.m

- (void)panningBegan
{
    if (self.playerViewAnimator.isRunning)
    {
        return;
    }

    CGRect targetFrame;

    switch (self.playerState) {
        case PlayerStateThumbnail:
            self.originalPlayerViewFrame = self.playerView.frame;
            targetFrame = self.view.frame;
            break;
        case PlayerStateFullscreen:
            targetFrame = self.originalPlayerViewFrame;
    }

    self.playerViewAnimator = [[UIViewPropertyAnimator alloc] initWithDuration:0.5 dampingRatio:0.8 animations:^{
        self.playerView.frame = targetFrame;
    }];
}