Finally I figured it out by myself This is the corrected version to do the video for 15 seconds :D CMTime frameTime = CMTimeMake(frameCount*15, [imageArray count]); ...
objective-c,time,compare,equals,cmtime
I found the following way to check by converting it to seconds if(CMTimeGetSeconds(myTime) == CMTimeGetSeconds(kCMTimeZero)) { // do something... } ...