如果视频文件损坏，MPMoviePlayerViewController会返回错误吗？

Question

我正在下载视频并将其保存在某个目录中，以便用户随后可以播放该文件。

它适用于所有情况，如下载停止和由于某些网络波动再次恢复。但有时文件已完全下载但未在MPMoviePlayerViewController中播放。

我正在使用ASIHTTPRequest在后台下载视频文件。

观察：可能在下载时，网络波动一些，文件可能已损坏。

问题：我如何才知道下载的文件已损坏？ （通过MPMoviePlayerViewController）

有什么建议？以下是要播放的代码：

@ACB ...我使用了你的代码，但它始终处于其他条件：

    playerViewController = [[MPMoviePlayerViewController alloc]initWithContentURL:url];

    player = [playerViewController moviePlayer];
    player.movieSourceType = MPMovieSourceTypeFile;
    [player prepareToPlay];

    if(player.loadState == MPMovieLoadStatePlayable)
    {
        playerViewController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
        [self presentMoviePlayerViewControllerAnimated:playerViewController];


        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playerInterruptByUser:) name:MPMoviePlayerPlaybackStateDidChangeNotification object:playerViewController.moviePlayer];

        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playerFinished:) name:MPMoviePlayerPlaybackDidFinishNotification object:playerViewController.moviePlayer];

        //[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playerFinished:) name:UIApplicationDidEnterBackgroundNotification object:playerViewController.moviePlayer];

        [player play];
    }
    else
    {
        corruptVideoAlert = [[UIAlertView alloc]initWithTitle:NSLocalizedString(@"Corrupt Video", nil) message:NSLocalizedString(@"This video is corrupted due to some network error. We suggest you to download again. Do you want to download it again?", nil) delegate:self cancelButtonTitle:NSLocalizedString(@"NO", nil) otherButtonTitles:NSLocalizedString(@"YES", nil),nil];
        [corruptVideoAlert show];
        [corruptVideoAlert release];
    }

Answer 1

我发现了类似的问题，我解决了这个问题。试试以下代码：

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playerPlayingErrorNotification:) name:MPMoviePlayerPlaybackDidFinishNotification object:playerViewController.moviePlayer];

 -(void)playerPlayingErrorNotification:(NSNotification*)notif
{

    NSNumber* reason = [[notif userInfo] objectForKey:MPMoviePlayerPlaybackDidFinishReasonUserInfoKey];
    switch ([reason intValue]) {
        case MPMovieFinishReasonPlaybackEnded:
            NSLog(@"Playback Ended");        
            break;
        case MPMovieFinishReasonPlaybackError:
            NSLog(@"Playback Error");
            [self performSelector:@selector(CorruptVideoAlertView) withObject:nil afterDelay:1.0];
            break;
        case MPMovieFinishReasonUserExited:
            NSLog(@"User Exited");
            break;
        default:
            break;
    }
}

接受它，如果它也适合你。祝你今天愉快。

Answer 2

使用

if(moviePlayer.loadState == MPMovieLoadStatePlayable)

并检查它是否可以播放。如果需要，您可以使用MPMoviePlayerLoadStateDidChangeNotification。有关详细信息check apple documentation.

你可以这样试试，

playerViewController = [[MPMoviePlayerViewController alloc]initWithContentURL:url];

player = [playerViewController moviePlayer];
player.movieSourceType = MPMovieSourceTypeFile;
[player prepareToPlay];

playerViewController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
[self presentMoviePlayerViewControllerAnimated:playerViewController];


[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playerInterruptByUser:) name:MPMoviePlayerPlaybackStateDidChangeNotification object:playerViewController.moviePlayer];

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playerFinished:) name:MPMoviePlayerPlaybackDidFinishNotification object:playerViewController.moviePlayer];

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(loadStateChanged:) name:MPMoviePlayerLoadStateDidChangeNotification object:playerViewController.moviePlayer];

    //[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playerFinished:) name:UIApplicationDidEnterBackgroundNotification object:playerViewController.moviePlayer];

在loadStateChanged:方法做以下，

if(player.loadState == MPMovieLoadStatePlayable)
{
 [player play];
}
else
{
    corruptVideoAlert = [[UIAlertView alloc]initWithTitle:NSLocalizedString(@"Corrupt Video", nil) message:NSLocalizedString(@"This video is corrupted due to some network error. We suggest you to download again. Do you want to download it again?", nil) delegate:self cancelButtonTitle:NSLocalizedString(@"NO", nil) otherButtonTitles:NSLocalizedString(@"YES", nil),nil];
    [corruptVideoAlert show];
    [corruptVideoAlert release];
}

Answer 3

对于我的场景，我最终录制了视频的预期内容长度，并确保在您尝试播放视频时文件大小匹配。

从这个意义上说，我决定是否应该播放视频更快。如果文件大小不匹配，我只需重新开始下载。