In which case the general concept would be to put those on the surrounding DIV that houses the player. You may need some sort of id for the player.
Depending on which player you're using how to do it will be different. You'll need to find a way to communicate with the player.
I'd expect that the player is defined on a javascript variable probably. Probably something like
Some sort of unique identifier.
So on the DIV add
onmouseover="xxYourModule_play_hover_video('video_player_h2xkeYNr')" onmouseout="xxYourModule_stop_hover_video()"
Then your functions in your .js file would be
function xxYourModule_play_hover_video(id){
id.play();
}
function xxYourModule_stop_hover_video(){
StopAllPlayers();
}
That's psudo code but hopefully gives you a point in the right direction.