我正在尝试播放视频的exo播放器，但它给我这个错误：-
E/外部播放器实施内部：来源错误。
无效响应代码异常：响应代码：404
这是我的活动类：-

public class VideoActivity extends AppCompatActivity implements VideoRendererEventListener {
    private String mVideoUrl;
    private SimpleExoPlayerView simpleExoPlayerView;
    private SimpleExoPlayer player;
    private static final String TAG = "AMAN";

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

    if (getIntent() != null)
        mVideoUrl = getIntent().getStringExtra("VideoUrl");

    BandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
    TrackSelection.Factory videoTrackSelectionFactory = new AdaptiveTrackSelection.Factory(bandwidthMeter);
    TrackSelector trackSelector = new DefaultTrackSelector(videoTrackSelectionFactory);

    LoadControl loadControl = new DefaultLoadControl();

    player = ExoPlayerFactory.newSimpleInstance(this, trackSelector, loadControl);
    simpleExoPlayerView = new SimpleExoPlayerView(this);
    simpleExoPlayerView = (SimpleExoPlayerView) findViewById(R.id.player_view);

    simpleExoPlayerView.setUseController(true);
    simpleExoPlayerView.requestFocus();

    simpleExoPlayerView.setPlayer(player);

    Uri mp4VideoUri =Uri.parse(mVideoUrl);

    DefaultBandwidthMeter bandwidthMeterA = new DefaultBandwidthMeter();

    DefaultDataSourceFactory dataSourceFactory = new DefaultDataSourceFactory(this, Util.getUserAgent(this, "exoplayer2example"), bandwidthMeterA);

    ExtractorsFactory extractorsFactory = new DefaultExtractorsFactory();

    MediaSource videoSource = new HlsMediaSource(mp4VideoUri, dataSourceFactory, 1, null, null);
    final LoopingMediaSource loopingSource = new LoopingMediaSource(videoSource);

   player.prepare(loopingSource);
                    player.setPlayWhenReady(true);

}

有人知道这里出了什么问题吗？