self.player.currentItem.asset.duration

#import <AVFoundation/AVPlayer.h>
#import <AVFoundation/AVPlayerItem.h>
#import <AVFoundation/AVAsset.h>

CMTime duration = self.player.currentItem.asset.duration;
float seconds = CMTimeGetSeconds(duration);
NSLog(@"duration: %.2f", seconds);

AVFoundation
CoreMedia

self.player.currentItem.duration;

if let duration = player.currentItem?.asset.duration {
    let seconds = CMTimeGetSeconds(duration)
    print(seconds)
}

- (CMTime)playerItemDuration
{
    AVPlayerItem *thePlayerItem = [player currentItem];
    if (thePlayerItem.status == AVPlayerItemStatusReadyToPlay)
    {
        /*
         NOTE:
         Because of the dynamic nature of HTTP Live Streaming Media, the best practice
         for obtaining the duration of an AVPlayerItem object has changed in iOS 4.3.
         Prior to iOS 4.3, you would obtain the duration of a player item by fetching
         the value of the duration property of its associated AVAsset object. However,
         note that for HTTP Live Streaming Media the duration of a player item during
         any particular playback session may differ from the duration of its asset. For
         this reason a new key-value observable duration property has been defined on
         AVPlayerItem.

         See the AV Foundation Release Notes for iOS 4.3 for more information.
         */

        return([playerItem duration]);
    }

    return(kCMTimeInvalid);
}

float scrubberBarLocation = (scrubberBgImageView.frame.size.width / 100.0f) * [self moviePercentage];


- (float)moviePercentage {

    CMTime t1 = [avPlayer currentTime];
    CMTime t2 = avPlayer.currentItem.asset.duration;

    float myCurrentTime = CMTimeGetSeconds(t1);
    float myDuration = CMTimeGetSeconds(t2);

    float percent = (myCurrentTime / myDuration)*100.0f;
    return percent;

}

- (void)updateVideoPercent:(float)thisPercent {

    CMTime t2 = avPlayer.currentItem.asset.duration;
    float myDuration = CMTimeGetSeconds(t2);

    float result = myDuration * thisPercent /100.0f;

    //NSLog(@"this result = %f",result); // debug

    CMTime seekTime = CMTimeMake(result, 1);

    [avPlayer seekToTime:seekTime];

}