Saving FFT Spectrum in Fmod Studio C++ - c++

Question

I'm trying to save the Spectrum in my FMOD_DSP_PARAMETER_FFT but I'm only receiving the spectrum full of zeros, if you can watch my mistake I will agree, I think that I'm not connecting well the DSP to the channel or something similar because I don't find the error in the code.
My code now is like this:
FMOD::System *system;
FMOD::Sound *sound1;
FMOD::Channel *channel = 0;
FMOD::ChannelGroup *mastergroup;
FMOD::ChannelControl *control;
FMOD::DSP *mydsp, *dsphead, *dspchannelmixer;
FMOD::DSPConnection *conection;
FMOD_RESULT result;
unsigned int version;
result = FMOD::System_Create(&system);
result = system->getVersion(&version);
result = system->init(32, FMOD_INIT_NORMAL, NULL);
result = system->createSound("MySong.mp3",FMOD_DEFAULT, 0, &sound1);
result = sound1->setMode(FMOD_LOOP_NORMAL);
result = system->playSound(sound1, 0, true, &channel);
/*
Create the DSP effect.
*/
result = system->getMasterChannelGroup(&mastergroup);
result = system->createDSPByType(FMOD_DSP_TYPE_FFT, &mydsp);
result = system->getMasterChannelGroup(&mastergroup);
result = mastergroup->addDSP(0, mydsp);
result = mydsp->setBypass(true);
result = mydsp->setActive(true);
char s[256];
unsigned int len;
float freq[32];
float fft = 0;
std::vector<float> fftheights;
float m_spectrum_data[FFT_NUM_BINS];
while (1) { //program loop
unsigned int ms = 0;
unsigned int lenms = 0;
bool playing = 0;
bool paused = 0;
int channelsplaying = 0;
if (channel)
{
FMOD::Sound *currentsound = 0;
result = channel->setPaused(false);
result = channel->setMute(false);
result = channel->isPlaying(&playing);
result = channel->getPaused(&paused);
result = channel->setVolume(0.5);
result = channel->getPosition(&ms, FMOD_TIMEUNIT_MS);
channel->getCurrentSound(&currentsound);
if (currentsound)
{
result = currentsound->getLength(&lenms, FMOD_TIMEUNIT_MS);
}
}
system->getChannelsPlaying(&channelsplaying);
FMOD_DSP_PARAMETER_FFT *fftparameter;
float val;
char s[256];
unsigned int len;
float *data = 0;
float freq[32];
int rate, chan, nyquist;
int windowsize = 1024;
result = system->getSoftwareFormat(&rate, 0, 0);
result = mydsp->setParameterInt(FMOD_DSP_FFT_WINDOWTYPE, FMOD_DSP_FFT_WINDOW_TRIANGLE);
result = mydsp->setParameterInt(FMOD_DSP_FFT_WINDOWSIZE, windowsize);
result = mydsp->getParameterFloat(FMOD_DSP_FFT_DOMINANT_FREQ, &val, 0, 0);
result = mydsp->getParameterData(FMOD_DSP_FFT_SPECTRUMDATA, (void **)&fftparameter, &len, s, 256);
nyquist = windowsize / 2;
for (chan = 0; chan < 2; chan++)
{
float average = 0.0f;
float power = 0.0f;
for (int i = 0; i < nyquist - 1; ++i)
{
float hz = i * (rate * 0.5f) / (nyquist - 1);
int index = i + (16384 * chan);
if (fftparameter->spectrum[chan][i] > 0.0001f) // arbitrary cutoff to filter out noise
{
average += data[index] * hz;
power += data[index];
}
}
if (power > 0.001f)
{
freq[chan] = average / power;
}
else
{
freq[chan] = 0;
}
}
printf("\ndom freq = %d : %.02f %.02f\n", (int)val, freq[0], freq[1]);
}
My fftparameter->spectrum is always an array of zero values...
Is posible to connect it without modify the sound that is playing??
Thank you.

Answer 1

There are a few standout issues in your code example.
The FFT DSP has been bypassed with result = mydsp->setBypass(true); causing it to not process.
There are no calls to System::update in the main loop.
The main loop has no sleep so it will spin as fast as possible.
I think your main issue is probably the setBypass call, use setBypass(false).