Unity 5 mobile video stops after a second using Handheld.PlayFullScreenMovie()

Hello everyone! im currently developing a game (android) in unity 5 for our school requirement. and i want to add a video at the beginning of the game (something like a splash screen). i use the Handheld.PlayFullScreenMovie() to play the video and it worked, the video is playing but it stops after 1 second or so. it proceeds to another scene without finishing the video. here's what i did with the script

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.SceneManagement;
 public class splashscreenvid : MonoBehaviour {
 private string movie = "splashvid.mp4";
 private int sceneNumber = 1;

    void Start () {
     StartCoroutine(streamVideo(movie));
 }

 private IEnumerator streamVideo(string video)
 {
     Handheld.PlayFullScreenMovie(video, Color.black, FullScreenMovieControlMode.Hidden, FullScreenMovieScalingMode.AspectFill);
     yield return new WaitForEndOfFrame();
     SceneManager.LoadScene(sceneNumber);
 }
 }

someone help me please. thanks!