VideoView onResume loses buffered portion of the v

问题:

I am having an Activity in which there is

1. VideoView -- Streams a video from a webserver.

2. Button -- Takes the user to the next activity to be shown.

When the application starts, VideoView is made to play the Video from a webserver.

Now assume

 Total Video length is 60 Minutes

 Current Video progress is 20 Minutes

 Current Buffered progress 30 Minutes 

Now when I click on the above mentioned Button which takes user to the next activity.

From that Activity if i press the back button, Previous Activity(with VideoView and Button) appears in front of the user. But when resumed all the Buffered Portion of the video is lost and hence the VideoView starts playing the video from the beginning which is really bad. <-- Actual Problem

Problem

When Activity is resumed back, the buffered portion of the video is lost and hence starts buffering it again. So how to overcome re-buffering the buffered portion of the Video ?

Even official Youtube android app. has the same problem.

Edit 1 :

I tried the below code in Activity but its not working.

@Override
protected void onPause() {
    // TODO Auto-generated method stub
    super.onPause();
    videoView.suspend();
}

@Override
protected void onResume() {
    // TODO Auto-generated method stub
    super.onResume();
    videoView.resume();
}

Can anyone guide me regarding this problem ?. Or am I missing something to make this work perfectly ?

Current Workaround

I have saved the current playing position of the video in onPause() method and in onResume() method I have used that position to seek the video to that duration. This works fine. But the video buffering starts from the beginning tho it starts the video from the seek position.

Any help is deeply appreciated.

回答1:

I've spent several hours trying to hack the original VideoView source code and Now I can confirm VideoView can be hacked to behavior what you want - retain buffering after surface destroyed. I've tested on my Samsung Galaxy S2, which works as expected, in my case, the video buffering (streaming m4v video from remote http server) is successfully retained when I open a new activity and go back.

Basically, the workaround is create you own VideoView class (by copying the source code), and hack the SurfaceHolder.Callback() implementation. Bear in mind that VideoView use some internal/hide API, so if you want to create a copy of VideoView in your own project, you have to follow the inazaruk's article to enable using internal/hide API. As a quick hack, I just download inazaruk's build from here and use inazaruk-android-sdk-dbd50d4/platforms/android-15-internals/android.jar replace my original android.jar in my android-sdk/platforms/android-15/.

VideoView source code can be downloaded from GrepCode. Once you successfully create you own copy without compile error, change SurfaceHolder.Callback() to something like this:

private boolean videoOpened = false;

SurfaceHolder.Callback mSHCallback = new SurfaceHolder.Callback()
{

    ... ...

    public void surfaceCreated(SurfaceHolder holder)
    {
        Log.i(TAG, "---------------------> surface created.");
        mSurfaceHolder = holder;
        if (!videoOpened) {
          openVideo(); // <-- if first time opened, do something as usual, video is buffered.
          /** 
           * openVideo() actually mMediaPlayer.prepareAsync() is the first key point, it is
           * also called in other two VideoView's public methods setVideoURI() and resume(), 
           * make sure you don't call them in your activity.
           */ 
          videoOpened = true;
        } else {
          start();  // <-- if back from another activity, simply start it again.
        }
    }

    public void surfaceDestroyed(SurfaceHolder holder)
    {
        Log.i(TAG, "---------------------> surface destroyed.");
        // after we return from this we can't use the surface any more.
        mSurfaceHolder = null;
        if (mMediaController != null) mMediaController.hide();
        //release(true);
        /**
         * release() actually mMediaPlayer.release() is the second key point, it is also
         * called in other two VideoView's public methods stopPlayback() and suspend(), make
         * sure you don't call them in your activity.
         */
        pause(); // <-- don't release, just pause.
    }
};

And make sure you don't call videoView.resume(), videoView.setVideoURI(), videoView.suspend() and videoView.stopPlayback() explicitly in you MediaPlayerActivity like this:

@Override
protected void onResume() {
  if (videoView != null)
    videoView.resume();  // <-- this will cause re-buffer.
    super.onResume();
}

@Override
protected void onPause() {
  if (videoView != null)
    videoView.suspend(); // <-- this will cause clear buffer.
    super.onPause();
}

Note that I have just done a dirty hack to prove the feasibility, You should design and implement your VideoView class properly to avoid any side-effect.

