Riva and Overscan

[DisasterIncarna]

While using my emulated amiga setup in FS-UAE or WinUAE i often run my setup using an FPU, my setup is configured in such a way that it runs on anything, emulated or real, so because of that, i wont always have an FPU and my main Video player with an FPU is FFPlay, it can play more than Riva and works perfectly well.

However, with no FPU i launch riva as a substitute, and provided i am playing the files riva supports all is well, but i have noticed that riva is playing back the videos on a max overscan rather than normal, so on my emulated setup at least theres a large chunk of the video being played offscreen, i'm not sure about RTG but this behavior is when im specifically running an 020/NoFPU/AGA config.

Does anyone know how to stop riva from using max overscan mode? i tried using ModePro, but as riva is playing back its video using AGA/HAM screenmodes, i cant modepromote those as HAM/HAM AGA isnt a thing it supports, or at least all my attempts so far have produced nothing but a screen of corrupted gfx so i'm a little stuck.

Any ideas?