在Android中启用相机时,音频播放会停止吗？

Question

我正在开发一个需要音频/视频聊天的应用...我的问题是当我开始捕捉视频时音频播放完全停止.

技术说明 我使用AudioTrack Class和AudioTrack.OnPlaybackPositionUpdateListener进行音频播放.我使用Camera和Camera.PreviewCallBack进行视频录制.

现在,一旦摄像头启动,AudioTrack类的回叫就会停止工作.我该怎么做才能解决这个问题？我有HTC的设备,它有Android2.2.

编辑 因为我不能在这里发布完整的代码...(我无法访问视频模块的代码),我在这里列出了这个场景: -

1. 音频聊天已经开始,音频正在播放,这意味着onPeriodicNotification()被正确调用..

public void start(){

    bufferSize = AudioTrack.getMinBufferSize(sampleRateInHz, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT);

    if (bufferSize != AudioTrack.ERROR_BAD_VALUE && bufferSize != AudioTrack.ERROR) {
        audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC, this.sampleRateInHz, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT,
                this.bufferSize, AudioTrack.MODE_STREAM);
        if (audioTrack != null && audioTrack.getState() == AudioTrack.STATE_INITIALIZED) {
            Log.i(LOG_TAG, "Audio Track instance created buffer Size : " + this.bufferSize);

            audioTrack.setPositionNotificationPeriod(320);
            audioTrack.setPlaybackPositionUpdateListener(this);

            // init All the jitter variables
            initVariables();
            // short[] tempBuf = shortBuffer;//new short[bufferSize / 2];
            audioTrack.write(shortBuffer, 0, shortBuffer.length);
            audioTrack.write(shortBuffer, 0, shortBuffer.length);
            audioTrack.write(shortBuffer, 0, shortBuffer.length);
            audioTrack.write(shortBuffer, 0, shortBuffer.length);
            audioTrack.write(shortBuffer, 0, shortBuffer.length);
            audioTrack.write(shortBuffer, 0, shortBuffer.length);
            // start playback of the audioTrack
            audioTrack.play();

        } else {
            Log.e(LOG_TAG, "Unble to create AudioTrack instance");
        }
    } else {
        Log.e(LOG_TAG, "Unable to get the minimum buffer size");
    }
}

@Override
    public void onPeriodicNotification(AudioTrack track) {
        try {
            fillAudio(shortBuffer);
            track.write(shortBuffer, 0, Constants.FRAME_SIZE / 2);
        } catch (NullPointerException nex) {
            nex.printStackTrace();
            Log.e(LOG_TAG, "Null Pointer inside periodic notification");
        }}

fillAudio()是一个填充缓冲区的函数...

1. 用户点击视频聊天按钮,使用相机Camera.open(),设置参数,回调,然后通过使用camera.startPreview().. 开始回调.

OnTouchListener cameraSurfaceOnTouch = new OnTouchListener(){int x = 0; int y = 0; int dx = 0; int dy = 0; boolean moving = false;

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            x = (int) event.getX();
            y = (int) event.getY();
            dx = (int) event.getX() - v.getLeft();
            dy = (int) event.getY() - v.getTop();
            moving = true;

            return true;
        case MotionEvent.ACTION_MOVE:
            if (moving) {
                x = (int) event.getX() - dx;
                y = (int) event.getY() - dy;

                x = Math.max(x, 0);
                x = Math.min(x, getWindowManager().getDefaultDisplay().getWidth() - v.getWidth());

                y = Math.max(y, 0);
                y = Math.min(y, getWindowManager().getDefaultDisplay().getHeight() - v.getHeight());

                v.layout(x, y, x + v.getWidth(), y + v.getHeight());
            }
            return true;
        case MotionEvent.ACTION_UP:
            x = (int) event.getX() - dx;
            y = (int) event.getY() - dy;

            x = Math.max(x, 0);
            x = Math.min(x, getWindowManager().getDefaultDisplay().getWidth() - v.getWidth());

            y = Math.max(y, 0);
            y = Math.min(y, getWindowManager().getDefaultDisplay().getHeight() - v.getHeight());

            // v.layout(x ,y,x + v.getMeasuredWidth() , y
            // +v.getMeasuredHeight());
            moving = false;
            return true;
        }
        // v.invalidate();
        return false;
    }
};

Callback videoPlayerCallBack = new Callback() {
    public void surfaceDestroyed(SurfaceHolder holder) {
        stopCapturerVideo();
        if (converterID != -1 && x264Wrapper != null) {
            x264Wrapper.destroyVideoFormate(converterID);
            converterID = -1;
        }
    }
private void startCapturerVideo() {
        if (m_CameraStatus == false) {
            this.m_CameraStatus = this.videoCapturer.startCamera();
        }
        synchronized (this.m_videoCapturerBufferList) {
            this.m_videoCapturerBufferList.clear();
        }

        byte[] tmp = new byte[10];
        tmp[0] = Constants.VIDEO_SESSION_STARTED;

        short width = 160;
        short height = 120;

        byte[] mIndex = CommonMethods.toByteArray(session.getSelfMeetingIndex());
        byte[] aWidth = CommonMethods.toByteArray(width);
        byte[] aHeight = CommonMethods.toByteArray(height);

        tmp[1] = mIndex[0];
        tmp[2] = mIndex[1];

        tmp[3] = aWidth[0];
        tmp[4] = aWidth[1];

        tmp[5] = aHeight[0];
        tmp[6] = aHeight[1];

        tmp[7] = 0;
        session.add(tmp, 8, 3);

        aWidth = null;
        aHeight = null;
        tmp = null;

        this.stopThread = false;
        this.encodeAndSendThread = new Thread(encodeAndSendRun);
        this.encodeAndSendThread.start();
        this.videoCapturer.startCaptureringVideo();

    }
   public boolean startCaptureringVideo() {
        boolean cameraStatus = true;
        Log.e(LOG_TAG,"startCaptureringVideo called ");
        if(this.mCamera != null)
        {
            try {
//              this.mCamera.setPreviewDisplay(this.videoCaptureViewHolder);
                this.mCamera.startPreview();
                } 
            catch (Throwable e) {
                cameraStatus = false;
                mCamera.release();
                mCamera = null;

                }
        }
        else
        {
            cameraStatus =false;
        }
        return cameraStatus;
    }

1. onPeriodicNotification() 即使我停下并松开相机,也不会在第2步之后再次调用.

可能的原因是什么,

Answer 1

检查AudioManager的onAudioFocusChange回调:

@Override
public void onAudioFocusChange(int focusChange) {
    if (focusChange == AudioManager.AUDIOFOCUS_LOSS_TRANSIENT) {
        //this audio focus change is made when you use the camera
    }
}

也许你在更改音频焦点时暂停音频,请查看它.