Plays lots of files but the mp4 is only a container so depends on what codecs are used. Does not play everything. Quite fussy about external hard drives, have to be in FAT32 so file sizes are limited, would not play my 1TB hard drive, maybe too many files in the root but not tested fully, I use it mostly with 16GB sandisk cruzer pendrive which it reads no problem. This is not HD only upscales to HD only reads SD files. Hope this helps.

This certainly plays dvd .iso files with menu support.