MiSTer FPGA Forum

So I noticed something recently, if I use SNES, PSX, or the older Genesis core and play a game that outputs 480i, it seems to be displayed slightly wrong. It looks like it’s actually being output as 240p or something…

How I can tell is that I use my real Megadrive and play Sonic 2 and look closely at my CRT, I can see the scanlines moving every other frame, like interlaced video should.

But if I play on MiSTer, the scanlines don’t move and are the same as if the console was outputting 240p.

Just wondering if anyone else has this issue. It’s subtle, and you may not have noticed it until this post, but now that I noticed it, it bothers me… I’m using direct video to a PVM

I have the same issue on my PVM 2530 and never been able to figure it out for years. Im glad I'm not the only one with this issue. Anything 480i doesn't look like 480i, its almost like its deinterlacing the image. And I only get this issue with MiSTer.

Open an issue on github under one of the affected cores. Does the newer Megadrive core work correctly? If so, then it is probably per core where the fix needs to be implemented. Also, make sure you are not using the scaler. 480i works for me at least on the PSX core, at least it used to.

thorr wrote: ↑Fri Oct 20, 2023 6:54 pm

Open an issue on github under one of the affected cores. Does the newer Megadrive core work correctly? If so, then it is probably per core where the fix needs to be implemented. Also, make sure you are not using the scaler. 480i works for me at least on the PSX core, at least it used to.

It seems to be every core that outputs interlaced modes I’ve tested. It also happens with the Popeye arcade game and newer Megadrive core.

My theory is that the cores themselves are generating interlaced video correctly but something in the system framework is messing it up before it gets output. I haven’t found anything to confirm that yet though..

rezb1t wrote: ↑Fri Oct 20, 2023 7:55 pm

thorr wrote: ↑Fri Oct 20, 2023 6:54 pm

Open an issue on github under one of the affected cores. Does the newer Megadrive core work correctly? If so, then it is probably per core where the fix needs to be implemented. Also, make sure you are not using the scaler. 480i works for me at least on the PSX core, at least it used to.

It seems to be every core that outputs interlaced modes I’ve tested. It also happens with the Popeye arcade game and newer Megadrive core.

My theory is that the cores themselves are generating interlaced video correctly but something in the system framework is messing it up before it gets output. I haven’t found anything to confirm that yet though..

I will check mine this weekend in the PSX core that I know used to work. Again, if you are using the scaler, it will cause this issue. Not sure without seeing your MiSTer.ini.

I'm using direct_video, I don't have the scaler enabled.

The PSX core displays on my PVM and is perfectly playable. The issue is that it's not actually outputting 480i. This can be seen if you compare it with a non-MiSTer device that outputs 480i and look closely at the scanlines. They 'move' in actual 480i. The MiSTer still looks good but it's not correct. Like BigBossMaeda said, it's like the video is being deinterlaced first, then sent to the CRT as 240p.

I'm using the analog out board with an RGB cable bought from Misteraddons( I have tried 2 different VGA to Scart cables both with same results) , the scaler isn't on and every core that uses 480i is affected.
If I use my real Saturn or PlayStation 480i looks amazing on the PVM, but for some reason MiSTer just won't display it correctly.

Old Genesis core displays the interlaced signal correctly. New MegaDrive core is displaying wrong signal but the last nightly release from yesterday seems to solve the issue. SNES and PSX are OK, otherwhise Saturn and N64 doesn't display interlaced video yet.

using analog io-board with vga to scart cable on 15khz crt.

So I just used the same MiSTer setup with Direct_Video, but sent the signal to an OSSC Pro and it is reporting that the signal is 480i! (or 525i, but same thing)

It looks perfectly fine through the scaler, yet connecting directly to my PVM still looks off. I don't understand what's going on