When the Genesis was released in 1988, very few arcade boards at the time was able to produce the same video resolution (320x224). There are a lot of systems with a much better hardware but using a lower resolution, like Namco System 2 (288x224), Konami TMNT2 Based hardware (288x244) or Neogeo (304x224). The same could be said about the home consoles (SNES = 256x224).
Is there any technical reason for that?
TV overscan. 320 pixels is NOT what you could see - overscan meant that of the 320 pixels, you might see 304 down to as little as 288 pixels, but it varied from TV to TV, so they allowed more with guidelines on where to keep the action and stats so that nearly all TVs showed all the "important" pixels. That same TV frame on 256 wide modes means you might see as little as 228 pixels - the same rules about overscan apply to all consoles. It's only with the advent of digital TV circuits and especially digital displays that overscan has dropped to almost nothing. You STILL lose several pixels on either side of the display on most TVs, even modern LCDs. If you know how to get into the service mode of the TV, you can adjust the overscan to a certain amount - perhaps even eliminate it altogether depending on the TV.Quote:
Originally Posted by tisurame
Hum. I don't think the overscan area eat that many pixels, and the overscan is much less prominent on the horizontal resolution. On the vertical resolution there are a lot of pixels hidden by the overscan area, but since Genesis games use x224 (and not x240), it's also a negligible problem.
For example, most PSOne games use 320x240. Then, a SDTV will only display 224 (vertical) pixels.
Overscan doesn't seem to be a valid reason. The SEGA arcade boards since the mid 80's started to use 320 pixels - so, I'm not sure why others companies did not do the same.
No doubt, with the resolution increase there is a huge impact in the viewable area of the game, and since most games are horizontal oriented, it makes much more sense to increase the horizontal resolution to 320 pixels and with that achieve a near perfect 4:3 aspect ratio. You can see a lot of arcade boards with multiple CPUs, sound chips and other crazy stuff - but using a resolution less than 320. So, I was wondering why.
Overscan wasn't the reason. There was a giant border around all games (without exception) to account for that. But it would eat up a few pixels. I know that if you draw a perfect circle in a game that runs at 256x224 it will be horizontally stretched when viewed on a TV screen. This is why many SNES games look "fat". Compare Earthworm Jim, for example. Many, many SNES games are guilty of this. However if you draw a perfect circle in a game that has a 320x224 resolution, then you will get a very nearly perfect circle on the TV screen. 320x224 is closer to a square pixel version of a TV's aspect ratio. 256x224 does not use square pixels and that is taken into account during design as often as it should have been. Also, many games that were designed for 256-wide screens on other systems were squished inside a 320-wide screen ont he Genesis and given a status bar to make up for the extra screen real-estate it afforded like Devil's Crush/Dragon's Fury and Zombies ate my Neighbors. Also Blackthorne.
Uh - no. 320x224 is NOT square, it's almost perfectly NTSC PAR (10:11). It's CLOSER to square than 256x224, but not so much that you can ignore the aspect ratio. It was as I said - overscan reduced the usable space on the screen, meaning you needed a slighter higher horizontal resolution to do more detailed images.Quote:
Originally Posted by Joe Redifer
Yeah, that's pretty much exactly what I said:Quote:
Originally Posted by Chilly Willy
320 x 240 would be square, but the 320x224 area is not being stretched to the edges of the screen, so in development it can basically be treated as square pixels without much worry of distortion when the image is displayed on a TV screen. But your overscan explanation is common sense. The higher resolution, the more detailed the images. But it doesn't answer tisurame's original question. Lots of other game systems of the time which also worked inside the same overscan area predominantly used a lower resolution. Even the Neo Geo you can see a bit of black pillarboxing on many NTSC sets (though very, very slight). Overscan was not the reason for the 320 mode otherwise all systems would have 320. Genesis had a 256 mode as well.Quote:
Originally Posted by Joe Redifer
I will accept that overscan IS the reason for the 224 instead of 240.
The Genesis' 40 cell wide mode just adds another column of 8x8 cells. I assumed this didn't affect the sprite pixel aspect ratios at all unless the developer wanted it to.
Lots of old computers had a predominant resolution of 320 x 200, including the C128, Amiga, Atari ST, Apple IIgs, Tandy CoCo 3, and PC VGA in 256-color mode. I guess that was probably different in Europe.
