iOS获取视频中的指定帧的两种方法

方法一 ：AVFoundation

 #import <AVFoundation/AVFoundation.h>

 - (UIImage *)thumbnailImageForVideo:(NSURL *)videoURL atTime:(NSTimeInterval)time {
     AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:videoURL options:nil];
     NSParameterAssert(asset);
     AVAssetImageGenerator *assetImageGenerator =[[AVAssetImageGenerator alloc] initWithAsset:asset];
     assetImageGenerator.appliesPreferredTrackTransform = YES;
     assetImageGenerator.apertureMode =AVAssetImageGeneratorApertureModeEncodedPixels;

     CGImageRef thumbnailImageRef = NULL;
     CFTimeInterval thumbnailImageTime = time;
     NSError *thumbnailImageGenerationError = nil;
     thumbnailImageRef = [assetImageGenerator copyCGImageAtTime:CMTimeMake(thumbnailImageTime, )actualTime:NULL error:&thumbnailImageGenerationError];

     if(!thumbnailImageRef)
         CXIMLog(@"thumbnailImageGenerationError %@",thumbnailImageGenerationError);

     UIImage *thumbnailImage = thumbnailImageRef ? [[UIImage alloc]initWithCGImage:thumbnailImageRef] : nil;
     return thumbnailImage;
 }

方法二：MPMoviePlayerController

 #import <MediaPlayer/MediaPlayer.h>

 MPMoviePlayerController *moviePlayer = [[MPMoviePlayerController alloc] initWithContentURL:videoURL];
 moviePlayer.shouldAutoplay = NO;
 UIImage *thumbnailImage = [moviePlayer thumbnailImageAtTime:time timeOption:MPMovieTimeOptionNearestKeyFrame];