From Samsung official website, we clearly know that Samsung TV is only compatible with MP4 in H.264/MPEG-4 AVC video codec and AAC audio codec. However, MP4 is a container format which contains various kinds of video and audio codecs. Once the MP4 files can't meet the requirement of Samsung TV input format, you'll get into trouble to play MP4 in Samsung TV.
To solve this issue, you'd better to convert your MP4 to Samsung TV MP4 format. Highly recommend three methods here:
Method One: HandBreak can convert MP4 to Samsung TV MP4 format.
Method Two: A full tutorial to help you solve various kinds of video that Samsung TV won't play at http://www.idealshare.net/video-convert ... y-mp4.html
Method Three: Online-converter is similer to HandBreak.
Hope one of them fits you.