Android Visualizer implementation crash

Question

I am trying to implement the Android Visualizer class. I have looked up other trouble threads but I am still getting a fatal error. This all looks to me like it should work correctly, for whatever reason the AVD keeps on crashing.

First off, I am using the permissions:

<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS"/>

Here is my logcat:

12-21 15:10:46.983: D/dalvikvm(642): Not late-enabling CheckJNI (already on)
12-21 15:10:48.823: D/MediaPlayer(642): Couldn't open file on client side, trying server     side  
12-21 15:10:53.603: E/AudioEffect(642): set(): AudioFlinger could not create effect,    status: -22
12-21 15:10:53.603: E/visualizers-JNI(642): Visualizer initCheck failed -4
12-21 15:10:53.613: E/Visualizer-JAVA(642): Error code -4 when initializing Visualizer.
12-21 15:10:53.613: E/Visual Ex(642): Cannot initialize Visualizer engine, error: -4
12-21 15:10:53.964: D/gralloc_goldfish(642): Emulator without GPU emulation detected.

And my code:

package MediaPlayer.namespace;

import java.io.IOException;

import android.app.Activity;
import android.media.MediaPlayer;
import android.media.MediaRecorder;
import android.media.audiofx.Visualizer;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;

public class MediaPlayerActivity extends Activity 
{
Visualizer      visual;
int             formattedVizData[];
byte            rawWaveForm[];
int             cont = 0xFF;

public void onCreate(Bundle savedInstanceState) 
{
    //start
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);


    ///start media player & visualizer.
    MediaPlayer mediaPlayer = new MediaPlayer();
    mediaPlayer = MediaPlayer.create(this, Uri.parse("http://vprbbc.streamguys.net:80/vprbbc24.mp3"));
    mediaPlayer.start();
    // Create the Visualizer object and attach it to our media player.
    try{
        visual = new Visualizer(mediaPlayer.getAudioSessionId()); // this line causing Exception 
        visual.setEnabled(true);
        visual.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);
        }
        catch(Exception ex)
        {
            Log.e("Visual Ex", ex.getMessage());
        }
    }
}

Answer 1

I have same problem, so try to add permission in AndroidManifest.xml file

Also if you wan`t to see that audi wave, you hould show it in canvas or something ...

Working example :

//android.permission.MODIFY_AUDIO_SETTINGS for audio settings and also
//android.permission.INTERNET for internet streaming

package com.janilemy;

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.audiofx.Visualizer;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.SeekBar;
import android.widget.TextView;

import java.io.IOException;

public class AudioFxDemoActivity extends Activity {

    //Here is your URL defined
String url = "http://vprbbc.streamguys.net/vprbbc24.mp3";

    //Constants for vizualizator - HEIGHT 50dip
private static final float VISUALIZER_HEIGHT_DIP = 50f;

    //Your MediaPlayer
MediaPlayer mp;

//Vizualization
private Visualizer mVisualizer;

    private LinearLayout mLinearLayout;
    private VisualizerView mVisualizerView;
    private TextView mStatusTextView;


/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    //Info textView
    mStatusTextView = new TextView(this);

    //Create new LinearLayout ( because main.xml is empty )
    mLinearLayout = new LinearLayout(this);
    mLinearLayout.setOrientation(LinearLayout.VERTICAL);
    mLinearLayout.addView(mStatusTextView);

    //set content view to new Layout that we create
    setContentView(mLinearLayout);

    //start media player - like normal
    mp = new MediaPlayer();
    mp.setAudioStreamType(AudioManager.STREAM_MUSIC);

    try {
        mp.setDataSource(url); // set data source our URL defined
    } catch (IllegalArgumentException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IllegalStateException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }       

    try {   //tell your player to go to prepare state
        mp.prepare(); 
    } catch (IllegalStateException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
            //Start your stream / player
    mp.start();

    //setup your Vizualizer - call method
    setupVisualizerFxAndUI();        

            //enable vizualizer
            mVisualizer.setEnabled(true);

            //Info text
    mStatusTextView.setText("Playing audio...");
}

    //Our method that sets Vizualizer
private void setupVisualizerFxAndUI() {
    // Create a VisualizerView (defined below), which will render the simplified audio
    // wave form to a Canvas.

    //You need to have something where to show Audio WAVE - in this case Canvas
    mVisualizerView = new VisualizerView(this);
    mVisualizerView.setLayoutParams(new ViewGroup.LayoutParams(
            ViewGroup.LayoutParams.FILL_PARENT,
            (int)(VISUALIZER_HEIGHT_DIP * getResources().getDisplayMetrics().density)));
    mLinearLayout.addView(mVisualizerView);

    // Create the Visualizer object and attach it to our media player.
    //YOU NEED android.permission.RECORD_AUDIO for that in AndroidManifest.xml
    mVisualizer = new Visualizer(mp.getAudioSessionId());
    mVisualizer.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);
    mVisualizer.setDataCaptureListener(new Visualizer.OnDataCaptureListener() {
        public void onWaveFormDataCapture(Visualizer visualizer, byte[] bytes,
                int samplingRate) {
            mVisualizerView.updateVisualizer(bytes);
        }

        public void onFftDataCapture(Visualizer visualizer, byte[] bytes, int samplingRate) {}
    }, Visualizer.getMaxCaptureRate() / 2, true, false); 
}

@Override
protected void onPause() {
    super.onPause();

    if (isFinishing() && mp != null) {
        mVisualizer.release();
        mEqualizer.release();
        mp.release();
        mp = null;
    }
}

/**
 * A simple class that draws waveform data received from a
 * {@link Visualizer.OnDataCaptureListener#onWaveFormDataCapture }
 */
class VisualizerView extends View {
    private byte[] mBytes;
    private float[] mPoints;
    private Rect mRect = new Rect();

    private Paint mForePaint = new Paint();

    public VisualizerView(Context context) {
        super(context);
        init();
    }

    private void init() {
        mBytes = null;

        mForePaint.setStrokeWidth(1f);
        mForePaint.setAntiAlias(true);
        mForePaint.setColor(Color.rgb(0, 128, 255));
    }

    public void updateVisualizer(byte[] bytes) {
        mBytes = bytes;
        invalidate();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        if (mBytes == null) {
            return;
        }

        if (mPoints == null || mPoints.length < mBytes.length * 4) {
            mPoints = new float[mBytes.length * 4];
        }

        mRect.set(0, 0, getWidth(), getHeight());

        for (int i = 0; i < mBytes.length - 1; i++) {
            mPoints[i * 4] = mRect.width() * i / (mBytes.length - 1);
            mPoints[i * 4 + 1] = mRect.height() / 2
                    + ((byte) (mBytes[i] + 128)) * (mRect.height() / 2) / 128;
            mPoints[i * 4 + 2] = mRect.width() * (i + 1) / (mBytes.length - 1);
            mPoints[i * 4 + 3] = mRect.height() / 2
                    + ((byte) (mBytes[i + 1] + 128)) * (mRect.height() / 2) / 128;
        }

        canvas.drawLines(mPoints, mForePaint);
    }
}

}

This is a full working example of android media player audio wave visualization... I hope it will help you with your solution ...

Jani L