在AVPlayer中切换视频时更改时会创建Flash

5 回答

• 0

  我试过这个，它对我有用 .

  if (layerView1.playerLayer.superlayer) {
          [layerView1.playerLayer removeFromSuperlayer];
   }
  

  但我也在分配自己的AVPlayerLayer，而不是使用IB来完成它 .

  回复于 2024-06-02T17:04:53+08:00
• 0

  经过太多努力没有成功，我终于找到了一个解决方案，而不是最好的解决方案，但是有效

  我的输入代码如下，请看 loadVideo 方法

  #import "ViewController.h"
  #import <AVKit/AVKit.h>
  
  @interface ViewController ()<UIGestureRecognizerDelegate>
  @property (nonatomic, strong) NSArray *videos;
  @property (nonatomic, assign) NSInteger videoIndex;
  @property (nonatomic, strong) AVPlayer *player;
  @property (nonatomic, strong) AVPlayerLayer *playerLayer;
  @end
  
  @implementation ViewController
  
  - (void)viewDidLoad {
      [super viewDidLoad];
      self.view.backgroundColor = [UIColor blackColor];
      self.videos = @[@"1.mp4", @"2.mp4", @"3.mp4", @"4.mp4", @"5.mp4", @"6.mp4"];
      self.videoIndex = 0;
      [self loadVideo];
      [self configureGestures:self.view]; //changes video on swipe
  
  }
  
  -(void)prevZoomPanel{
      if(self.videoIndex <= 0){
          NSLog(@"cant go prev");
          return;
      }
      self.videoIndex -= 1;
      [self loadVideo];
  }
  
  -(void)nextZoomPanel{
      if(self.videoIndex >= self.videos.count - 1){
          NSLog(@"cant go next");
          return;
      }
      self.videoIndex += 1;
      [self loadVideo];
  }
  
  #pragma mark - Load Video
  -(void)loadVideo{
      NSURL * bundle = [[NSBundle mainBundle] bundleURL];
      NSURL * file = [NSURL URLWithString:self.videos[self.videoIndex] relativeToURL:bundle];
      NSURL * absoluteFile = [file absoluteURL];
      AVPlayerItem *item = [AVPlayerItem playerItemWithURL:absoluteFile];
  
      //*************
      //DO NOT USE '[self.player replaceCurrentItemWithPlayerItem:item]', it flashes, instead, initialize the instace again.
      //Why is replaceCurrentItemWithPlayerItem flashing but playerWithPlayerItem is NOT?
      // if you want to see the diferente, uncomment the code above
      self.player = [AVPlayer playerWithPlayerItem:item];
  //    if (self.player == nil) {
  //        self.player = [AVPlayer playerWithPlayerItem:item];
  //    }else{
  //        [self.player replaceCurrentItemWithPlayerItem:item];
  //    }
  
  
  
      //*************
      //create an instance of AVPlayerLayer and add it on self.view
      //afraid of this
      AVPlayerLayer *playerLayer = [AVPlayerLayer playerLayerWithPlayer:self.player];
      playerLayer.videoGravity = AVLayerVideoGravityResizeAspect;
      playerLayer.frame = self.view.layer.bounds;
      [self.view.layer addSublayer:playerLayer];
  
      //*************
      //play the video before remove the old AVPlayerLayer instance, at this time will have 2 sublayers
      [self.player play];
  
  
      NSLog(@"sublayers before: %zd", self.view.layer.sublayers.count);
  
  
      //*************
      //remove all sublayers after 0.09s, to avoid the flash, 0.08 still flashing.
      //TODO: tested on iPhone X, need to test on slower iPhones to check if the time is enough.
      //Why do I need to wait to remove? Is that safe? What if I swipe a lot too fast, faster than 0.09s ?
      dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.09 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
  
          NSArray* sublayers = [NSArray arrayWithArray:self.view.layer.sublayers];
          NSInteger idx = 0;
  
          for (CALayer *layer in sublayers) {
  
              if (idx < self.view.layer.sublayers.count && self.view.layer.sublayers.count > 1) {
  