Update:

As an alternative, you should able to achieve same effect using plain MediaPlayer create your MediaPlayerActivity if you don't want to do the interal/hide API stuff You can start with the MediaPlayerDemo_Video.java in ApiDemos sample. The key point is make sure prepare (result buffering) and release method is properly handled in both SurfaceHolder Callback methods and Activity life cycle method to avoid prepare/release video every time surface is created/destroyed, and Activity is started,resumed/paused,stopped. I've created a dummy BufferedMediaPlayerActivity (highly simplified for posting here) which contains only key parts and can be used for quick demonstration, it doesn't have MediaController, however, you can check from Logcat to see that the buffer percentage is actually keep increasing instead of rolling over from 0 every time you open new activity and go back.

BufferedMediaPlayerActivity.java:

package com.example;

import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnBufferingUpdateListener;
import android.media.MediaPlayer.OnPreparedListener;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class BufferedMediaPlayerActivity extends Activity implements OnPreparedListener, OnBufferingUpdateListener, SurfaceHolder.Callback {

  private static final String TAG = "BufferedMediaPlayerActivity";
  private int mVideoWidth;
  private int mVideoHeight;
  private MediaPlayer mMediaPlayer;
  private SurfaceView mPreview;
  private SurfaceHolder holder;
  private String path;
  private boolean mIsVideoReadyToBePlayed = false;

  @Override
  public void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    setContentView(R.layout.buffered_media_player);
    mPreview = (SurfaceView) findViewById(R.id.surface);
    holder = mPreview.getHolder();
    holder.addCallback(this);
    holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    holder.setFixedSize(mVideoWidth, mVideoHeight);
    // retrieve httpUrl passed from previous activity.
    path = getIntent().getExtras().getString("videoUrl");
  }

  @Override
  public void onDestroy() {
    super.onDestroy();
    if (mMediaPlayer != null) {
      mMediaPlayer.release();
      mMediaPlayer = null;
    }
    mIsVideoReadyToBePlayed = false;
  }

  private void playVideo() {
    mIsVideoReadyToBePlayed = false;
    try {
      // Create a new media player and set the listeners
      mMediaPlayer = new MediaPlayer();
      mMediaPlayer.setDataSource(path);
      mMediaPlayer.setDisplay(holder);
      mMediaPlayer.prepare();
      mMediaPlayer.setOnPreparedListener(this);
      mMediaPlayer.setOnBufferingUpdateListener(this);
      mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
    } catch (Exception e) {
      Log.e(TAG, "error: " + e.getMessage(), e);
    }
  }

  @Override
  public void onPrepared(MediaPlayer mediaplayer) {
    Log.d(TAG, "onPrepared called");
    mIsVideoReadyToBePlayed = true;
    if (mIsVideoReadyToBePlayed) {
      mMediaPlayer.start();
    }
  }

  @Override
  public void onBufferingUpdate(MediaPlayer mp, int percent) {
    Log.i(TAG, "---------------> " + percent);
  }

  @Override
  public void surfaceChanged(SurfaceHolder surfaceholder, int i, int j, int k) {
    Log.d(TAG, "surfaceChanged called");
  }

  @Override
  public void surfaceCreated(SurfaceHolder holder) {
    Log.d(TAG, "surfaceCreated called");
    if (!mIsVideoReadyToBePlayed)
      playVideo();
    else
      mMediaPlayer.start();
  }

  @Override
  public void surfaceDestroyed(SurfaceHolder surfaceholder) {
    Log.d(TAG, "surfaceDestroyed called");
    mMediaPlayer.pause();
  }

}

buffered_media_player.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="match_parent"
  android:layout_height="match_parent">

