When you watch MP4 on PS4, you may ever come across the PS4 MP4 playback issue below.
1. PS4 Can't Read My NTFS USB Drive
Make sure your USB storage devices are in FAT and exFAT formats. PS4 doesn't recognize NTFS which means you can't play videos larger than 4GB. So reduce video size or split videos if need be, meanwhile, you have to convert NTFS to FAT32 or exFAT.
2. PS4 Media Player Not Reading any Files on USB
Create a folder and place all your videos into it when using a USB storage device so that your PS4 system can recognize and read them, otherwise you won't see anything. No specific folder name required for videos, but audio needs to be in a folder named "Music".
3. Can't Play MP4 on PS4
Does PS4 play MP4? Can PS4 play MP4? Definitely, your MP4 can play smoothly if it's the right codec compatible with PS4. If not, you need to transcode to a supported one with PS4 video converter. Then you can play MP4 on PS4.