                  //to avoid memory crash, need to remove all sublayer but keep the top one.
                  [layer removeFromSuperlayer];
              }
              idx += 1;
          }
  
          NSLog(@"sublayers after: %zd", self.view.layer.sublayers.count);
      });
  
  
  
      //*************
      //the code bellow is the same of the above, but with no delay
      //uncomment the code bellow AND comment the code above to test
  //    NSArray* sublayers = [NSArray arrayWithArray:self.view.layer.sublayers];
  //    NSInteger idx = 0;
  //
  //    for (CALayer *layer in sublayers) {
  //
  //        if (idx < self.view.layer.sublayers.count && self.view.layer.sublayers.count > 1) {
  //
  //            //to avoid memory crash, need to remove all sublayer but keep the top one.
  //            [layer removeFromSuperlayer];
  //        }
  //        idx += 1;
  //    }
  
  
  
      //*************
      //App's memory usage is about 14MB constantly, didn't increase on videos change.
      //TODO: need to test with more than 100 heavy videos.
  
  }
  
  
  
  
  -(void)configureGestures:(UIView *)view{
      UISwipeGestureRecognizer *right = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(userDidSwipeScreen:)];
      right.direction = UISwipeGestureRecognizerDirectionRight;
      right.delegate = self;
      [view addGestureRecognizer:right];
      UISwipeGestureRecognizer *left = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(userDidSwipeScreen:)];
      left.direction = UISwipeGestureRecognizerDirectionLeft;
      left.delegate = self;
      [view addGestureRecognizer:left];
  }
  
  - (void)userDidSwipeScreen:(UISwipeGestureRecognizer *)swipeGestureRecognizer{
      switch (swipeGestureRecognizer.direction) {
          case UISwipeGestureRecognizerDirectionLeft: [self nextZoomPanel];break;
          case UISwipeGestureRecognizerDirectionRight:[self prevZoomPanel];break;
          default: break;
      }
  }
  
  @end
  

  回复于 2024-06-02T17:04:53+08:00
• 3

  我找到了一个非常简单的解决方案（对于某些人来说可能太简单了，但对我来说它确实有效）：在Interface Builder中我 set the background color of my view （它附加了视频层） to black . 所以's just '闪现'黑色现在......

  回复于 2024-06-02T17:04:53+08:00
• -1

  我找到了两种解决方法 . 对我来说这两种方法都有效，而我更喜欢第二种方法 .

  首先，正如@Alex Kennberg所提到的，创建两组 AVPlayerLayer 和 AVPlayer . 在视频之间切换时切换它们 . 务必设置背景颜色以清除颜色 .

  其次，使用 UIImageView 作为 AVPlayerLayer 的所有者视图 . 在切换视频之前，创建视频的缩略图图像并将其设置为imageview . 务必正确设置视图模式 .

  回复于 2024-06-02T17:04:53+08:00
• 6

  您无需为此任务重新创建 AVPlayer . 您可以只有多个 AVPlayerItem 然后通过 [AVPlayer replaceCurrentItemWithPlayerItem:item] 切换哪一个是当前的 .

  此外，您可以使用以下代码观察当前项目的更改时间 .

  static void* CurrentItemObservationContext = &CurrentItemObservationContext;
  

  ...创建播放器后，注册观察者：

  [player1 addObserver:self 
                     forKeyPath:kCurrentItemKey 
                        options:NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew
                        context:CurrentItemObservationContext];
  

  ...

  - (void)observeValueForKeyPath:(NSString*) path 
                    ofObject:(id)object 
                      change:(NSDictionary*)change 
                     context:(void*)context {
       if (context == CurrentItemObservationContext) {
           AVPlayerItem *item = [change objectForKey:NSKeyValueChangeNewKey];
           if (item != (id)[NSNull null]) {
               [player1 play];
           }
       }
   }
  

  回复于 2024-06-02T17:04:53+08:00