  <SurfaceView android:id="@+id/surface"
    android:layout_width="200dip"
    android:layout_height="160dip"
    android:layout_gravity="center">
  </SurfaceView>

</LinearLayout>

回答2:

I found a solution fix it:

VideoView videoView;
MediaPlayer mp;

videoView.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
            @Override
            public void onPrepared(MediaPlayer mp) {
                this.mp = mp;
            }
        });

public void pause(){
    //NOT videoview.pause();
    if (mp != null){
       mp.pause();
    }
}

public void resume(){
    //NOT videoview.resume();
    if (mp != null){
       mp.start();
    }   
}

It work for me, i sure it help you

回答3:

As the buffer is lost when the video view goes to the background(change in visibility), you should try blocking this behavior by overriding the onWindowVisibilityChanged method of VideoView. Call super only if the video view is becoming visible. May have side-effects.

public class VideoTest extends VideoView {

    public VideoTest(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    protected void onWindowVisibilityChanged(int visibility) {
        if (visibility == View.VISIBLE) { 
            super.onWindowVisibilityChanged(visibility);
        }
    }
}

回答4:

Have you tried seekto()

@Override
protected void onResume() {
    super.onResume();
    try{
        if (video_view != null) {
            video_view.seekTo(position);    
            video_view.start();
        }
    }catch (Exception e) {
                }
}

@Override
protected void onPause() {
    super.onPause();    
    try{
        if (video_view != null) {
            position = video_view.getCurrentPosition();
            video_view.pause();         
        }
    }catch (Exception e) {
                }
}

回答5:

The problem with videoView.resume() in onResume() can be seen here: VideoView.resume(). VideoView.resume() calls openVideo() which first releases any previous MediaPlayer instances and then starts a new one. I cannot see an easy way out of this.

I see two possibilities:

• Write your own VideoView which retains the MediaPlayer instance for as long as you want. Or just take the source and modify to your liking, it's open source (check the license, though).
• Create a network proxy in your app which stands between the VideoView and the web server. You point your proxy to the web server and the VideoView to the proxy. The proxy starts downloading the data, saves it continuously for later use and passes it to the listening MediaPlayer (which was started by the VideoView). When the MediaPlayer disconnects, you keep the already downloaded data, so that when the MediaPlayer restarts the playback, you don't have to download it again.

Have fun! :)

回答6:

I've worked out a version that does not require a custom VideoView or manual configuration change handling. See Android VideoView orientation change with buffered video for an explanation.

回答7:

@Override
protected void onPause() {
    // TODO Auto-generated method stub
    videoView.pause();
    super.onPause();
}

@Override
protected void onRestart() {
    // TODO Auto-generated method stub
    videoView.resume();
    super.onPause();
}

try by adding above twomethods in your activity.

回答8:

You've mentioned two separate problems, and while I don't know how to keep the buffered video, You can still avoid starting from the beginning by calling getCurrentPosition in onPause and seekTo on onResume. This call is asynchronous, but it might give you a partial solution.

回答9:

public class Video_play extends Activity {
    VideoView vv;
   String URL;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.play_video);
        URL= getIntent().getStringExtra("URL");

        vv=(VideoView)findViewById(R.id.videoView1);
        MediaController mediaController = new MediaController(this);
        mediaController.setAnchorView(vv);
        Log.v("URL",URL);


//       Uri uri = Uri.parse(URL);
//        vv.setVideoURI(uri);
        vv.setMediaController(new MediaController(this));
        vv.setVideoPath(URL);

//        vv.requestFocus();
//       
//        vv.start();


//      Uri uri=Uri.parse(URL);
//
//    
//      vv.setVideoURI(uri);
        vv.start();
    }

回答10:

In onPause() function, instead of

@Override
protected void onPause() {
    // TODO Auto-generated method stub
    super.onPause();
    videoView.suspend();
}

try

@Override
protected void onPause() {
    // TODO Auto-generated method stub
    super.onPause();
    videoView.pause();
}