Android AudioRecord - 第二次不会初始化

Question

Hej,我目前正试图让AudioRecord工作.因为我需要一个更大的项目.但它似乎搞得很多.我一直在尝试很多东西,所以当我追踪这个bug时我回到了基础.我正在使用我的三星Galaxy S作为我的调试设备.

我的问题是,第一次重启我的设备后,我可以初始化我创建的AudioRecord对象没有问题.但是第二次运行它时,它不会初始化AudioRecord对象.我已经尝试了几个频率,fyi.

这是我的代码:

package android.audiorecordtest;

import android.app.Activity;
import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class AudioRecordTest extends Activity {

    int frequency;
    AudioRecord audRec;
    TextView txtVw;

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


        frequency=8000;
        int bufferSize=(AudioRecord.getMinBufferSize(frequency, AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT))*2;
        if (bufferSize>0) {
            audRec = new AudioRecord(MediaRecorder.AudioSource.MIC, frequency, AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT, bufferSize);
                int status = audRec.getState();
        if (status == AudioRecord.STATE_INITIALIZED) {
            txtVw.setText("Initialized" + frequency);
        } else {
            txtVw.setText("Not Initialized i=" + frequency);
        }
        }

经过几个小时的浏览logcat信息后,我发现了这个事件

    02-28 10:46:37.048: DEBUG/dalvikvm(4477): GC_EXPLICIT freed 1801 objects / 98944 bytes in 97ms
02-28 10:46:37.048: VERBOSE/AudioRecord(4477): stop

这似乎"释放了对AudioRecord的本机保留.所以我尝试使用我的Audiorecord object.release()完成覆盖最终化.虽然这没有工作..任何人有任何想法？

Answer 1

我能够重现你的问题(在三星手机上).我添加了一个释放记录的onDestroy()方法:

@Override
public void onDestroy() { 
    super.onDestroy();
    System.out.println("OnDestroy");
    audRec.release();
}

添加此项后,每次启动活动时,audioRecord似乎都会正确初始化.

Answer 2

我有同样的问题,通常audRec.release()确实有帮助,但如果你需要停止并启动几次,下面的代码更健壮.另外,我遇​​到了一个问题,即录制发生在一个单独的线程中,Android有时会在运行很长时间后杀死线程.所以看一下这段代码,它确保即使在另一个线程已经死亡时也能保持记录,并且在下面的audRec.start()中它停止并释放:

import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.MediaRecorder; 

public class RecorderSingleton {

    private static final int FREQUENCY = 16000;

    public static RecorderSingleton instance = new RecorderSingleton();
    private AudioRecord recordInstance = null;
    private int bufferSize;

    private RecorderSingleton() {
        bufferSize = AudioRecord.getMinBufferSize(FREQUENCY, AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT);
    }

    public boolean init() {
        recordInstance = new AudioRecord(MediaRecorder.AudioSource.MIC, FREQUENCY, AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT, bufferSize);
        if (recordInstance.getState() == AudioRecord.STATE_UNINITIALIZED) {
            return false;
        }
        return true;
    }

    public int getBufferSize() {
        return bufferSize;
    }
    public boolean start() {
        if (recordInstance != null && recordInstance.getState() != AudioRecord.STATE_UNINITIALIZED) {
            if (recordInstance.getRecordingState() != AudioRecord.RECORDSTATE_STOPPED) {
                recordInstance.stop();
            }
            recordInstance.release();
        }
        if (!init()) {
            return false;
        }
        recordInstance.startRecording();
        return true;
    }

    public int read(short[] tempBuffer) {
        if (recordInstance == null) {
            return AudioRecord.ERROR_INVALID_OPERATION;
        }
        int ret = recordInstance.read(tempBuffer, 0, bufferSize);
        return ret;
    }

    public void stop() {
        if (recordInstance == null) {
            return;
        }
        recordInstance.stop();
        recordInstance.release();
    }
}

然后,如果您有一个记录器线程,您可以按如下方式使用它:

import android.media.AudioRecord;

public class Recorder implements Runnable {
    private int requiredSamples;
    private int takenSamples = 0;
    private boolean cancelled = false;

    public void run() {

        // We're important...
        android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO);

        int bufferRead = 0;
        int bufferSize = RecorderSingleton.instance.getBufferSize();
        short[] tempBuffer = new short[bufferSize];
        if (!RecorderSingleton.instance.start()) {
            return;
        }
        try {
            Log.d(RoomieConstants.LOG_TAG, "Recorder Started");
            while (takenSamples < requiredSamples && !cancelled) {
                bufferRead = RecorderSingleton.instance.read(tempBuffer);
                if (bufferRead == AudioRecord.ERROR_INVALID_OPERATION) {
                    throw new IllegalStateException("read() returned AudioRecord.ERROR_INVALID_OPERATION");
                } else if (bufferRead == AudioRecord.ERROR_BAD_VALUE) {
                    throw new IllegalStateException("read() returned AudioRecord.ERROR_BAD_VALUE");
                }
                takenSamples += bufferRead;
                // do something with the samples ...
                // ...
                // ...
            }
        } finally {
            // Close resources...
            stop();
        }
    }

    public void stop() {
        RecorderSingleton.instance.stop();
    }

    public void cancel() {
        cancelled  = true;
    }
}