As mentioned, AVPlayer refuses to play local video files (videos are absolutely fine), but network loading links can be played. Could you please tell me what’s going on?

The code is as follows:

NSURL *url = [NSURL fileURLWithPath:@"/Users/tangkunyin/Desktop/mp4ForDownloadTest.mp4"];
AVAsset *movieAsset = [AVURLAsset assetWithURL:url];
AVPlayerItem *playerItem = [AVPlayerItem playerItemWithAsset:movieAsset];

AVPlayer *player = [AVPlayer playerWithPlayerItem:playerItem];

AVPlayerLayer *playerLayer = [AVPlayerLayer playerLayerWithPlayer:player];
playerLayer.frame = CGRectMake(0, 0, KDeviceWidth, 300);
playerLayer.videoGravity=AVLayerVideoGravityResize;

[self.view.layer addSublayer:playerLayer];

[player play];