iPhone：如何获得从图书馆select的video的持续时间？
我正在使用UIImagePickerController从库中selectvideo文件。 用户可以上传video。
此外，我正在使用videoMaximumDuration属性，而用户想要捕捉video并上传它。
我想知道如何获得选定的video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video。
我能够通过此代码获得有关所选video的一些基本信息：
- (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); }
但所选video的时长没有任何关系。
谢谢…
得到的解决scheme：我使用AVPlayerItem类和AVFoundation和CoreMedia框架。
#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); }
使用AVPlayerItem这个问题的其他答案不适合我，但是这使用AVURLAsset：
#import <AVFoundation/AVFoundation.h> -(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info { NSURL *videoURL=[info objectForKey:@"UIImagePickerControllerMediaURL"]; AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:videoURL options:nil]; NSTimeInterval durationInSeconds = 0.0; if (asset) durationInSeconds = CMTimeGetSeconds(asset.duration); }
迅速
无论使用didFinishPickingMediaWithInfo还是didFinishRecordingToOutputFileAtURL您都可以：
// needed only for didFinishPickingMediaWithInfo let outputFileURL = info[UIImagePickerControllerMediaURL] as! NSURL // get the asset let asset = AVURLAsset(URL: outputFileURL) // get the time in seconds let durationInSeconds = asset.duration.seconds
如果您使用AVFoundation和AVFoundation框架，您可以枚举所有资产，为video应用filter，并使用方法- (id)valueForProperty:(NSString *)property获取每个video的持续时间。 传递属性的ALAssetPropertyDuration 。 下面的代码在控制台上打印出以下内容。
video剪辑编号0是66.80833333333334秒
video剪辑编号1是190.06秒
video剪辑编号2是13.74秒
- (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view. if (!assetItems) { assetItems = [[NSMutableArray alloc] init]; } else { [assetItems removeAllObjects]; } if (!assetLibrary) { assetLibrary = [[ALAssetsLibrary alloc] init]; } ALAssetsLibraryGroupsEnumerationResultsBlock listBlock = ^(ALAssetsGroup *group, BOOL *stop) { if (group) { [group setAssetsFilter:[ALAssetsFilter allVideos]]; [group enumerateAssetsUsingBlock:^(ALAsset *result, NSUInteger index, BOOL *stop) { if (result) { [assetItems addObject:result]; NSString *duration = [result valueForProperty:ALAssetPropertyDuration]; NSLog(@"video clip number %d is %@ seconds\n",index, duration); } }]; } }; ALAssetsLibraryAccessFailureBlock failBlock = ^(NSError *error) { // error handler block NSString *errorTitle = [error localizedDescription]; NSString *errorMessage = [error localizedRecoverySuggestion]; NSLog(@"%@...\n %@\n",errorTitle,errorMessage); }; [assetLibrary enumerateGroupsWithTypes:ALAssetsGroupAll usingBlock:listBlock failureBlock:failBlock]; }
Swift 3.0和Swift 4
let outputFileURL = info[UIImagePickerControllerMediaURL] as! URL // get the asset let asset = AVURLAsset.init(url: outputFileURL) // AVURLAsset.init(url: outputFileURL as URL) in swift 3 // get the time in seconds let durationInSeconds = asset.duration.seconds print("==== Duration is ",durationInSeconds)
是的，您可以使用由MPMediaPlayerController定义的属性“持续时间”。 请尝试一下并检查输出。 你可以参考这里持续时间的属性
尝试使用MPMediaPlayerController播放video，然后使用属性“duration”。 U将能够清楚地了解video的持续时间。