If your doing a cinematic, you can change the id in the playercreateinfo.
If you want to play a movie (it plays from a file in your WoW folder not move camera around) you have to do a simple C++ script, for example I removed the cinematic from the playercreateinfo then added the following script to play wrathgate on login:
Code:
#include "StdAfx.h"
#include "Setup.h"
void PlayMovieOnFirstLogin(Player * pPlayer)
{
pPlayer->SendTriggerMovie(14);
}
void SetupPlayMovieOnFirstLogin1(ScriptMgr * mgr)
{
mgr->register_hook(SERVER_HOOK_EVENT_ON_FIRST_ENTER_WORLD, PlayMovieOnFirstLogin);
}