从iOS中的视频网址或数据获取缩略图 [英] Getting a thumbnail from a video url or data in iOS

问题描述

我正在尝试从iphone 3GS相机拍摄的视频中获取(第一帧的)缩略图，以便进行显示.该怎么做?

I am trying to acquire a thumbnail (of the first frame) from a video taken from iphone 3GS camera so I can display it. How to do this?

推荐答案

此问题的答案是，现在可以在4.0 iOS上使用AVFoundation获取缩略图，下面的代码将类属性url为电影url，诀窍(您可以随时获取缩略图，例如在时间0的示例)

The answer to this question is that one can now with 4.0 iOS get thumbnails using AVFoundation, the following code where the class property url is the movie url, will do the trick (you can get the thumbnail at any time, in the example its at time 0)

-(void)generateImage
{
    AVURLAsset *asset=[[AVURLAsset alloc] initWithURL:self.url 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) {
            NSLog(@"couldn't generate thumbnail, error:%@", error);
        }
        [button setImage:[UIImage imageWithCGImage:im] forState:UIControlStateNormal];
        thumbImg=[[UIImage imageWithCGImage:im] retain];
        [generator release];
    };

    CGSize maxSize = CGSizeMake(320, 180);
    generator.maximumSize = maxSize;
    [generator generateCGImagesAsynchronouslyForTimes:[NSArray arrayWithObject:[NSValue valueWithCMTime:thumbTime]] completionHandler:handler];

}

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