In that video AC4 trophies (offline trophies) auto pops when AC4 starts first time on the ps4.
Author says "After completing a large chunk of Assassin's Creed 4: Black Flag, the trophies started pouring in =)."
Ah that's a bonus then! Dunno how it would work unless it's got a cloud save thing, wonder if it'll convert the progress too.
I held put for the ps4 version so I didn't get two trophy sets lol
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