Add PortAudio libraries with ALSA support for Linux/Raspberry Pi

[CrystalMare]

I've tried using the FFT example sketch to visualize the monitor output of my computer's sound card. But I've noticed that there is a 2~ second delay between the audio output, and the visualization on the screen.

Any ideas what could be causing this?

I'm using Processing 3.3.7 and version 2.0.1 of processing-sound Using GNU/Linux with ALSA&PulseAudio.

If you need any specific details, please tell me. I can't think of anything else to add.

public class AudioVisualizer extends PApplet {

    private FFT fft;
    private AudioIn in;
    private int bands = 16;
    private float[] spectrum = new float[bands];

    public static void main(String[] args) {
        PApplet.main(AudioVisualizer.class.getCanonicalName());
    }

    @Override
    public void settings() {
        size(512, 360);
    }

    @Override
    public void setup() {
        background(255);

        // Create an Input stream which is routed into the Amplitude analyzer
        fft = new FFT(this, bands);
        in = new AudioIn(this);
        // start the Audio Input
        in.start();
        in.play();

        // patch the AudioIn
        fft.input(in);
    }

    @Override
    public void draw() {
        background(255);
        fft.analyze(spectrum);

        for(int i = 0; i < bands; i++){
            // The result of the FFT is normalized
            // draw the line for frequency band i scaling it up by 5 to get more amplitude.
            line( i, height, i, height - spectrum[i]*height*5 );
        }
    }
}

[rvorias]

Also having this problem. Processing 3.5.3 Elementary OS Juno (Ubuntu 18.04 LTS) Checked code on windows and code is ok.

[JJ-Atkinson]

Was a solution found? Still see it.

Ubuntu 18.04 lts

[JJ-Atkinson]

I found a hack around this by using my headphone out connected directly to my mic in. Zero latency now.

[kevinstadler]

Adding the option of using PortAudio with ALSA support (in line with c64e56c) would probably greatly enhance latency/performance on Linux, see e.g. https://github.com/PortAudio/portaudio/wiki/Platforms_RaspberryPi