During last week I saw the
Overdrive demo by Titan on the Genesis, and of course I wanted to test it on real hardware. However it is PAL only, and it crashed after a few minutes and displayed a lot of errors while running.
So I ended up modding a Japanese Mega Drive with a 50/60 Hz switch. Having done that, I was curious since I have never had a PAL source before - and because the Overdrive demo was cut in my display due to the change in resolution.
So testing how the Mega Drive version of the suite worked in PAL, and that carried me to investigate it a bit further... so I ended up modifying the suite heavily for PAL use when in that mode.
I don't know if these changes will be useful in general, but they were fun to implement and I ended understanding some finer details. Work has probably not been fully done, but at least 90% has been tested in my setup. Since I don't have a real PAL display, I can only do so much. If anyone is interested in giving me feedback or suggestions on my current build here are the links:
Mega Drive/genesis version 1.12 RC
Mega CD/Sega CD RC 1.12
I mainly added an entry in the menu that states the current resolution and video format, since in PAL it can output 224 or 240 active lines compared to the 224 in NTSC.
- When the console is in PAL, all frames are now counted up to 50, instead of 60... so now time is accurately measured as well. Probably didn't bother anybody too much, but it did bother me once I tested it in PAL.
- You can change between 224 and 240 active lines
- When in fill PAL 240p mode the Grid, linearity, checkerboards, scroll and some other modes are rendered in the full resolution.
- Added a new grid in 256x224 mode for NTSC and PAL, and also a 256x240 in PAL. Since the console supports it and some games do use it, I guessed it might be useful.
I also added a new linearity test when in PAL 240p mode, but I am still in doubt... I would need a proper PAL display in order to test it. It does respect the 59/54 pixel aspect ratio in theory, just as the NTSC one does respect the 10/11 one. If someone could test it, I would be grateful. I will do my best to test it with the EDGE and XRGB machines this weekend though, all other tests were already tested in a real Mega Drive with the scalers. I wonder what the arcade monitors will do when receiving a PAL signal via RGB...