Basically, running a game in 320 mode does not mean you take a hit in the sprites nor do you gain anything from the sprites by running in 256 mode. The Genesis accommodates for the increase in resolution in 320 mode. As for their aspect ratios of course it changed. One is 256 pixels across and the other 320 pixels across all displayed in the same TV space.Quote:
Originally Posted by sheath
Um, actually yes... though the other way. The sprite limits are increased in H40 (320) mode. On the other hand, H32 (256) mode lets you get away with less pixels, which can be useful when you're really tight on memory usage.Quote:
Originally Posted by Joe Redifer
What I was asking without asking is if the sprites' aspect ratio changes between 32 Columns and 40 Columns. I think I know the answer to that question though because I've seen people talking about sprites getting stretched and needing to be redrawn for 320 wide mode.
ALL pixels get stretched. The screen size remains the same, the pixel size change. Pretty much the same way as for different resolutions in computers.
Is the background color that goes outside of the normal game screen considered part of the horizontal resolution?
256 wide mode and 320 wide mode occupy the same space on the screen. All that changes is the width of the individual pixel. That means the in 320 wide mode, more pixels are visible and they are closer to square in aspect ratio. The "closer to square AR" is helpful with art, but not crucial as you can see from all the consoles that have 256 wide displays. The "more pixels are visible" is the REAL improvement since that means you can show more detail.
No, but it technically should. Anything that is not part of the horizontal blank range should be considered the active line and therefore contribute to the horizontal resolution. TECHNICALLY, most "320" wide display modes are closer to 340 to 360 wide with the extra pixels not addressable and automatically filled with the background color. Now you're getting into the nuts and bolts of the VDP, so it will vary on the exact console, and sometimes revisions of the console.Quote:
Originally Posted by sheath
At this point you should probably just ditch the concept of resolution and use frequencies, considering how TVs have absolutely no concept of pixels at all. The idea of pixels is imposed by whatever generates the signal, not the display.Quote:
Originally Posted by Chilly Willy
Or in this case, even the pixel width can change within a given scanline... (and technically those shouldn't be even considered pixels, but rather VDP clock cycles)Quote:
Originally Posted by Chilly Willy
The genesis uses 320px because it's awesome.
(Honestly I have no idea, it's great that it does though).
Okay, so the fact that I typically don't see the boarder color on my TVs and properly cut that section out when I make videos isn't lowering the resolution? That jives with the fact that when I record a 320 wide game and crop out the border the videos and pics are all 640x448.Quote:
Originally Posted by Chilly Willy
D1 NTSC is 704x480 and goes from the end of the hblank for one line to the start of the hblank of the next line as well as from the end of the vblank to the start of the next vblank, summed over two fields. Consoles tend to output what is referred to as D1/2, which is 352x240. That has the exact same characteristics, going from blank end to blank start, but is 240p instead of 480i. 352x240 is exactly 4:3 for the display aspect ratio, taking into account that D1/2 pixels have a PAR of 10:11. If you calculate those values back, 320 wide with 4:3 DAR and NTSC PAR SHOULD give ~219 lines high, so the Genesis 320 has pixels just slightly wider or they merely accept that 224 will be a little taller than 4:3 just to keep the display height an even number of cells in height.Quote:
Originally Posted by sheath
Sega was an arcade game developer with current arcade hardware that ran at a resolution of 320 x 224 and previous arcade hardware that ran at 256 x 2224. Supporting those resolutions with their new console just made sense for porting their exclusive hit arcade games.
The Mega Drive was also brought in as competition for the PC Engine, which had games using a resolution of 336 x 240/224.
If anything, not supporting the 320 x 224 resolution would have been questionable. I'm guessing that all of the nice looking PCE games which only used the 256 x 224 resolution factored into Nintendo not bothering to go beyond that (for practical use) with the Super Famicom.
If that's the cause of blurriness than it's not awesome.Quote:
Originally Posted by Kamahl
This is almost certainly the real reason. :)Quote:
Originally Posted by Black_Tiger
Well... But what are the disadvantages of using a higher resolution? I suppose it's just not a matter of choice, otherwise Nintendo would choose to also use 320x224 with the SNES.
If I recall it depends a lot on the system bus speed, which is also usually dependent on the main CPU speed in some way. The SNES' DMA to its PPUs is also significantly slower than the Genesis' DMA to its VDP.
That is all in the nitty gritty engineering of the systems though. Nintendo obviously thought that more colors, the completely sample based sound chip, and Mode 7 more than made up for anything their competition could show. That is in fact how they marketed the SNES.
