I changed my TV to Insignia TV/DVD combo because it works on 12 volts, no need for inverter, but it won’t play video off USB connection only pictures. My Samsung TV at home can play MP4 videos from USB but not all, you see, MP4 is a container format and may contain different audio and video codec which may not be supported by the TV, so it’s a hit or miss unless you convert the video yourself.
There are inexpensive standalone Digital Media Player that hooks into your existing TV via AV cable which enables you to play digital medias from USB stick/ portable hard drives. Look it up on Amazon: digital media player for USB drives.