iPhone：如何从图书馆中选择视频的持续时间？ [英] iPhone :How to get duration of video selected from library?

问题描述

我正在使用 UIImagePickerController 从库中选择视频文件。用户可以上传视频。

I am using UIImagePickerController to choose video file from library. And user can upload the video.

我也在使用 videoMaximumDuration 属性，而用户想要捕获视频并上传。

Also I am using videoMaximumDuration property while user wants to capture video and upload it.

我想知道如何获得所选视频文件的持续时间？这样我就可以限制用户上传持续时间超过20秒的视频。

I want to know that How can I get the duration of selected video file ? so that I can restrict the user to upload video that has duration more then 20 seconds.

我可以通过以下代码获得有关所选视频的一些基本信息：

I am able to get some basic info about selected video by this code :

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    selectedVideoUrl = [info objectForKey:UIImagePickerControllerMediaURL];
    NSError *error;
    NSDictionary * properties = [[NSFileManager defaultManager] attributesOfItemAtPath:selectedVideoUrl.path error:&error];
    NSNumber * size = [properties objectForKey: NSFileSize];
    NSLog(@"Vide info :- %@",properties);
}

但没有关于所选视频的持续时间。

But there is nothing about duration of selected video.

谢谢...

推荐答案

得到解决方案：我用 AVPlayerItem class和 AVFoundation 和 CoreMedia 框架。

Got the solution : I use AVPlayerItem class and AVFoundation and CoreMedia framework.

#import <AVFoundation/AVFoundation.h>
#import <AVFoundation/AVAsset.h>

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    selectedVideoUrl = [info objectForKey:UIImagePickerControllerMediaURL];

    AVPlayerItem *playerItem = [AVPlayerItem playerItemWithURL:selectedVideoUrl];

    CMTime duration = playerItem.duration;
    float seconds = CMTimeGetSeconds(duration);
    NSLog(@"duration: %.2f", seconds);
}

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