iOS获取视频的第一帧图片

- (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, 60)actualTime:NULL error:&thumbnailImageGenerationError];

if(!thumbnailImageRef)

NSLog(@"thumbnailImageGenerationError %@",thumbnailImageGenerationError);

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

return thumbnailImage;

}