Question

我正在使用Android开发（SDK 2.2），我希望使用mediaRecorder进行视频录制，同时在每个预览框架上执行一些处理。

我在项目中使用MediaRecorder录制视频，在另一个中使用onPreviewFrame(byte[] data，Camera camera）（来自PreviewCallback）处理预览图片。

我尝试创建一个相机，并将其与mediaRecorder（setCamera函数）一起使用，但它不起作用。

有可能同时做两件事吗？

其实我不明白如何联系两件事？

我的代码：

package ch.fraise;

import java.io.IOException;
import android.app.Activity;
import android.hardware.Camera;
import android.hardware.Camera.PreviewCallback;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class CameraActivity extends Activity implements SurfaceHolder.Callback,
    Camera.AutoFocusCallback {

private SurfaceView preview;
private SurfaceHolder previewHolder;

private MediaRecorder mRecorder;
private Camera mCamera;
private boolean mPreviewRunning = false;
private boolean mCaptureFrame = false;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Log.e("", "Begin onCreate");
    setContentView(R.layout.main);

    preview = (SurfaceView) findViewById(R.id.surfaceView1);
    previewHolder = preview.getHolder();
    previewHolder.addCallback(this);
    previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

    mRecorder = new MediaRecorder();
}

@Override
public void onResume() {
    super.onResume();
}

@Override
public void onPause() {
    super.onPause();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.capture_menu, menu);
    return true;
}

public void startRecording() {
    Log.e("", "Begin StartRecording");
    mCaptureFrame = true;
    mRecorder.start();
}

public void stopRecording() {
    Log.e("", "Begin StopChange");
    mRecorder.stop();
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle item selection
    switch (item.getItemId()) {
    case R.id.startRecording:
        startRecording();
        return true;
    case R.id.stopRecording:
        stopRecording();
        return true;
    default:
        return super.onOptionsItemSelected(item);
    }
}

@Override
public void surfaceCreated(SurfaceHolder holder) {
    Log.e("", "Begin surfaceDestroy");
    mCamera = Camera.open();
}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    mCamera.stopPreview();
    mPreviewRunning = false;
    mCamera.release();

    mRecorder.reset();
    mRecorder.release();
}

@Override
public void onAutoFocus(boolean success, Camera camera) {
    // TODO Auto-generated method stub

}

/*
 * PreviewCallback()
 * 
 * this callback captures the preview at every frame and puts it in a byte
 * buffer. we will evaluate if this is a frame that we want to process, and
 * if so, we will send it to an asynchronous thread that will process it to
 * an ARGB Bitmap and POST it to the server
 */
PreviewCallback previewCallback = new PreviewCallback() {
    public void onPreviewFrame(byte[] data, Camera camera) {
        Log.e("", "onPreviewFrame pass");
        if (mCaptureFrame) {
            mCaptureFrame = false;
            // new FrameHandler().execute(data);
        }
    }
};

@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
        int height) {
    Log.e("", "Begin SurfaceChange");

    mRecorder.reset();
    mRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
    mRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
    mRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP);
    mRecorder.setOutputFile("/sdcard/videotest2.mp4");
    mRecorder.setVideoFrameRate(30);

    mRecorder.setPreviewDisplay(previewHolder.getSurface());
    try {
        mRecorder.prepare();
    } catch (IllegalStateException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    if (mPreviewRunning)
        mCamera.stopPreview();

    Camera.Parameters p = mCamera.getParameters();
    // p.setPreviewSize(width, height);
    mCamera.setParameters(p);

    try {
        mCamera.setPreviewDisplay(holder);
    } catch (IOException e) {
        e.printStackTrace();
    }

    mCamera.setPreviewCallback(previewCallback);

    mCamera.startPreview();
    mPreviewRunning = true;

}

}

和XML文件中的权限：

<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.RECORD_VIDEO" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

Answer 1

尤里卡！诀窍是将PreviewCallback附加到surfaceChanged(...) SurfaceHolder.Callback！执行此操作后，您将在MediaRecorder运行后继续获取预览帧数据！

例如：

public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
    mCamera.setPreviewCallback(new PreviewCallback() {
            public void onPreviewFrame(byte[] _data, Camera _camera) {
                Log.d("onPreviewFrame-surfaceChanged",String.format("Got %d bytes of camera data", _data.length));
            }
        });

}

Answer 2

录制时无法访问视频流，一旦开始录制，onPreviewFrame将无法调用。奇怪的是，onPreviewFrame似乎在你录制后不会被调用...

Answer 3

您只需将标记添加到清单文件中即可。它将起作用。示例代码如下所示。

例如： -

   </application>
    <uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.RECORD_VIDEO" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    ***<uses-feature android:name="android.hardware.camera" />***
</manifest>

Answer 4

如果您使用的是OS 2.2或更高版本，则使用此方法您的准备失败，其他异常将被删除

 public boolean startRecording() {
    try {
        camera.unlock();

        mediaRecorder = new MediaRecorder();
        mediaRecorder.setCamera(camera);
        mediaRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
        mediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
        mediaRecorder.setProfile(CamcorderProfile
                .get(CamcorderProfile.QUALITY_HIGH));

        File tempFile = new File(getOutputMediaFile(MEDIA_TYPE_VIDEO)
                .toString());

        mediaRecorder.setOutputFile(tempFile.getPath());
        mediaRecorder.setVideoFrameRate(videoFramesPerSecond);
        mediaRecorder.setVideoSize(surfaceView.getWidth(),
                surfaceView.getHeight());
        mediaRecorder.setPreviewDisplay(surfaceHolder.getSurface());
        mediaRecorder.setMaxFileSize(maxFileSizeInBytes);
        mediaRecorder.prepare();
        mediaRecorder.start();

        return true;
    } catch (IllegalStateException e) {
        Log.e(TAG, e.getMessage());
        e.printStackTrace();
        return false;
    } catch (IOException e) {
        Log.e(TAG, e.getMessage());
        e.printStackTrace();
        return false;
    }
}

视频录制时的Android预览处理

4 个答案: