MPMoviePlayerControlle thumbnailImageAtTime：timeOption：给出空的UIImage

我使用这个来获得video的预览缩略图：

- (void)createThumb { NSInteger paddingLeft = 22; NSInteger paddingTop = 22; CGFloat frameWidth = self.preview.frame.size.width - (2 * paddingLeft); CGFloat frameHeight = self.preview.frame.size.height - (2 * paddingTop); CGSize size = CGSizeMake(frameWidth, frameHeight); MPMoviePlayerController *mp = [[MPMoviePlayerController alloc] initWithContentURL:self.fileUrl]; NSLog(@"File url %@",self.fileUrl); UIImage *thumbnail = [mp thumbnailImageAtTime:0.0 timeOption:MPMovieTimeOptionNearestKeyFrame]; [mp stop]; [mp release]; if (!thumbnail){ thumbnail = [UIImage imageNamed:@"video_dummy"]; } thumb = [[thumbnail gtm_imageByResizingToSize:size preserveAspectRatio:YES trimToFit:NO] retain]; } 

但它不起作用。 由此产生的UIImage总是零。 有人可以帮忙吗？

谢谢，菲利普

Answer 1

好的，我发现一个解决scheme

而不是使用MPMoviePlayerController，我使用它，它做得更好：

  NSInteger paddingLeft = 24; NSInteger paddingTop = 24; CGFloat frameWidth = self.preview.frame.size.width - (2 * paddingLeft); CGFloat frameHeight = self.preview.frame.size.height - (2 * paddingTop); CGSize size = CGSizeMake(frameWidth, frameHeight); AVURLAsset *asset=[[AVURLAsset alloc] initWithURL:self.fileUrl options:nil]; AVAssetImageGenerator *generator = [[AVAssetImageGenerator alloc] initWithAsset:asset]; generator.appliesPreferredTrackTransform=TRUE; [asset release]; CMTime thumbTime = CMTimeMakeWithSeconds(0,30); AVAssetImageGeneratorCompletionHandler handler = ^(CMTime requestedTime, CGImageRef im, CMTime actualTime, AVAssetImageGeneratorResult result, NSError *error){ if (result == AVAssetImageGeneratorSucceeded) { UIImage *thumbnail=[[UIImage imageWithCGImage:im] retain]; thumb = [[thumbnail gtm_imageByResizingToSize:size preserveAspectRatio:YES trimToFit:NO] retain]; NSData *thumbData = UIImageJPEGRepresentation(thumb, 0.2); [thumbData writeToFile: [[[NSFileManager defaultManager] contentDirectory] stringByAppendingPathComponent:self.thumbFilename] atomically: NO]; [generator release]; [self.preview setImage: thumb]; } else { UIImage *thumbnail=[[UIImage imageNamed:@"video_dummy"] retain]; thumb = [[thumbnail gtm_imageByResizingToSize:size preserveAspectRatio:YES trimToFit:NO] retain]; NSData *thumbData = UIImageJPEGRepresentation(thumb, 0.2); [thumbData writeToFile: [[[NSFileManager defaultManager] contentDirectory] stringByAppendingPathComponent:self.thumbFilename] atomically: NO]; [generator release]; [self.preview setImage: thumb]; } }; CGSize maxSize = CGSizeMake(320, 180); generator.maximumSize = maxSize; [generator generateCGImagesAsynchronouslyForTimes:[NSArray arrayWithObject:[NSValue valueWithCMTime:thumbTime]] completionHandler:handler]; 

所以如果你想这样做使用AVFramework方法