iosobjective-cavplayeralassetslibrarycmtime

How to get thumbnail image of video from ALAsset in iOS?


I want to get thumbnail images of every frame from video and then save this images in Mutable Array of images.

I want to use this images to play as a animation.

NSURL* assetURL = [self.asset valueForProperty:ALAssetPropertyAssetURL];
NSDictionary* assetOptions = nil;

AVAsset* myAsset = [[AVURLAsset alloc] initWithURL:assetURL options:assetOptions];

self.imageGenerator = [AVAssetImageGenerator assetImageGeneratorWithAsset:myAsset];


int duration = CMTimeGetSeconds([myAsset duration]);

for(int i = 0; i<duration; i++)
{
    CGImageRef imgRef = [self.imageGenerator copyCGImageAtTime:CMTimeMake(i, duration) actualTime:NULL error:nil];
    UIImage* thumbnail = [[UIImage alloc] initWithCGImage:imgRef scale:UIViewContentModeScaleAspectFit orientation:UIImageOrientationUp];
    [thumbnailImages addObject:thumbnail];
}

I am using above code to get thumbnail images but the problem is if there is a 2 seconds video i am only getting 2 thumbnails but i want 20 thumbnails (10 thumbnail per second).

So, how to use CMTimeMake to get thumbnails for every .1 second


Solution

  • Code form reference site : Thumbnail image from Video

    Objective - C

    -(UIImage *)generateThumbImage : (NSString *)filepath
    {
        NSURL *url = [NSURL fileURLWithPath:filepath];
    
        AVAsset *asset = [AVAsset assetWithURL:url];
        AVAssetImageGenerator *imageGenerator = [[AVAssetImageGenerator alloc]initWithAsset:asset];
    self.imageGenerator.appliesPreferredTrackTransform = YES; 
            CMTime time = [asset duration];
            time.value = 0;
            Float duration = CMTimeGetSeconds([myAsset duration]);
       for(Float i = 0.0; i<duration; i=i+0.1)
        {
         CGImageRef imgRef = [self.imageGenerator copyCGImageAtTime:CMTimeMake(i, duration) actualTime:NULL error:nil];
         UIImage* thumbnail = [[UIImage alloc] initWithCGImage:imgRef scale:UIViewContentModeScaleAspectFit orientation:UIImageOrientationUp];
        [thumbnailImages addObject:thumbnail];
        }
    }
    

    Swift

    func generateThumbImage(url : NSURL) -> UIImage{
            var asset : AVAsset = AVAsset.assetWithURL(url) as! AVAsset
            var assetImgGenerate : AVAssetImageGenerator = AVAssetImageGenerator(asset: asset)
            assetImgGenerate.appliesPreferredTrackTransform = true
            var error       : NSError? = nil
            var time        : CMTime = CMTimeMake(1, 30)
            var img         : CGImageRef = assetImgGenerate.copyCGImageAtTime(time, actualTime: nil, error: &error)
            var frameImg    : UIImage = UIImage(CGImage: img)!
    
            return frameImg
        }