如何获得avurlasset目标的创建日期和时间?

Question

我有一个应用程序，我从一个照片库中挑选一个视频，我想从它的元数据中获得它被创建的日期和时间(如果可能的话，它被拍摄的位置)，这样我就可以用它来做一些标签。我可以对从图片库中挑选的图像这样做，但它不适用于视频。这是我的图片，但我似乎不能适应一个视频。

所以我做了一些调整，像这样:

//我从照片库中获取视频

if (picker.sourceType ==UIImagePickerControllerSourceTypePhotoLibrary) {
NSLog(@"info:%@",info);
NSURL * movieURL = [info valueForKey:UIImagePickerControllerMediaURL] ;
NSData * movieData = [NSData dataWithContentsOfURL:movieURL];

//我将它保存到documentsDirectory中，并在中间点获得图像

NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [documentPaths objectAtIndex:0];
NSString *slash = [documentsDirectory stringByAppendingPathComponent:@"/"];
NSString *documentsDirectory2 = [slash stringByAppendingPathComponent:self.user.text];
NSString *documentsDirectory21 = [documentsDirectory2 stringByAppendingPathComponent:@"/Movie"];
if (![[NSFileManager defaultManager] fileExistsAtPath:documentsDirectory21])
[[NSFileManager defaultManager] createDirectoryAtPath:documentsDirectory21 withIntermediateDirectories:NO attributes:nil error:&error];
NSString *fullPath = [documentsDirectory21 stringByAppendingPathComponent:[[self imageNameTextField]text]];
fullPath = [fullPath stringByAppendingFormat:@".mp4"];
[ movieData writeToFile:fullPath atomically:YES];


AVURLAsset *anAsset = [[AVURLAsset alloc] initWithURL:movieURL options:nil];

//这是我修改的

PHAsset *theAsset = [info valueForKey:UIImagePickerControllerMediaURL] ;

NSLog(@"creationDate1:%@",theAsset);
NSLog(@"creationDate2:%@",anAsset.creationDate.value);

NSDate *creationDate =(NSDate *)anAsset.creationDate.value;
NSDateFormatter *dateFormatter=[[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"MMMM-dd-yyyy"];
dayString = [dateFormatter stringFromDate:creationDate];
NSDateFormatter *dateFormatter2=[[NSDateFormatter alloc] init];
[dateFormatter2 setDateFormat:@"hh:mm a"];
timeString = [dateFormatter2 stringFromDate:creationDate];
if ([[anAsset tracksWithMediaType:AVMediaTypeVideo] count] > 0) {

AVAssetImageGenerator *imageGenerator =
[AVAssetImageGenerator assetImageGeneratorWithAsset:anAsset];
Float64 durationSeconds = CMTimeGetSeconds([anAsset duration]);

CMTime midpoint = CMTimeMakeWithSeconds(durationSeconds/2.0, 600);
NSError *error;
CMTime actualTime;

CGImageRef halfWayImage = [imageGenerator copyCGImageAtTime:midpoint actualTime:&actualTime error:&error];

if (halfWayImage != NULL) {

NSString *actualTimeString = (NSString *)CFBridgingRelease(CMTimeCopyDescription(NULL, actualTime));
NSString *requestedTimeString = (NSString *)CFBridgingRelease(CMTimeCopyDescription(NULL, midpoint));
NSLog(@"Got halfWayImage: Asked for %@, got %@", requestedTimeString, actualTimeString);

myImage.image = [UIImage imageWithCGImage:halfWayImage scale:1.0 orientation:UIImageOrientationRight];
// Do something interesting with the image.
CGImageRelease(halfWayImage);

}
}

在我丢弃之前这里有什么

Answer 1

我终于想通了。将以下代码放在

后面AVURLAsset *anAsset = [[AVURLAsset alloc] initWithURL:movieURL options:nil];

PHAsset *theAsset = [info valueForKey:UIImagePickerControllerMediaURL];

NSLog(@"creationDate1:%@",theAsset);
NSLog(@"creationDate2:%@",anAsset.creationDate.value);
NSDate *creationDate =(NSDate *)anAsset.creationDate.value;
NSDateFormatter *dateFormatter=[[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"MMMM-dd-yyyy"];
dayString = [dateFormatter stringFromDate:creationDate];
NSDateFormatter *dateFormatter2=[[NSDateFormatter alloc] init];
[dateFormatter2 setDateFormat:@"hh:mm a"];
timeString = [dateFormatter2 stringFromDate:creationDate];

我已经修改了我原来的帖子来反映这些变化。现在，如果我能从资产中获得位置的元数据，我就万事通了。