How to Count Video playing remaining Time in iOS?

Question

 [[NSNotificationCenter defaultCenter] addObserver:self
                                                     selector:@selector(MPMoviePlayerLoadStateDidChange:)
                                                         name:MPMoviePlayerLoadStateDidChangeNotification object:mPlayer.moviePlayer];


 - (void)MPMoviePlayerLoadStateDidChange:(NSNotification *)notification
        {
            if ((mPlayer.moviePlayer.loadState & MPMovieLoadStatePlaythroughOK) == MPMovieLoadStatePlaythroughOK)
            {
                NSLog(@"content play length is %g seconds", mPlayer.moviePlayer.duration);
                timeRemain = [NSTimeIntervalSince1970 [mPlayer.moviePlayer.duration]-[mPlayer.moviePlayer.currentPlaybackTime]];
                NSLog(@"Time Remaining::%g",timeRemain);
            }
        }

Answer 1

MPMoviePlayerController duration is in seconds already. So

[mPlayer.moviePlayer.duration]-[mPlayer.moviePlayer.currentPlaybackTime]

will return the number of seconds in current time and total duration as NSTimeInterval.

Answer 2

-(void)updateDuration
{
    int remainingDuration = mPlayer.moviePlayer.duration - mPlayer.moviePlayer.currentPlaybackTime;

    if (mPlayer.moviePlayer.currentPlaybackTime != mPlayer.moviePlayer.duration  ) {

        [btnRemainingDuration setTitle:[NSString stringWithFormat:@"Video ends in %d seconds", remainingDuration] forState:UIControlStateNormal];
    }
}