I think I found a workaround 
- First of all I create an object video using Hype preset
- Gives an unique ID to the video object
- transform it as a persistant symbol and copy it on all the scenes I need it
- Create a function to replace the source attribut of the video object on scene load.
It seams to work on iPad and iPhone …
here is the code :
var video = hypeDocument.getElementById("film");
//get scene name
var scenename = hypeDocument.currentSceneName();
var filmname = "...";
switch (scenename)
{
case "01":
filmname="Video65.mp4";
break;
case "02":
filmname="Video70.mp4";
break;
case "03":
filmname="Video73.mp4";
break;
case "16":
filmname="Video76.mp4";
break;
case "17":
filmname="Video70.mp4";
break;
}
video.src='${resourcesFolderName}/' + filmname;
video.play();