How to calculate sound frequency in android?

Question

I want to develop app to calculate Sound frequency in Android. Android Device will take Sound from microphone (i.e. out side sound) and I have one color background screen in app. on sound frequency changes i have to change background color of screen .

So my question is "How can i get sound frequency"?

is there any android API available?

Please help me out of this problem.

Answer 1

Your problem was solved here EDIT: archived here. Also you can analyze the frequency by using FFT.

EDIT: FFTBasedSpectrumAnalyzer (example code, the link from the comment)

Answer 2

Thanks for Reply I have done this by using sample on
http://som-itsolutions.blogspot.in/2012/01/fft-based-simple-spectrum-analyzer.html

Just modify your code for to calculate sound frequency by using below method

 // sampleRate = 44100 

public static int calculate(int sampleRate, short [] audioData){

    int numSamples = audioData.length;
    int numCrossing = 0;
    for (int p = 0; p < numSamples-1; p++)
    {
        if ((audioData[p] > 0 && audioData[p + 1] <= 0) || 
            (audioData[p] < 0 && audioData[p + 1] >= 0))
        {
            numCrossing++;
        }
    }

    float numSecondsRecorded = (float)numSamples/(float)sampleRate;
    float numCycles = numCrossing/2;
    float frequency = numCycles/numSecondsRecorded;

    return (int)frequency;
}