如何从 iOS 9 和 Objective C 中的 .MOV 文件中获取缩略图？答案

【问题标题】：How to get the thumbnail from .MOV file in iOS 9 and Objective C?如何从 iOS 9 和 Objective C 中的 .MOV 文件中获取缩略图？
【发布时间】：2016-07-24 17:51:12
【问题描述】：

选择或拍摄视频后，我想在下面的同伴代表旁边使用该视频的缩略图更新我的UIUImageView。我如何使用PHAsset for iOS 9 和Objective C 来做到这一点？

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info 
{
  NSString *mediaType = [info objectForKey: UIImagePickerControllerMediaType];
  if (CFStringCompare ((__bridge CFStringRef) mediaType, kUTTypeMovie, 0) == kCFCompareEqualTo) {
    NSURL *videoUrl=(NSURL*)[info objectForKey:UIImagePickerControllerMediaURL];
    NSData *videoData = [NSData dataWithContentsOfURL:videoUrl];
  }
}

【问题讨论】：

标签： objective-c ios9 uiimagepickercontroller phasset

【解决方案1】：

尝试使用下面的代码，其中asset 参数是您的PHAsset 实例：

PHImageManager *manager = [PHImageManager defaultManager];

[manager requestImageForAsset: asset
                   targetSize: CGSizeMake(100.0, 100.0) // use required size
                  contentMode: PHImageContentModeAspectFill
                      options: nil
                resultHandler: ^(UIImage * _Nullable anImage, NSDictionary * _Nullable info) {

                    dispatch_async(dispatch_get_main_queue(), ^{
                        yourImageView.image = anImage;
                    });
 }];

【讨论】：

【解决方案2】：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

  self.sourceURLString =[NSString stringWithFormat:@"%@", [info                                                         objectForKey:UIImagePickerControllerMediaURL]];

  dispatch_async(dispatch_get_main_queue(), ^{
    self.thumbImageView.image = [self generateThumbImage:self.sourceURLString];
    self.addVideoButton.hidden = YES;
   });

}

-(UIImage *)generateThumbImage : (NSString *)sourceURLString{
  NSURL *sourceMovieURL = [NSURL URLWithString:sourceURLString];
  AVURLAsset *sourceAsset = [AVURLAsset URLAssetWithURL:sourceMovieURL options:nil];
  AVAssetImageGenerator *generateImg = [[AVAssetImageGenerator alloc] initWithAsset:sourceAsset];
  NSError *error = NULL;
  CMTime time = CMTimeMake(1, 65);
  CGImageRef refImg = [generateImg copyCGImageAtTime:time actualTime:NULL error:&error];
  NSLog(@"error==%@, Refimage==%@", error, refImg);

  return [[UIImage alloc] initWithCGImage:refImg];
}

【讨论】：

如果你使用 PhotoLibrary，那么 -requestImageForAsset 可能是更好的方法。

【解决方案3】：

 + (UIImage *)imageFromMovie:(NSURL *)movieURL atTime:(NSTimeInterval)time {
  // set up the movie player
MPMoviePlayerController *mp = [[MPMoviePlayerController alloc] 
initWithContentURL:movieURL];
mp.shouldAutoplay = NO;
mp.initialPlaybackTime = time;
mp.currentPlaybackTime = time;
// get the thumbnail
UIImage *thumbnail = [mp thumbnailImageAtTime:time 
                       timeOption:MPMovieTimeOptionNearestKeyFrame];
// clean up the movie player
[mp stop];
[mp release];
return(thumbnail);

}

【讨论】：

MPMoviePlayerController 在 iOS 8 中已弃用