Life is tough sometimes, pr1.1 just ignored the dropped frames, pr1.2 will stop playing as it notices that it cannot play without frame drops. Its a improvement feature of the media player, which cannot be downgraded (well yes with inception exploit you can install pr1.1 media player, but that cannot be done without exploits). If you don't want to re-encode, then you will not be able to play it on N9, live with it.