SamyGO

A friend just bought a 720p 24" Samsung smart TV for his RV. Funny thing is, it will initially show a thumbnail image from HEVC encoded video in MKV format but when attempting to play them *then* it says it can't and replaces the thumbnail with the NO symbol.

So it CAN read the codec and format as evidenced by displaying the thumbnail but playing has been disabled. Unfortunately he updated to the latest firmware already.

Is there a 3rd party HEVC player for Tizen?

There is still the possibility that compression parameters were set when creating the hevc file, that the TV just does not support.