Android：从视频中捕捉帧

Question

我想使用手机的相机录制视频，抓取并显示存储视频中的一帧。视频路径使用“sharedData.setValue（a）;”存储在全局变量中。目前，我的应用程序可以运行，录制视频和保存。但是，我无法从视频中捕获帧（下面的代码）。申请刚刚关闭。

捕获并保存视频代码：

   @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_camera2_video_image);

    createVideoFolder();
    createImageFolder();

    mChronometer = (Chronometer) findViewById(R.id.chronometer);
    mTextureView = (TextureView) findViewById(R.id.textureView);
    mStillImageButton = (ImageButton) findViewById(R.id.cameraImageButton2);
    mStillImageButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if(!(mIsTimelapse || mIsRecording)) {
                checkWriteStoragePermission();
            }
            lockFocus();
        }
    });

    Button btnProcess = (Button) findViewById(R.id.btnProcess);
    btnProcess.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(Camera2VideoImageActivity.this, FrameDisplay.class);
            startActivity(intent);
        }
    });


    mRecordImageButton = (ImageButton) findViewById(R.id.videoOnlineImageButton);
    mRecordImageButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (mIsRecording || mIsTimelapse) {
                mChronometer.stop();
                mChronometer.setVisibility(View.INVISIBLE);
                mIsRecording = false;
                mIsTimelapse = false;
                mRecordImageButton.setImageResource(R.mipmap.btn_video_online);

                // Starting the preview prior to stopping recording which should hopefully
                // resolve issues being seen in Samsung devices.
                startPreview();
                mMediaRecorder.stop();
                mMediaRecorder.reset();

                Intent mediaStoreUpdateIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
                mediaStoreUpdateIntent.setData(Uri.fromFile(new File(mVideoFileName)));
                String a = mediaStoreUpdateIntent.getDataString();
                Log.e("Path Saved: ", a);
                sharedData.setValue(a);

                sendBroadcast(mediaStoreUpdateIntent);

            } else {
                mIsRecording = true;
                mRecordImageButton.setImageResource(R.mipmap.btn_video_busy);
                checkWriteStoragePermission();
            }
        }
    });
    mRecordImageButton.setOnLongClickListener(new View.OnLongClickListener() {
        @Override
        public boolean onLongClick(View v) {
            mIsTimelapse =true;
            mRecordImageButton.setImageResource(R.mipmap.btn_timelapse);
            checkWriteStoragePermission();
            return true;
        }
    });
}

全局变量代码：

public class Globals {


private static Globals instance = new Globals();

// Getter-Setters
public static Globals getInstance() {
    return instance;
}

public static void setInstance(Globals instance) {
    Globals.instance = instance;
}

private String notification_index;


private Globals() {

}


public String getValue() {
    return notification_index;
}


  public void setValue(String notification_index) {
      this.notification_index = notification_index;
  }

}

显示帧位图代码：

public class FrameDisplay extends AppCompatActivity {

Globals sharedData = Globals.getInstance();
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_display_frame);

    String n = sharedData.getValue();
    ImageView imgView1 = (ImageView) findViewById(R.id.imgView);
    TextView textView = (TextView) findViewById(R.id.textView);

    Log.e("Path recieved: ",n);
    try{
        MediaMetadataRetriever retriever = new MediaMetadataRetriever();


 // Set data source to retriever.
 // From your code, you might want to use your 'String path' here.
    retriever.setDataSource(n);

 // Get a frame in Bitmap by specifying time.
 // Be aware that the parameter must be in "microseconds", not milliseconds.
        Bitmap bitmap = retriever.getFrameAtTime(10000);
        imgView1.setImageBitmap(bitmap);
        textView.setEnabled(false);
        }catch(Exception e){
            e.printStackTrace();
        }
        imgView1.setBackgroundResource(R.mipmap.btn_camera);
        textView.setEnabled(true);
    }
}