Um, takes up more memory? =PQuote:
Originally Posted by tisurame
And I guess Nintendo stuck to 256×224 because that's what the NES used (even if they never implemented NES compatibility in the end). Note the SNES does have a 512-pixels wide resolution (though if I recall correctly it's faked by using blending, which is why the blending hardware isn't available in that mode).
Well, there are related pros and cons with various consoles, but they are simply related to resolutions, not a result of it. The Genesis can't shade as well or pack as much detail with the same variety of color as the other consoles, so the higher resolution helps with dithering and defining detail using fewer colors. The PC Engine can only line up 256 pixels wide worth of sprites per screen, so using its higher resolutions means less sprites on-screen than the Genesis. The SNES technically has higher vertical and horizontal resolutions, but I assume that they are also tied to various limitations (like interlacing) since they aren't commonly used.Quote:
Originally Posted by tisurame
If the SNES retained all of it's color abilities, but used a 320 pixel-wide resolution, it would take more memory to display the same proportionate amount of artwork per screen, so the lower resolution used in almost every SNES game keeps cart sizes smaller than if they ran in a higher resolution.
It has nothing to do with the blurriness.Quote:
Originally Posted by Curryman123
OK. My main question is if the lack of colors from the Genesis hardware is somehow related with the higher resolution.Quote:
Originally Posted by Black_Tiger
Cons = fewer colors
Pros = higher resolution
Is it safe to assume that?
Nope, no relation in this case.Quote:
Originally Posted by tisurame
Now we could debate for ages about cutting corners in some places to add in others, but that wouldn't be directly related to the resolution.
The lower amount of colors is directly tied to the low amount of memory, period. I guess this is because they tried to put CRAM on-die instead of having it separate (though having separate CRAM and color DAC could have potentially bumped up the price of the console quite a bit).
Did making CRAM a part of the VDP also make it impossible to put traces on the expansion port and cartridge port allowing for CRAM expansion? If it didn't I wonder how much more that would have cost to do.Quote:
Originally Posted by Sik
No, given that all lines are available in the VDP (and some more... e.g. you can genlock two VDPs together). In fact, arcades based off the VDP use external CRAM and color DAC. They were probably just being cheap in this case =PQuote:
Originally Posted by TrekkiesUnite118
yeah....I figured later that I spat out some nonsense.Quote:
Originally Posted by Kamahl
Nonsence. Overscan has nothing to do with horizontal resolution, like 320 pixels on Genesis. Overscan is related to scanlines, so in case of Genesis, to 224 pixels in vertical resolution. If Genesis used 320x240 there would be a lot of TVs that wouldn't display the whole picture because 240 scanlines at 60 Hz is simply too much for normal 15 kHz TV set.Quote:
Originally Posted by Chilly Willy
And why 320 pixels On Genesis and only 256 on SNES? Because Genesis :rock: does...
Technically Sega reported that there was one row of tiles at the top and the bottom that weren't guaranteed to be visible on TVs... and that's for 224 lines, so basically 240 lines would have been a waste (the SNES doesn't have a 224 lines mode, so either you're stuck with reduced vblank time or you're forced to use raster effects to get that extra blanking time).
What are you, an idiot? Of COURSE there's such a thing as horizontal overscan!! Don't open your mouth if you haven't the vaguest idea what you're talking about. :hand: :shame:Quote:
Originally Posted by Tom M.
In the end both of you are wrong though because I really doubt Sega went with 320×224 because of any overscan issues =P (in fact I think the only thing that may be even remotely related to that is the V28/V30 switch, given how it only works properly in PAL, which shows more lines)
If you believe the V28/30 switch is remotely related, then you MUST also believe the H32/40 switch is related, even if remotely, for the same reasons. :)Quote:
Originally Posted by Sik
In any case, the SEGA Software Guidelines clearly state that games may not put important info into either the first or last columns of the display due to horizontal overscan. If you NEED 256 pixels for your display and they MUST be visible pixels, you have no choice but to run in H40 mode.
it's because it has MEGA power
Not really. The V28/V30 switch affects the amount of space the rendering area takes up on screen (vertical size changes, pixel size remains the same), while the H32/H40 switch doesn't (horizontal size remains the same since the size of pixels change). In fact, you get overscan in both H32 and H40 modes.Quote:
Originally Posted by Chilly Willy
Yes, but H40 gives you more VISIBLE pixels to mess with. That's the point. How they do it is immaterial.Quote:
Originally Posted by Sik