AVPlayer playing just 5 seconds of video, audio ok

I have an AVPlayer object that plays videos perfectly fine. But I am trying to make that player to fade in when the video starts and fade out when it ends.

As soon as I add the code to do this, the videos start to play fine, audio and video and after about 5 seconds the video freezes and the audio continues.

This is the code for the fade in, fade out of one second.

  // duration is the video duration

  CMTime fadeDuration = CMTimeMakeWithSeconds(1.0, duration.timescale);
  CMTime fadeOutStartTime = CMTimeSubtract(duration, fadeDuration);

  CMTimeRange fadeInRange  = CMTimeRangeMake(kCMTimeZero, fadeDuration);
  CMTimeRange fadeOutRange = CMTimeRangeMake(fadeOutStartTime, fadeDuration);

   AVAssetTrack *videoTrack = [[asset tracksWithMediaType:AVMediaTypeVideo] firstObject];;
      AVMutableVideoCompositionLayerInstruction *instructionLayerFadeInOut = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack];

    [instructionLayerFadeInOut setOpacityRampFromStartOpacity:0.0f
                                              toEndOpacity:1.0f
                                                 timeRange:fadeInRange];


    [instructionLayerFadeInOut setOpacityRampFromStartOpacity:1.0f
                                              toEndOpacity:0.0f
                                                 timeRange:fadeOutRange];

    AVMutableVideoCompositionInstruction *fadeInOut = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
    fadeInOut.timeRange = CMTimeRangeMake(kCMTimeZero, duration);
    fadeInOut.layerInstructions = @[instructionLayerFadeInOut];

    AVMutableVideoComposition *videoComposition = [AVMutableVideoComposition videoComposition];
    videoComposition.instructions = @[fadeIn];
    videoComposition.frameDuration = CMTimeMake(1.0, self.frameRate);

    CGSize videoSize = [videoTrack naturalSize];
    videoComposition.renderSize = videoSize;

    [playerItem setVideoComposition:videoComposition];

removing the last line makes the video play fine again.