Do Roku devices support 5.1 audio on Prime Video? Yes, they do.
Will Prime work in your country? Only Amazon can answer that question. The providers determine what geographic regions their content is available, and on what devices. However, you have to be careful. Sometimes the content is available in a particular country, but not on Roku devices. Again, that is not something Roku can control. If Amazon says Prime is available in Hungary, I'm sure it is. But it might not be enabled on Roku devices there. The only sure fire way to know for sure is if someone else is already using a Roku there and getting Prime Video.
Dan
Roku Community Streaming Expert
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