[Not64] Bug? — only renders at 480p internally even when using different video modes

[Nintendo Maniac 64]

While doing some tests using the Dolphin emulator with dumping screenshots at native 1x internal render resolution, I noticed that Not64 seems to always internally render the game at 480p and then will instead up/down-scale to the corresponding video output mode, whether 240p, 576p, etc. In other words, you only get a razer-sharp perfect pixels in their unaliased glory when Not64 is outputting a 480 pixel-high video signal even if you're playing PAL games or the like (though that shouldn't matter since even the NTSC version of games render at 480p rather than the 240p they're natively coded for).

The main issue is that, as I've mentioned elsewhere previously, only the European version of BattleTanx: Global Assault works in Not64 (and Wii64). Being a 25fps PAL game, I prefer using one of the 50Hz video output modes in order to retain proper frame-pacing with my display therefore running at 50Hz for an exact 2:1 frame-cadence but, of course, none of the the 50Hz video modes output at 480p and always result in that aforementioned up/down-scale blur.

I've attached a slew of screenshots in the attached ZIP depicting what I mean via Mario Kart 64, and I also took some screenshots of the first "Challenge" level of TimeSplitters 2 as a sanity check to make sure Dolphin itself wasn't just rendering everything at 480p (look at the stairs—it seems the US version is actually downsampled from the EU's 576p for some minor SSAA; also don't mind the difference in brightness—the PAL version is dimmer for some reason).

[Extrems]

For 576p, this is intentional as many games also stretched vertically from a 320x240 framebuffer on PAL.
For 240p, it's actually 640x240 with 3x MSAA.

[Nintendo Maniac 64]

For 576p, this is intentional as many games also stretched vertically from a 320x240 framebuffer on PAL

This confuses me though because NTSC games would use a 240px vertical framebuffer (actually, according to Cen64, it's a teeny bit less: 237px vertically if I recall correctly) and yet Not64 still natively renders them at 480px vertically, implying that Not64 is overriding the framebuffer. So why is it that Not64 isn't similarly overriding the framebuffer to natively render games at 576px vertically when using such output video modes?

[Extrems]

1) That's a bug with the video interface. The framebuffer is really 320x240.
2) UI textures with point sampling look nasty that way. We also can only do up to 640x528 in a single pass.

[Nintendo Maniac 64]

2) UI textures with point sampling look nasty that way. We also can only do up to 640x528 in a single pass.

Personally I think it'd be an interesting option for additional video output modes and then just padding the rest of the 528 with black bars under the assumption of overscan, but it's your emulator so I'm not exactly going to demand that you do this...

Of course, another option to mitigating the issue of either having the PAL framerate judder or having a blurred video output would be the ability to run PAL games at the slightly-slower 23.976fps which would pair great with Not64's existing built-in "Scale Pitch" audio setting. This combined with a 480p video render & output would allow for maximizing still-image clarity while also improving frame-pacing since 24fps at least fits into 60Hz with a 3:2 frame-cadence rather than the ugly 12:5 frame-cadence you get of trying to fit 25fps into 60Hz.

[Nintendo Maniac 64]

Apologies for the double-post, but I didn't want to edit this into my previous post since doing that may not activate forum post notifications (which I figure Extrems has enabled since they seem to reply quite promptly).

1) That's a bug with the video interface. The framebuffer is really 320x240.

Maybe I'm misunderstanding, but I definitely remember Cen64 used to be outputting a 320x240 video signal but three horizontal rows of pixels were simply doubled, meaning there were really only 237 unique rows of pixels. Just a couple months after I pointed this out and referenced how a real N64 outputs its video signal, Cen64's behavior was changed to instead output 320x237 without the doubled pixels (keeping in mind that Cen64 used 200% nearest neighbor by default, so it was 640x480 with three 2-pixel high rows that were doubled which was later changed to 640x474).

I went digging through archive.org's snapshots of the Cen64 forum and located the posts in question:

• https://web.archive.org/web/20210614064 ... 1f16#p1633
• https://web.archive.org/web/20180904041 ... t=50#p2372
• https://web.archive.org/web/20160818074 ... 263f#p2460

The only reason I bring this up is because I just noticed that the screenshots on The Cutting Room Floor are also 320x237 for Mario Kart 64, the first BattleTanx game, and BattleTanx: Global Assault, with there even being a note on some of the change history for the screenshots saying nothing more than "Native res" replacing the previous revision of the screenshots being 320x240.