MiSTer FPGA Forum

Hey all,

With the official release of the PSX core, I was wondering if we could get some more documentation on what some of those options do and who should be using them and in which cases? What are the recommended "default" settings for someone using HDMI, or someone using Analog?

For example:

Fixed HBlank
Fixed VBlank
Vertical Crop
Sync 480i for HDMI

I figure a lot of people will be wondering too.

Thanks!

Fixed HBlank gives me a 1 inch black bar on the left and right of my CRT. I'm sure there's more to it than that however.

RascalUK wrote: ↑Wed May 11, 2022 5:46 pm Fixed HBlank gives me a 1 inch black bar on the left and right of my CRT. I'm sure there's more to it than that however.

On a flat panel, Fixed HBlank looks "correct" in terms of pixel sizes being uniform. So a the most basic level (I'm not an expert), it seems like you'd want it off for CRT and on for LCD. Unless you want more of a CRT-like appearance on your LCD, which is totally valid too.

Turning on Fixed VBlank helped me fill out my screen a bit more by playing with the resolution settings, though with the loss of a bit of the image on the top and bottom. Not unlike the 5x scaling in cores that offer it.

I don't know what Sync 480i for HDMI does. I've toggled it a few times and can never tell a difference. Thinking about it now, maybe it's something to do with how the image looks in motion (which I haven't really tested).

More than any other core, games on PSX look wildly different from each other in terms of image quality and what settings look good. I think it's just the nature of the beast. I end up changing settings game to game, especially comparing 3D and 2D stuff. And MiSTer makes it clear just how often these games change resolution. Some 3D games look totally clean and pristine, some have tons of artifacts and blur no matter what I do.

From the name '480i', I expect that option to be for interlaced modes, like Tekken 3 has.

"Sync480i for HDMI" fixes the sync for some videos/fmv intros when using DirectVideo.

I noticed it in Gran Turismo 1&2. Menus and game are perfect, but intro scrolls out of sync.

(using an HDMI to VGA adapter for RGBs on a CRT TV)

Fixed HBlank/VBlank: Games can change the position/size of the image which will cause sync loss with the scaler & vsync_adjust=2. Enable these with HDMI to fix that. Positioning and shake effects will also work better.

Sync 480i for HDMI: This will keep the line count/refresh rate the same in 480i and 240p to prevent sync loss. If you enable this then interlace won't display correctly on a CRT TV.

paulbnl wrote: ↑Sat May 14, 2022 8:51 pm Fixed HBlank/VBlank: Games can change the position/size of the image which will cause sync loss with the scaler & vsync_adjust=2. Enable these with HDMI to fix that. Positioning and shake effects will also work better.

Sync 480i for HDMI: This will keep the line count/refresh rate the same in 480i and 240p to prevent sync loss. If you enable this then interlace won't display correctly on a CRT TV.

Thanks Paul. What about if using vsync_adjust=0? Are those hblank/vblank settings still necessary?

paulbnl wrote: ↑Sat May 14, 2022 8:51 pm Fixed HBlank/VBlank: Games can change the position/size of the image which will cause sync loss with the scaler & vsync_adjust=2. Enable these with HDMI to fix that. Positioning and shake effects will also work better.

Sync 480i for HDMI: This will keep the line count/refresh rate the same in 480i and 240p to prevent sync loss. If you enable this then interlace won't display correctly on a CRT TV.

Now I’m just even more confused. Should one use these options when using vsync_adjust=0? Is there any drawback at all to using them or is it just all positive?

It’d be nice to have a clear and concise guide of what these options should be set to for all main configurations.

mario64 wrote: ↑Sat May 14, 2022 9:31 pm
Thanks Paul. What about if using vsync_adjust=0? Are those hblank/vblank settings still necessary?

I know you asked Paul, but you still want to keep hblank turned on since it pretty much corrects aspect ratio for games. Vblank might still come in handy even when using vsync_adjust=0, especially if you want to fill the image better vertically for some games with the crop option.

Also, I'm curious, is your TV not capable of even handling vsync_adjust=1?

SegaSnatcher wrote: ↑Sun May 15, 2022 2:57 pmAlso, I'm curious, is your TV not capable of even handling vsync_adjust=1?

Can’t speak for him, but my TV (Samsung Q80R) doesn’t play nice with any signal that is not exactly 60.0hz. Manifests as excessive frame skip or distracting screen tearing near the bottom of the screen.

AtomicShroom wrote: ↑Sun May 15, 2022 3:46 pm

SegaSnatcher wrote: ↑Sun May 15, 2022 2:57 pmAlso, I'm curious, is your TV not capable of even handling vsync_adjust=1?

Can’t speak for him, but my TV (Samsung Q80R) doesn’t play nice with any signal that is not exactly 60.0hz. Manifests as excessive frame skip or distracting screen tearing near the bottom of the screen.

Same here. Mine is a Samsung Q60R

Samsungs in general have issues with some deviations from 60hz. For me the Genesis core would get really weird frame ghosting issues on vsync_adjust=2. But 1 usually worked.

hblank and vblank should be on all of the time in my opinion with a rare exception for some games that may use that border area. A good example of when to use hblank and vblank together is final fantasy 7. Go out to the world map and enter a battle, with only hblank on there's this weird resizing and vertical position change of the screen, because it's changing back and forth from 256 to 240 (or was it 240 to 224, can't remember). With vblank on it looks "correct" without the overly wide inaccurate look of having hblanks off.

hblank was originally added because games that have excessive screenshake effects would cause screens to lose sync. vblank was added to counteract some of the weird behavior of the hblank setting being turned on as well.

Playstation games can vary in terms of how many horizontal lines they draw, and worse it can vary within game. Like FF8 seems to be 224p on the field, but 216p in menus. If you were using integer scaling at 1080p, you'd see a bounded 4x on the field but in the menu 5x nearly filling the screen, and my flat panel loses sync when it has to make that transition.

Fixed vblank seems to force everything to 240p and draws black bars above/below if needed. That solves the resync problem but introduces larger black bars, especially if you like to fill the screen with integer scaling off. With vblank on you can also select a vertical crop, so you could pick 216 @1080p for a 5x scale, now your FF menu looks beautiful but you will be losing a bit of information on the field, so it's a trade-off.

So in short, pick fixed vblank for the sake of scaler stability in multi-res games, but then you have to choose between black bars or a crop.

I've got a CRT monitor here side-by-side with a flat panel, but I'm having trouble drawing conclusions as to whether a fixed hblank is or isn't more accurate. If someone knows the details here I'd love to here, otherwise I'll try to investigate more later.

While we're on the subject, what does the Stereo Mix 25%/50%/75%/100% setting do?

What it sounds like - controls the degree of mixing independent left and right sound channels into center. It's most useful when using headphones, as full separation is very disorienting.

Thanks for the explanation, guys !