ios/IJKAVMoviePlayer add once token for ready to play status

ios/IJKMediaPlayer/IJKMediaPlayer/IJKAVMoviePlayerController.m

@@ -122,7 +122,7 @@ static void *KVO_AVPlayerItem_playbackBufferEmpty       = &KVO_AVPlayerItem_play
     IJKKVOController *_playerItemKVO;
     
     id _timeObserver;
-    
+    dispatch_once_t _readyToPlayToken;
     // while AVPlayer is prerolling, it could resume itself.
     // foring start could
     BOOL _isPrerolling;
@@ -726,6 +726,7 @@ static IJKAVMoviePlayerController* instance;
                 /* Once the AVPlayerItem becomes ready to play, i.e.
                  [playerItem status] == AVPlayerItemStatusReadyToPlay,
                  its duration can be fetched from the item. */
+                dispatch_once(&_readyToPlayToken, ^{
                     [_avView setPlayer:_player];
                     
                     self.isPreparedToPlay = YES;
@@ -742,6 +743,7 @@ static IJKAVMoviePlayerController* instance;
                     
                     if (_shouldAutoplay)
                         [_player play];
+                });
             }
                 break;