请教官方！请教官方！！！关于视频录像文件尺寸的问题 ，我用java写了一段代码，调用原生录像，视频文件很小，但怎么把这段代码转为NJS代码？

package com.example.videotest;  

import java.io.File;  

import android.app.Activity;  
import android.hardware.Camera;  
import android.media.MediaRecorder;  
import android.media.MediaRecorder.AudioSource;  
import android.media.MediaRecorder.VideoSource;  
import android.os.Bundle;  
import android.os.Environment;  
import android.view.SurfaceHolder;  
import android.view.SurfaceHolder.Callback;  
import android.view.SurfaceView;  
import android.view.View;  

public class MainActivity extends Activity {  
    private SurfaceHolder mSurfaceHolder; // 画布的遥控器  
    private MediaRecorder mMediaRecorder; // 刻录机  
    private Camera mCamera; // 硬件  
    private SurfaceView mSurfaceView; // 画布（预览） 创建/改变/销毁  

    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_main);  
        mSurfaceView = (SurfaceView) findViewById(R.id.surfaceview); // 获取画布的引用  
        mSurfaceHolder = mSurfaceView.getHolder(); // 只能遥控器才可以控制画布  
        mSurfaceHolder.addCallback(new CustomCallBack()); // 回调: 创建/改变/销毁  
        // mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);  
    }  

    /**  
     * 预览/停止控制  
     * @param view  
     */  
    public void stop(View view) {  
        mMediaRecorder.setPreviewDisplay(null); // release resouce  
        mMediaRecorder.stop();  
        mMediaRecorder.release();  
        freeCameraResource();  
    }  

    private class CustomCallBack implements Callback {  
        @Override  
        public void surfaceCreated(SurfaceHolder holder) {  
            initCamera();  
        }  

        @Override  
        public void surfaceChanged(SurfaceHolder holder, int format, int width,  
                int height) {  
        }  

        @Override  
        public void surfaceDestroyed(SurfaceHolder holder) {  
            if (mCamera != null) {  
                mCamera.setPreviewCallback(null);  
                mCamera.stopPreview();  
                mCamera.lock();  
                mCamera.release();  
                mCamera = null;  
            }  
        }  
    }  

    private void initCamera() {  
        if (mCamera != null) {  
            freeCameraResource();  
        }  
        try {  
            mCamera = Camera.open();  
            mCamera.setDisplayOrientation(90);  
            mCamera.setPreviewDisplay(mSurfaceHolder);  
            mCamera.startPreview();  
            mCamera.unlock();  
        } catch (Exception e) {  
            e.printStackTrace();  
            freeCameraResource();  
        }  
    }  

    private void freeCameraResource() {  
        if (mCamera != null) {  
            mCamera.setPreviewCallback(null);  
            mCamera.stopPreview();  
            mCamera.lock();  
            mCamera.release();  
            mCamera = null;  
        }  
    }  

    /**  
     * 刻录  
     *   
     */  

    public void start(View view) {  
        mMediaRecorder = new MediaRecorder();  
        mMediaRecorder.reset();  
        if (mCamera != null)  
            mMediaRecorder.setCamera(mCamera);  
        mMediaRecorder.setPreviewDisplay(mSurfaceHolder.getSurface());  
        mMediaRecorder.setVideoSource(VideoSource.CAMERA);// 视频源  
        mMediaRecorder.setAudioSource(AudioSource.MIC);// 音频源  
        mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);// 视频输出格式  
        // mMediaRecorder.setVideoSize(mWidth, mHeight);// 设置分辨率：  
        mMediaRecorder.setVideoFrameRate(20);  
        mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);  
        mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);  
        mMediaRecorder.setVideoEncodingBitRate(512 * 1024);  
        mMediaRecorder.setOrientationHint(90);// 输出旋转90度，保持竖屏录制  
        mMediaRecorder.setMaxDuration(15000);// 最大期限  
        mMediaRecorder.setOutputFile(Environment.getExternalStorageDirectory()  
                + File.separator + "test.mp4");  
        try {  
            mMediaRecorder.prepare();  
            mMediaRecorder.start();  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
    }  
}