Blog - Sound equalizer with FMod and OpenGL

Some time ago, just for fun, a wrote a simple sound equalizer. Example of how it works can be found on YouTube

Learn more and download free source...
Application uses fmod sound library to play sound and to get sound info from mp3 files. Visualization was made with use of OpenGL and GLUT library. It was compiled and testes on both Linux and Windows operated computers. Application also uses libpng to save rendered frames.
Most important part of code is fmod initialization

void initFMOD(char * path)
{
 System_Create(&fmodsys);
 fmodsys->init(1,FMOD_INIT_NORMAL,0);
 cout << "\nfile: " << path << endl;
 fmodsys->createSound(path,
			FMOD_SOFTWARE | FMOD_2D | FMOD_CREATESTREAM,
			0, &fmodsnd);
 fmodsys->playSound(FMOD_CHANNEL_FREE,fmodsnd,true,&fmodchn);
 specL = (float*)malloc(SPECLEN*sizeof(float));
 specR = (float*)malloc(SPECLEN*sizeof(float));
 //tmp
 unsigned int len;
 fmodchn->setVolume(1);
 fmodsnd->getLength( &len, FMOD_TIMEUNIT_MS );
 fmodchn->setPosition( (int)(len*0.0), FMOD_TIMEUNIT_MS );
};

Variables specL and specR will be used to store FFT sound spectrum. We get FFT spectrum we need to use fmod Channel object method

fmodchn->getSpectrum( specL, SPECLEN, 0, FMOD_DSP_FFT_WINDOW_BLACKMAN ); 
fmodchn->getSpectrum( specR, SPECLEN, 1, FMOD_DSP_FFT_WINDOW_BLACKMAN );

And... thats all You need to create simple sound equalizer :)

Some people asked for code, and now it can be downloaded here. My code can be quite easily customized, spheres behavior can be tuned with two functions.

double spherePeek( double value)
 
double sphereScaler( double value )

First one controls how high peeks go out of the sphere. Second one controls sphere scaling.
Next some customization can be made where call to sphere rendering function is made.

void uglSphere( GLdouble radius, 
GLint slices, GLint stacks, 
GLboolean half = 0,  
GLdouble tang = PI, GLdouble pang = 2*PI)

Seting different parameters of this function one can get sphere ( tang=PI, pang=2*PI ) or ring (tang=PI/2, pang=2*PI) and so on. For example in next video we can see 'rings' instead of spheres.
Forgive the music, i needed more bass :)


almost forgot