VideoFrameExtract.m

AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:url options:nil];
AVAssetImageGenerator *generator = [[AVAssetImageGenerator alloc] initWithAsset:asset];
generator.requestedTimeToleranceAfter =  kCMTimeZero;
generator.requestedTimeToleranceBefore =  kCMTimeZero;
for (Float64 i = 0; i < CMTimeGetSeconds(asset.duration) *  FPS ; i++){
  @autoreleasepool {
    CMTime time = CMTimeMake(i, FPS);
    NSError *err;
    CMTime actualTime;
    CGImageRef image = [generator copyCGImageAtTime:time actualTime:&actualTime error:&err];
    UIImage *generatedImage = [[UIImage alloc] initWithCGImage:image];
    [self saveImage: generatedImage atTime:actualTime]; // Saves the image on document directory and not memory
    CGImageRelease(image);
  }
}

//=====

-(void) getAllImagesFromVideo
{
   imagesArray = [[NSMutableArray alloc] initWithCapacity:375];
   times = [[NSMutableArray alloc] initWithCapacity:375];

   for (Float64 i = 0; i < 15; i += 0.033) // For 25 fps in 15 sec of Video
   {
       [times addObject:[NSValue valueWithCMTime:CMTimeMakeWithSeconds(i, 60)]];
   } 

   [imageGenerator generateCGImagesAsynchronouslyForTimes:times completionHandler:^(CMTime requestedTime, CGImageRef image, CMTime actualTime, AVAssetImageGeneratorResult result, NSError *error) {
       if (result == AVAssetImageGeneratorSucceeded)
       {
           [imagesArray addObject:[UIImage imageWithCGImage:image]];
           CGImageRelease(image);
       }
   }];
}