下载丢失的编解码器?

https://github.com/brianwernick/ExoMedia 播放器是android的一种外挂播放器。我认为它不支持编解码器,只会播放音频或什么都没有。如何让它(甚至操作系统)下载丢失的编解码器?

代码本身很简单:

 class MediaPlayerActivity : AppCompatActivity(), OnPreparedListener {

    private var uri: String = ""

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_media_player)
        uri = intent.getStringExtra("uri")

        setupVideoView(uri)
    }

    private fun setupVideoView(uri: String) {
        videoView.setOnPreparedListener(this)
        videoView.setVideoURI(Uri.parse(uri))
    }

    override fun onPrepared() {
        //Starts the video playback as soon as it is ready
        videoView.start()
    }

}

<?xml version="1.0" encoding="utf-8"?>


<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/black">

    <com.devbrackets.android.exomedia.ui.widget.VideoView
        android:id="@+id/videoView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:useDefaultControls="true" />

</RelativeLayout>

我也在android设备上安装了mx播放器,mx播放器没有提供安装编解码器的服务。相反,它只播放音频,没有视频。另外,如果我打开的mp4在铬它发挥良好。