player.duration在MPMoviePlayerController中为视频文件显示始终为零 [英] player.duration shows always zero in MPMoviePlayerController for video file

问题描述

我正在使用此代码在mpmediaplayer控制器中播放一个小视频

I am playing a small video in mpmediaplayer controller using this code

MPMoviePlayerController *player = [[MPMoviePlayerController alloc] 
                                   initWithContentURL:[NSURL fileURLWithPath:videostr]]; 

其中videostr是该视频文件的路径。

where videostr is path of that video file.

现在我需要获取该视频文件的长度，因为我正在使用此代码。

Now i need to get length of that video file for that i am using this code.

length = player.duration;

但它总是显示0.000。但视频播放效果很好。

But it always shows 0.000. But the video is playing well.

我正在通过谷歌搜索每个代码来获取视频时长仅 player.duration 。

I am checking by googling every where code to get video duration is player.duration only.

我还尝试了其他一些代码

And i try some other code also

AVURLAsset *asset = [[[AVURLAsset alloc] initWithURL:[NSURL fileURLWithPath:videostr] 
                                             options:[NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES], AVURLAssetPreferPreciseDurationAndTimingKey, nil]] autorelease];
NSTimeInterval duration; 
if (asset) 
    duration = CMTimeGetSeconds(asset.duration) ;
NSLog(@">>>>>>>>>>>>>>>>>>>> %f", asset.duration);

即使它显示为零。任何人都可以帮助我。

even though it shows zero.Can any one please help me.

提前感谢。

推荐答案

在内容实际可播放之前，您无法获得有用的持续时间。

You can not get a useful duration until the content is actually playable.

注册加载状态更改：

[[NSNotificationCenter defaultCenter] addObserver:self 
                                         selector:@selector(MPMoviePlayerLoadStateDidChange:) 
                                             name:MPMoviePlayerLoadStateDidChangeNotification 
                                           object:nil];

收到通知后评估州：

- (void)MPMoviePlayerLoadStateDidChange:(NSNotification *)notification
{
    if ((player.loadState & MPMovieLoadStatePlaythroughOK) == MPMovieLoadStatePlaythroughOK)
    {
        NSLog(@"content play length is %g seconds", player.duration);
    }
}

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