Neither. The first is wrong because "countrie's" is completely incorrect, the construction is incorrect and you used a question mark at the end of a statement. The second should be:
"I don't know which country this video was from."
It's not a question so you don't need a question mark at the end and you shouldn't have reversed the subject-verb order.
Which country was this video from? (Question)
I don't know which country this video was from. (Statement)
Student or Learner