SNES correct aspect ratio in Generic 4:3 mode Line4x

[Daneeall]

Basicly I’m trying to calculate an H. Sample rate Generic 4:3 Line4x for  SNES.

The formula I know: [pixel clock\(vertical refresh * scanlines)=h. sample rate*4] dosen’t go very well here.

I got 5369318,18\(60.09*262)*4=1364,19 But this value is even lower than the generic defaults, so the image is squashed vertically even more.
I don’t like “optimised” mode for SNES cuz some games looks messy in some circumstances due to internal resolution switching, so the Generic 4:3 Linex4 is the best way to play SNES to me. The only thing is the aspect ratio i’d like to correct.
I beleive that there is something to do with 8/7 par value but I’m not sure.

• This topic was modified 3 months, 1 week ago by Daneeall.
• This topic was modified 3 months, 1 week ago by Daneeall.

[marqs]

What do you mean by ‘correct’ aspect ratio? Equivalent on how it’d look on a CRT or something closer to 8:7?

If you want to fit SNES image horizontally, then your sampling rate needs to be h.active/0.75. To fit vertically, v.active needs to be 224 (a few games would need 240, though). Then your display would need to be able to scale resulting 1280×896 resolution into whichever aspect you consider correct (4:3 or 8:7). For compatibility reasons default parameters have been selected so that resulting resolution is 1280×960 with small borders on each side but with aspect that should be close to CRT when PAR is preserved by the display.

[Daneeall]

I appreciate your attention, thanks. I’d like to see circles as circles rather than ovals, I think it’s 4:3 aspect.
So for the SNES h.sample rate will be 1280\0.75=1706.66 (Generic 4:3 Line4x) am I right?

May I ask you what the 0.75 value is?
And if the formula [pixel clock\(vertical refresh * scanlines)=h. sample rate*4] is the right way to calculate h.sample rate for the other consoles in Generic mode Line4x? And if it is, then why it doesn’t work in SNES case?
I made the same calculations with that formula for N64 and Genesis and it’s apparently looks OK

[marqs]

Circles across games may not look the same, but 0.75 (more accurately 256/341) is just the portion of a scanline SNES produces active picture data. With h.active=1280 and h.samplerate ~= 1707, the active width is sampled to the 1280 pixels sent to output without any over/underscan. However, as mentioned above, it does not guarantee correct aspect ratio but just ensures optimal fitting in X-axis. You can adjust samplerate to tweak aspect to your preferences if needed, but most likely that results to some under/overscan unless your display provides some aspect ratio controls.

I’m not sure why you want to use above formula if you don’t like optimized modes. It just results to integer-number of oversampling which you don’t want with most sources if aspect ratio is the priority. The last number in the equation (4 above) also depends on LineX mode and source, see here.

[Daneeall]

Using the formula from above tends games to look clear enough, and sharp enough wich is acceptable to me, without necessity of switching “optimised” modes from game to game, or suffer from ingame resolution switching when the main gameplay is displayed in one resolution and internal menus in another.
I just love how the SNES looks with this samplerate, thanks.
Actually if to use the same calculations but corrected with data from the table you’ve provided, we’re getting pretty close results:
5369318,18/(60,09*262)*5=1705,24
So if I got this correctly, for the SNES Generic Line4x, the last multiplier of the formula determines the aspect ratio: *4 is for 8:7 and *5 is for 4:3 am I right?

• This reply was modified 2 months, 3 weeks ago by Daneeall.

[marqs]

If you want ~8:7 aspect in generic L4x mode, you need to indeed have samplerate of 1364 and h. active of 1024. Your monitor must also preserve 1:1 PAR of resulting 1024×960 resolution.

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