I m so happy can do all so good, but only got a problem; in moments that open my aplication show black screen...  what i can do?

ONE LAST QUESTION, AS MODIFIED AFTER LEAVING TEXT SAYING GO SPLASH IN A GREEN Botton.

Not sure i understand the question...

THANKS SO MUCH ALESSANDRO I CAN, MISTAKE WAS PUT APP MANAGER IN THE HIERARCHY, ONE LAST QUESTION, AS MODIFIED AFTER LEAVING TEXT SAYING GO SPLASH IN A GREEN Botton.

THANK U ONE MORE TIME.

Have you tried what I suggested below ? and it does not work ?

the steps are relatively simple:

- import the VideoPlaybacak untiypackage in a frsh new Unity project

- open the Vuforia scene 

- place your own videos (video files) into the Assets/StreamingAssets folder of your project, next to the existing sample video files

- in the scene, click on an Image target to show its children in the hierarchy

- click on the video object under the image target

- in the inspector panel, change the video filename, so use your own video instead of the sample one

- build and run

:(   i cant,  dont know what do, I m  testing to all ways but nothing.

I am also using Unity 4.3.4 and Vuforia 2.8... just try the VideoPlayback sample of Vuforia 2.8, by replacing the video files with your own files and changing the file path in the Inspector of the video gameobject under each Image target.

If that works, it is already good news;  if it does not work, it could be a problem with the video files for instance..

Have you tried replacing the Video files in the VideoPlayback samples with yours ?

I would suggst trying that (without changing anything in the sample code);

see also this:

https://developer.vuforia.com/forum/faq/videoplayback-what-videos-can-i-play-what-platform