Fish eye removal ?

Hey guys so I'm digging my gopro silver but I'm having a hard time getting rid of the fish eye in videos. I can do it for photos in photoshop no problem. But I've downloaded so many programs and can't do it to the videos. I even downloaded gopros old studio software that has the option to remove it. But nothing. I thought davinci resolve would do it but it won't on the free edition. Anyone have any free options?