I am planning to visit a relative that has an ATV-4K and plan to bring wedding videos for everyone to view. What file formats can the ATV play from a SAMBA share? If you have had success please state this in your reply: thank you
You'll need to install a third-party app like VLC or Plex to play off a Samba/SMB share. I believe VLC can read directly off a Samba share, but Plex might need you to mount the share on a computer and install Plex Server on that computer.
You can then play just about any modern video file thru those apps.
If you are limited to the built-in apps, you'll need to put your movies in MP4 format, with an AAC audio track as the first track (AC-3 surround sound can be included after the AAC track). (I might be wrong about this for ATV 4K, maybe it supports other formats than the previous 2 ATV's.) Then, you'll still need a computer running iTunes, load your videos into iTunes, then turn on Home Sharing in iTunes and on the ATV.