My HDTV has 1080i what does this mean?

Killzone 3 on a 720p(?) HDTV, PLEASE HELP!?

• When i play Killzone 3 i set my display to 720p, but when i turn on the game and get to the menu the picture is bulged out in the center, and the vertical lines are not straight, like it would look on a CRT TV that has the bulged out screen even though i am playing on a flatscreen hdtv. How do i fix this i've tried just 720p, 720+1080i, 720p+1080i+1080p but it still does it. PLEASE HELP BQ: I read online that the type of TV i had is 720p but my PS3 automatically sets it to 1080p, does this mean that my TV is 1080p?

• Answer:

  what's the make of the tv, because mine does it automatically if the game is 720 the tv settings automatically adjusts it self to 720 on the ps3 scan for the best hd settings for the tv...