This might be what you are looking for;
https://www.ebay.com/itm/Digital-ATS...EAAOSwnVhaOkLx
I have two of these & these were the easiest solution i found so far as to play the classic tv shows that i downloaded from you-tube & other classic tv sites on my vintage tv's. this device plays back mp4 files flawlessly. the tuner part is not that great. it does have a composite A/V output as well as channel 3/4 rf out. best of all, it's cheap. it will play 4.3 content as 4.3 (full screen).