Getting Audiosource info and data in Unity

Category : Full Script , Game Development , Javascript , Unity

Earlier today I stumbled upon a perfect little script for extracting audio data from an audiosource component in unity. It does all the calculation for getting the RMS value, the decibels, and frequency.

This script can easily be applied to make things behave to the music being played in the Audiosource component. Like making an object bounce or move back and forth with the music.

Thanks to Aldonaletto from this Unity Answers post for making this one and explaining it so well. Script below.

var qSamples: int = 1024; // array size
var refValue: float = 0.1; // RMS value for 0 dB
var threshold = 0.02; // minimum amplitude to extract pitch

var rmsValue: float; // sound level - RMS
var dbValue: float; // sound level - dB
var pitchValue: float; // sound pitch - Hz

private var samples: float[]; // audio samples
private var spectrum: float[]; // audio spectrum
private var fSample: float;

function Start () {
    samples = new float[qSamples];
    spectrum = new float[qSamples];
    fSample = AudioSettings.outputSampleRate;
}

function AnalyzeSound(){
    audio.GetOutputData(samples, 0); // fill array with samples
    var i: int;
    var sum: float = 0;
    for (i=0; i < qSamples; i++){
        sum += samples[i]*samples[i]; // sum squared samples
    }

    rmsValue = Mathf.Sqrt(sum/qSamples); // rms = square root of average
    dbValue = 20*Mathf.Log10(rmsValue/refValue); // calculate dB

    if (dbValue < -160) dbValue = -160; // clamp it to -160dB min

    // get sound spectrum
    audio.GetSpectrumData(spectrum, 0, FFTWindow.BlackmanHarris);

    var maxV: float = 0;
    var maxN: int = 0;

    for (i=0; i < qSamples; i++){ // find max

        if (spectrum[i] > maxV && spectrum[i] > threshold){
            maxV = spectrum[i];
            maxN = i; // maxN is the index of max
        }

    }

    var freqN: float = maxN; // pass the index to a float variable

    if (maxN > 0 && maxN < qSamples-1){ // interpolate index using neighbours
        var dL = spectrum[maxN-1]/spectrum[maxN];
        var dR = spectrum[maxN+1]/spectrum[maxN];
        freqN += 0.5*(dR*dR - dL*dL);
    }

    pitchValue = freqN*(fSample/2)/qSamples; // convert index to frequency

}

var display: GUIText; // drag a GUIText here to show results

function Update () {
    if (Input.GetKeyDown("p")){
        audio.Play();
    }

    AnalyzeSound();

    if (display){

        display.text = "RMS: "+rmsValue.ToString("F2")+" ("+dbValue.ToString("F1")+" dB)\n"+"Pitch: "+pitchValue.ToString("F0")+" Hz";

    }

}

var qSamples: int = 1024; // array size

var refValue: float = 0.1; // RMS value for 0 dB

var threshold = 0.02; // minimum amplitude to extract pitch

var rmsValue: float; // sound level - RMS

var dbValue: float; // sound level - dB

var pitchValue: float; // sound pitch - Hz

private var samples: float[]; // audio samples

private var spectrum: float[]; // audio spectrum

private var fSample: float;

function Start () {

samples = new float[qSamples];

spectrum = new float[qSamples];

fSample = AudioSettings.outputSampleRate;

}

function AnalyzeSound(){

audio.GetOutputData(samples, 0); // fill array with samples

var i: int;

var sum: float = 0;

for (i=0; i < qSamples; i++){

sum += samples[i]*samples[i]; // sum squared samples

}

rmsValue = Mathf.Sqrt(sum/qSamples); // rms = square root of average

dbValue = 20*Mathf.Log10(rmsValue/refValue); // calculate dB

if (dbValue < -160) dbValue = -160; // clamp it to -160dB min

// get sound spectrum

audio.GetSpectrumData(spectrum, 0, FFTWindow.BlackmanHarris);

var maxV: float = 0;

var maxN: int = 0;

for (i=0; i < qSamples; i++){ // find max

if (spectrum[i] > maxV && spectrum[i] > threshold){

maxV = spectrum[i];

maxN = i; // maxN is the index of max

}

var freqN: float = maxN; // pass the index to a float variable

if (maxN > 0 && maxN < qSamples-1){ // interpolate index using neighbours

var dL = spectrum[maxN-1]/spectrum[maxN];

var dR = spectrum[maxN+1]/spectrum[maxN];

freqN += 0.5*(dR*dR - dL*dL);

}

pitchValue = freqN*(fSample/2)/qSamples; // convert index to frequency

}

var display: GUIText; // drag a GUIText here to show results

function Update () {

if (Input.GetKeyDown("p")){

audio.Play();

}

AnalyzeSound();

if (display){

display.text = "RMS: "+rmsValue.ToString("F2")+" ("+dbValue.ToString("F1")+" dB)\n"+"Pitch: "+pitchValue.ToString("F0")+" Hz";

}

A greater explanation is at the source.

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Justin Fletcher

Game Designer, Programmer, Lover of all things retro. I've been a programmer for about 8 years. Got into game development part time 6 years ago and haven't been able to put it down.

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Getting Audiosource info and data in Unity