsset("audio_surf_vert.glsl"), loadAsset("audio_surf_frag.glsl") );
	}
	catch( const std::exception& e )
	{
		console() << e.what() << std::endl;
	}
}

void AudioShaderApp::update()
{
	// create a random FFT signal for test purposes
	unsigned char signal[1024];
	for(int i=0;i<512;++i)
		signal[i] = (unsigned char) (Rand::randUint() & 0xFF);
	
	// add an audio signal for test purposes
	for(int i=0;i<512;++i)
		signal[512+i] = (unsigned char) (Rand::randUint() & 0xFF);

	// store it as a 512x2 texture
	mTexture = gl::Texture( signal, GL_LUMINANCE, 512, 2 );
}

void AudioShaderApp::draw()
{
	gl::clear(); 

	// bind texture to slot 0
	mTexture.enableAndBind();

	// bind shader and set uniforms
	mShader.bind();
	mShader.uniform( "iResolution", Vec3f( getWindowWidth(), getWindowHeight(), 0.0f ) );
	mShader.uniform( "iGlobalTime", float( getElapsedSeconds() ) );
	mShader.uniform( "iChannel0", 0 );

	// run full screen pass
	gl::drawSolidRect( getWindowBounds() );

	// unbind shader and texture
	mShader.unbind();
	mTexture.unbind();
}

CINDER_APP_NATIVE( AudioShaderApp, RendererGl )