Find the end of the movietexture

Hi, I'm trying to switch the level after the movie played.

I have tried the method in the

http://answers.unity3d.com/questions/202303/on-movie-end.html#answer-1000687

public class movie : MonoBehaviour {

 public MovieTexture movie;
 private AudioSource aud;
 private Renderer r;
 public Action cb;


 // Use this for initialization
 void Start () {
     r = GetComponent<Renderer> ();
     movie.loop = false;
     r.material.mainTexture = movie as MovieTexture;
     aud = GetComponent<AudioSource>();
     aud.clip = movie.audioClip;
     cb = Test;
 }

 // Update is called once per frame
 void Update () {
             movie.Play();
             aud.Play();        
             // Wait for the clip to finish
     StartCoroutine (FindEnd (cb));
 }

     
 private IEnumerator FindEnd(Action Callback)
 {
     while (movie.isPlaying) {
         yield return 0;

     }
     Callback ();
     yield break;
 }

 private static void Test()
 {
     Debug.Log("WORKS");
 }

}

But the code is stucked in the while playing loop and never get out. I have to finish the movie demo in 2 days but I have spent too long on this issue. Can someone help? Thank you so much