MovieTexture.isPlaying == false when wait for stream?

i'm streaming a ogg movie from a server, I want to know when the video finishes, so I do:

Code (csharp):

1.  
2. function Update ()
3. {
4.     if (!movieTexture.isPlaying)
5.         Debug.Log("movie end");
6. }
7.  

does isPlaying returns false if the stream is not enough ? or can I trust this method to verify if the video reach the end ?

thanks
am