在应用程式内播放影片？ [英] Playing video from within app?

问题描述

我想使用AVPlayer从我的应用程式播放本地影片。我看到无处不在，但找不到任何有用的教程/演示/文档。这是我正在尝试，但它不是玩。任何想法为什么？网址有效，因为我使用相同的视频，并使用MPMoviePlayer成功播放视频。

I am trying to play a local video from my app using AVPlayer. I have looked everywhere but can't find any useful tutorials/demos/documentation. Here is what I am trying, but it is not playing. Any idea why? The URL is valid because I was using the same one to play a video using MPMoviePlayer successfully.

       Video *currentVideo = [videoArray objectAtIndex:0];

    NSString *filepath = currentVideo.videoURL;
    NSURL *fileURL = [NSURL fileURLWithPath:filepath];

    AVURLAsset *asset = [AVURLAsset assetWithURL: fileURL];
    AVPlayerItem *item = [AVPlayerItem playerItemWithAsset: asset];
    self.player = [[AVPlayer alloc] initWithPlayerItem: item];


    AVPlayerLayer *layer = [AVPlayerLayer playerLayerWithPlayer:self.player];
    self.player.actionAtItemEnd = AVPlayerActionAtItemEndNone;


    layer.frame = CGRectMake(0, 0, 1024, 768);
    [self.view.layer addSublayer: layer];


    [self.player play];

推荐答案

我相信问题是，在执行此行 AVURLAsset * asset = [AVURLAsset assetWithURL：fileURL]; 后，该资产即可使用。这不是 AV基础编程指南：

I believe the problem is that you're assuming that after executing this line AVURLAsset *asset = [AVURLAsset assetWithURL: fileURL]; the asset is ready to use. This is not the case as noted in the AV Foundation Programming Guide:

    You create an asset from a URL using AVURLAsset. Creating the asset, however, 
    does not necessarily mean that it’s ready for use. To be used, an asset must 
    have loaded its tracks.

创建资源后尝试加载资源：

After creating the asset try loading it's tracks:

AVURLAsset *asset = [AVURLAsset URLAssetWithURL:fileURL options:nil];
NSString *tracksKey = @"tracks";

[asset loadValuesAsynchronouslyForKeys:@[tracksKey] completionHandler:
 ^{
     NSError *error;
     AVKeyValueStatus status = [asset statusOfValueForKey:tracksKey error:&error];

     if (status == AVKeyValueStatusLoaded) { 

         // At this point you know the asset is ready
         self.playerItem = [AVPlayerItem playerItemWithAsset:asset];

         ...
     }
 }];

请参阅此链接查看完整示例。

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