ios - 在 AVPlayer 中播放视频

Question

我的应用目前在功能上同时播放 2 个视频，但我看到的所有 SO 答案都使用了大量键值代码。如果我只做下面列出的最低限度，这是不好/错误的吗？

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 AVURLAsset *asset = [AVURLAsset assetWithURL:[NSURL URLWithString:firstVideo.videoURL]];
    AVPlayerItem *item = [AVPlayerItem playerItemWithAsset:asset];
    self.player1 = [AVPlayer playerWithPlayerItem:item];
    [topPlayer setMovieToPlayer:self.player1];


    AVURLAsset *asset2 = [AVURLAsset assetWithURL:[NSURL URLWithString:secondVideo.videoURL]];
    AVPlayerItem *item2 = [AVPlayerItem playerItemWithAsset:asset2];
    self.player2 = [AVPlayer playerWithPlayerItem:item2];
    [bottomPlayer setMovieToPlayer:self.player2];

    ((AVPlayerLayer *)[self.topPlayer layer]).videoGravity = AVLayerVideoGravityResizeAspectFill;
    ((AVPlayerLayer *)[self.bottomPlayer layer]).videoGravity = AVLayerVideoGravityResizeAspectFill;
    [self.player1 play];
    [self.player2 play];

上面的代码是我用来播放视频的所有代码，效果很好。偶尔会有 ~1s 的延迟，我怎么能等到两个视频都准备好播放，然后同时播放它们呢？

Answer 1

使用KVO观察播放器的状态，当两者都准备就绪时播放视频。

[yourPlayerItem addObserver:self forKeyPath:@"status" options:NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew context:nil];

在 kvo 中:

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if ([keyPath isEqualToString:@"status"]) {
        AVPlayerStatus status = [change[NSKeyValueChangeNewKey] integerValue];
        switch (status) {
            case AVPlayerStatusUnknown:
                //do something
                break;
            case AVPlayerStatusReadyToPlay:
            {
                //check which avplayer is ready, by check the parametric object isEqual:yourPlayerItem
                //use a bool value to record the ready status. after two bools are YES, then play the video
            }
                break;
            case AVPlayerStatusFailed:
            {
                AVPlayerItem *playerItem = (AVPlayerItem *)object;
                [self assetFailedToPrepareForPlayback:playerItem.error];
            }
                break;

        }
    }
}