Forgive me, it was a Monday morning when we reshot this. I think the final cart was the original PRGROM + MMC3 / 32 CHRROM banks, so it was probably more like 270k total. The video playback I was commenting on entirely fit into the 256K. In my cursory understanding of the MMC3, I think that's the limit that still fits into a normal mapper 4 and will run on device - I know you can up the PRGROM (add PRGRAM), but that would kill our direct cart --> PPU path for the fast playback.
As for the processor, we were definitely pushing the limit with the design we were coding - we had to back off from glitching quite a bit due to busting the number of cycles we had before PPU. I'm sure we could do better with what we know now, or a lot more assembly tuning, but there was the hard limits on being ready by hackday!
did you consider using the hidden expansion port to do your networking (and potentially video decoding)? this would have made the cart free to do a lot more (like subtitle etc)
Forgive me, it was a Monday morning when we reshot this. I think the final cart was the original PRGROM + MMC3 / 32 CHRROM banks, so it was probably more like 270k total. The video playback I was commenting on entirely fit into the 256K. In my cursory understanding of the MMC3, I think that's the limit that still fits into a normal mapper 4 and will run on device - I know you can up the PRGROM (add PRGRAM), but that would kill our direct cart --> PPU path for the fast playback.
As for the processor, we were definitely pushing the limit with the design we were coding - we had to back off from glitching quite a bit due to busting the number of cycles we had before PPU. I'm sure we could do better with what we know now, or a lot more assembly tuning, but there was the hard limits on being ready by hackday!