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Saturn Screenshots (interlaced and hi-res games)

sibor - Jul 2, 2023

		sibor		Jul 2, 2023
			Hi, I would like to know how to take accurate screenshots for some interlaced Saturn games (I use Beetle Saturn and SSF): Virtua Fighter 2, DOA, Fighters Megamix... Beetle Saturn take screenshots with interlacing artifacts, we can use a Bob deinterlacing shader with retroarch but I wonder if it's enough in this case, I have a doubt because IIRC there is full frame and half frame interlacing types (I guess these full frame and half frame are for framebuffer if I understood correctly) and apparently Bob deinterlacing is only sufficient for Full frame interlacing because in case of half frame there would be more artifacts and "shaking"), SSF on the other hand does either takes none interlaced screenshots or it automatically deinterlace them (I don't know since I can't find any information) but since it doubles the resolution for all games I assume that the screenshots are correct for Virtua Fighter 2 and DOA but for Fighters Megamix I doubt it because normally only the backgrounds are in high resolution but not the 3D models so I think they are upscaled with SSF (it seems to be the case given their over-pixelation), so does anyone know the best way to take these screenshots correctly? Thanks

		dibz		Jul 3, 2023
			I guess I'm not entirely sure what your goal is here and what you mean by accurate? Seems to me entirely disabling deinterlacing -- assuming you can -- and capturing that would be the most "accurate". It sounds like SSF probably deinterlaces by doubling the fields, which is a nicer way to do it. Also, what makes you think something-or-other is over-pixelated? Saturn stuff always looks pixelated, so to speak.

		nando		Jul 3, 2023
			Fighters Megamix runs in interlaced mode? are you sure about that? it's not running in high-res, because it uses lighting effects. you can definitely see the interlacing in the Saturn high-res mode, even on a CRT, but not in the other resolutions.

		sibor		Jul 3, 2023
			dibz said: by "accurate" I mean correct resolution or even pixel-perfect and without interlacing artifacts if possible. yeah, entirely "disabling" interlacing but not really in the sense of "disabling" it, more in the sense of whether it was possible for an emulator like SSF to directly display frames from the framebuffer or something, assuming that they are not interlaced but come out interlaced (as is sometimes the case on PS2 for certain interlaced games and for which there are no-interlacing patches which allow the non-interlaced frames to be displayed directly). as for over-pixelation I was thinking of the characters from Fighters Megamix since the backgrounds are in hi-res but not the characters so I thought that if the SSF doubles the resolution it can affect the pixelation of the characters but not of the backgrounds which are already in hi-res (knowing that SSF doubles the resolution for all games even those which are neither interlaced nor in hi-res like Burning Rangers or DBZ Shin Butouden for example)

		sibor		Jul 3, 2023
			nando said: according to Bettle Saturn it is interlaced, for hi-res I don't know but i guess it's the case for the frames at the output (but not necessarily for the internal resolution) since the backgrounds are in hi-res and the interlaced screenshots taken with Beetle Saturn are in 704x480 (while for other low-res games the screenshots are in 352x240, 320x240 etc), that's why I wonder if there are games like this whose frames are not interlaced in the framebuffer but only at the output (unfortunately I don't know much about the hardware of the Saturn), there is also the fact that SSF displays the resolution in the window info and for hi-res interlaced games it does not displays 704x4xx but rather 352x2xx, which make me think there may be a difference between internal resolution and output resolution for these interlaced hi-res modes.

		Danthrax		Jul 6, 2023
			In Fighting Vipers and Fighters Megamix, doesn't VDP1 render the characters (and walls) in a lower resolution than the VDP2 background planes? So you're seeing, in a way, two different resolutions at once? I thought I read that somewhere.

		sibor		Jul 7, 2023
			yes, here is a GIF that shows it well (taken with SSF), the 1st screenshot is at the output resolution (704x448) and the 2nd screenshot has been downscaled to 352x224 in nearest neighbor : as you can see the characters remain exactly the same while the background and UI clearly drop in resolution, which shows that the characters are low res and upscaled while the backgrounds are hi-res, maybe the interlacing is helping to smooth out the characters or something while keeping the high resolution of the backgrounds, because on real hardware videos with good upscalers there is not an over-pixelation like that on the characters, in any case I think the best way to take screenshots of these games remains to capture in interlaced and in lossless then to deinterlace the video with the best deinterlacers (always in lossless) and finally to take the screenshots, unfortunately retroarch does not record interlaced videos and there does not seem to be a better solution like capturing non-interlaced frames from framebuffers or something.

		Danthrax		Jul 7, 2023
			sibor said: That's awesome. Great gif.

		nando		Jul 7, 2023
			yeah, that makes a lot of sense now. I loved FMM, it's too bad I haven't played it really since its original release. It's obvious from your GIF that the characters run in a normal resolution, but I didn't realize the backgrounds were in high-res mode (and the UI, which must also be rendered by VPD2 based on your GIF). IMO, due to the better lighting effects, this game was more impressive than VF2 - even with lower resolution rendering of the characters. I especially liked the lighting effects on the desert background. If only XL2 was around back then to give Dural real-time reflection maps... As to your original question, it could be that getting an accurate screenshot of a mixed high-res and standard res mode from an emulator won't work, because it's not real-hardware and that particular rendering mode is not accurately represented (even if it works on real hardware, obviously). I'm not an expert on Saturn rendering modes by any stretch of the imagination, but I have been around the Saturn for a long time and I didn't know there was any way to mix modes like FFM apparently does, until you pointed it out. There are forks of Yabause that are actively developed and looking for feedback - maybe try contacting the devs of Kronos? Maybe they can look into and provide a means of capturing an accurate screenshot of a game running in this unique display mode, or maybe it already does - I have never tried FMM in an emulator since I still have the original game I bought back in the day (thankfully!).

		sibor		Jul 8, 2023
			nando said: yeah the lighting effects are very good in Fighters Megamix (better than those of VF2 Model 2 version), I think VF2 could have been closer to the Model 2 version if they hadn't gone for such a high resolution (which is even higher than the Model 2 version), moreover in prototype/unreleased games we recently had Starfox 2 on SNES, Dinosaur Planet on N64 etc so it would be so good if it continued with games like Eternal Darkness N64 and RE0 N64 and especially Virtua Fighter 3 Saturn (which was apparently finished and used Fighters Megamix engine)... for emulators it's a good idea to contact the developers (even if Yabasanshiro or Kronos are not as accurate as SSF and Beetle/Mednafen it can help to find ways for that if there are any), meanwhile if there are other ways (emulators or gui that saves interlaced and lossless videos or something else) let me know