Carving the Super Nintendo Video System

> They probably did not pick that number at random. 224 is a number evenly divisible by 16 (224/16 = 14) which means it plays nicely with the graphic rendering pipeline tilemaps.

This was something that took a bit to figure out, but made so much sense to me after I had been playing around with trying to learn game programming when I was a kid.

CGA/EGA/VGA all had popular 320x200 modes.

The NES was 256x224, as was the SNES (although it did have higher resolution modes), and that was really a TV limitation.

Meanwhile, Pac-man was 288x224 in the arcade.

So none of the Pacman clones on the PC would ever look 'right', and even the Pacman games on the NES that were made by Namco didn't look right either. There were always hacks like giant characters because the tiles for the map were smaller, or you'd get a scrolling world (Gameboy, Tengen versions), other kinds of distortion, non-original maps...it was all just weird and frustrating when you're trying to play the 'arcade' game at home.

But after learning the details of the machines, how sprites worked (and then coming to the conclusion that they just didn't have any other choice), was such a huge 'a-ha!' moment for me. Let's not even get into the fact that pixels aren't square on those resolutions on the PC.

And then it became almost an instant reaction when I'd see a Pacman port or clone, and try to figure out what size the world was, what size the tiles were, what size the sprites were....

Also check out Rodrigo Copetti's article about SNES architecture. https://www.copetti.org/writings/consoles/super-nintendo/

> 59.94Hz is such a weird number. Isn't the power grid running at 30Hz and TVs used to double it?

No power grid I know of runs at 30Hz. North America (where NTSC was designed) and a few other places[0] run at 60Hz.

[0] https://en.wikipedia.org/wiki/Mains_electricity_by_country

> Trivia: Besides the annoying black band, the game code was also rarely revised to account for the VSYNC which occurred at 50.00697891Hz instead of 60.098Hz. This resulted in game running 17% slower than intended. European gaming was a real dumpster fire. But luckily without the internet we did not know about it.

This one hits home. Although my examples are not specific to the Super Nintendo, it reminded me of the first time I played/watch Sonic the Hedgehog on the Mega Drive (Genesis)

I wasnt impressed with the game. It looked clunky and just felt slower compared to the Master System version. It wasn't until the rise of youtube I realised the difference in speed between the NTSC and PAL is huge. Its not just the speed of the game, but the Music. It sounds horrible on PAL!

Don't get me wrong - I knew about the PAL during the 16-bit, and the need for the "black box" but I didn't realise how much of a difference it was. I am sure the console magazines at the time would say the difference is minor in most games. One of the exception (honesty) was DooM on the SNES. The NTSC version had a bigger screen.

I remember being good at Punch-Out when I was a kid on the NES. I could beat Mr. Dream (or Mike Tyson) in the first round. Of course, I was playing the PAL version. If there was some kind of competition in the USA, I would have been destroyed in the first round! I would have been convinced I was framed!

Past times, right?

I think TFA has a typo; it suggests the aspect ratio is 8:6 which would be the same as 4:3, my math says 8:7

Doesn't this miss the part where the 256x224 (8:7) output resolution gets stretched into a ~4:3 (actually 64:49) image?

The SNES has a dot rate of ~5.37 MHz which is slower than the square pixel rate defined by the ATSC standards of ~6.13 MHz. It's exactly 8/7 slower, so pixels are stretched horizontally by 8/7, causing the 8:7 resolution to be stretched to (8/7)*(8/7)=64/49, which is close to 64:48 = 4:3.

> Result in an aspect ratio close to 4:3. This would mean 224*(4/3) = 298 visible dots.

If you consider what I mentioned, the factor would be (4/3)/(8/7) = 7/6, so they would have to choose something closer to 224*(7/6) = 261.33... visible dots. Which is much closer to what they chose with 256.

Meanwhile I was using the RF output and a switch box to pick between SNES and TV antenna.

The 8:7 artwork aspect ratio is visible in a few SFC/SNES ports to other platforms, like ROCKMANX3 / Mega Man X3. The PSX/Saturn/PC versions of that game retain the original art unstretched and instead add stage-appropriate pillarbars to pad the 8:7 out to 4:3. Very distracting to play since I'm used to the original ver. Check out some screenshots of the Saturn ver here and you can see it — everything is slightly too skinny: https://segaretro.org/Mega_Man_X3

I wonder how long it takes Fabien to write these up. So many details, so clean.

How much of the SNES resolution is hard-coded in the console hardware, versus being something the cartridge could drive? Could a cartridge that didn't need to load sprites (e.g. because it had its own coprocessor), and had its own onboard clock, theoretically drive more than 256 horizontal pixels per line?

Are there any emulators that accurately simulate the CRT appearance instead of just drawing the pixels straight to the window? This could be done performantly with a GPU shader. (I recall some emulators having an aesthetic scanline effect you can enable, but that's not the same thing.)

Wow. I had no clue that an input device actually had any sort of control over the drawing of a CRT. I thought you just throw out signal at a certain timing and that’s it.

Also this article was wonderful in the way that it didn’t waste a word. Very concise.

The power grid in Japan runs at 50hz in half the country and 60hz in the other half.

I was hoping there'd be some insight on how this led to the design of such amazingly iconic games :)

I LOVED SNES and was unfortunately never able to convince my immigrant parents to buy me one

Thank you for the writeup. Super interesting

"Don't sit too close, move back a bit". Any truth whether sitting too close makes for bad eye sight? Wondering of any effects (e.g. leakage) that goes past the target screen area.

Hires mode games list is incomplete. I wonder, if it would be possible to quickly detect if game has a CPU instruction to toggle hires mode on?

Why does the SCART connection use capacitors in the RGB lines? (last picture)

Doesn't that block low frequency signals (e.g. an all-blue screen)?

>game running slower

Eh, jus try Super Mario World with an emulator on PAL settings with an NTSC ROM.

The counter and music will go much faster.

> European TVs, especially those in France, came with SCART connectors

This is, as far as I can tell, an understatement - almost all TVs in europe offered SCART ports, the standard just originated from france.

I haven’t seen carving used like this before. Is it a common usage?