如何在android中通过编程方式捕获无音频的视频？

import android.hardware.Camera;
import android.media.CamcorderProfile;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.Button;

import java.io.File;
import java.io.IOException;

public class MainActivity extends AppCompatActivity implements SurfaceHolder.Callback {

    private Camera mCamera;
    private SurfaceView mPreview;
    private MediaRecorder mMediaRecorder;
    private Button mRecordButton;
    private boolean isRecording = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mPreview = findViewById(R.id.surfaceView);
        mRecordButton = findViewById(R.id.recordButton);
        mRecordButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (isRecording) {
                    stopRecording();
                } else {
                    startRecording();
                }
            }
        });

        SurfaceHolder holder = mPreview.getHolder();
        holder.addCallback(this);
    }

    private void startRecording() {
        mCamera.unlock();
        mMediaRecorder = new MediaRecorder();
        mMediaRecorder.setCamera(mCamera);
        mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
        mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
        mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
        mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.DEFAULT);
        mMediaRecorder.setOutputFile(getOutputMediaFile().toString());

        try {
            mMediaRecorder.prepare();
            mMediaRecorder.start();
            isRecording = true;
            mRecordButton.setText("Stop");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private void stopRecording() {
        mMediaRecorder.stop();
        mMediaRecorder.reset();
        mMediaRecorder.release();
        mCamera.lock();
        isRecording = false;
        mRecordButton.setText("Record");
    }

    private File getOutputMediaFile() {
        File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
                Environment.DIRECTORY_DCIM), "Camera");

        if (!mediaStorageDir.exists()) {
            if (!mediaStorageDir.mkdirs()) {
                return null;
            }
        }

        String timeStamp = String.valueOf(System.currentTimeMillis());
        return new File(mediaStorageDir.getPath() + File.separator +
                "VID_" + timeStamp + ".mp4");
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        mCamera = Camera.open();
        mCamera.setDisplayOrientation(90);
        try {
            mCamera.setPreviewDisplay(holder);
            mCamera.startPreview();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        if (holder.getSurface() == null) {
            return;
        }

        try {
            mCamera.stopPreview();
        } catch (Exception e) {
            e.printStackTrace();
        }

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

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        mCamera.release();
    }
}