tiobilyy - the link you provided in your second post is an excellent choice, I assure you. I already have it and it's a great rockchip player with an external speaker and fast interface. Here are pictures:
Even though it's only 512mb, you can always buy mini sd cards and expand the memory. But I'm warning you, the shipping takes FOREVER. It took a month for the player to get to me. Good luck in your choice with an mp4!