Is sadly well discussed. In short, yes we can go back to the manual and talk about encoding but let's sum it all up to something simple like "encode content in what works." I think some want longer answers and while I'm pretty good at transcoding I do not have access to all models to see what works.
Let me share that I use HANDBRAKE and Virtual Dub for such work.
I have a new UN40D6420UF connected successfully in my wireless home network. Via AllShare on the TV, I can see all my media files. When selecting a picture (for example) I get the message 'format not compatible'. Why? On the PC side within Allshare, I am unable to add a playlist of any kind. I was able to add a Library which took 3 hours + of "updating" . What is going on? Allshare set up proceeded normally per the instructions with no problem. Thanks for any help anyone can provide.