iOS 截取视频缩略图

两种实现方法：

1. avfoundation 实现：

- (UIImage*)getThumbImage:(NSString *)videoPath

{

    AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:[NSURL fileURLWithPath:videoPath] options:nil];

    AVAssetImageGenerator *gen = [[AVAssetImageGenerator alloc] initWithAsset:asset];

    gen.appliesPreferredTrackTransform = YES;

    CMTime time = CMTimeMakeWithSeconds(0.0, 600);

    NSError *error = nil;

    CMTime actualTime;    

    CGImageRef image = [gen copyCGImageAtTime:time actualTime:&actualTime error:&error];

    UIImage *thumb = [[UIImage alloc] initWithCGImage:image];

    CGImageRelease(image);

    [gen release];

    [asset release];

    return [thumb autorelease];

}

2. MPMoviePlayerController 实现：

- (UIImage*)getThumbImage:(NSString *)videoPath

{

    MPMoviePlayerController *player = [[MPMoviePlayerController alloc]initWithContentURL:[NSURL fileURLWithPath:videoPath]];
    UIImage *thumbImage=[player thumbnailImageAtTime:nTime timeOption:MPMovieTimeOptionNearestKeyFrame];
    [player release];

    return thumbImage;

}