Different FPS Resolution Combos

[estock]

I have a Hero 3+ Black, and currently as I go down in resolution with the video ... the FPS choices get more limited. 720p only lets me choose 60 or 120 fps, what I'm looking for is to encode the smallest video possible ... so ideally 720 or WVGA at 30 or 24 fps. Is this something that is possible through a firmware hack? or is it something that is non negotiable

[KonradIT]

Uh, t app fr_change (if I remember correctly) should do it.