In short, these TVs only play a portion of what your PC and cellphone can play. Keeping in mind all the prior discussions, the solution is to use a better player like a PC or re-encode the video to whatever works on the TV.
I like to use HANDBRAKE but as I've yet to find any common, always works settings I find folk have to try it a few times and sniff it out.
You bring up a great question for Samsung. That is, while they often document what's supported they seem to not tell how to re-encode the video or supply the app to do the work.
Bob
I have a Samsung UN50HU6950F 50" Ultra High Definition smart TV. I bought a 64 gb flash drive, cause trying to use my external 1TB drive had some issues as far as playing back videos. Anyway when I access the video files from the usb via tv port, I get sound but no picture. I updated the tv software to the latest, but still have issues trying to see the picture. The files are mp4 format recorded from a cellphone, and actually I got a couple to play normal but 90% of them don't play. Is there something I'm doing wrong, or like someone said the frame rate may be wrong?. Not sure and need help if someone can guide me in the right direction

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