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  • Joined: 05 Sep 2013
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Image "out of screen borders"
Post Posted: Sun Jun 15, 2014 1:34 pm
My Master EverDrive finally arrived so I started testing my WIP homebrew on my own (PAL) Master System. Colors are bleeding a lot, and there are many 'ghost' images around my characters, I guess it's because of the RF modulation... but I can live with that. What's really really disturbing is that it looks like the image isn't horizontally 'centered' on the screen, thus the first column of tiles on the left is almost completely hidden and to the right of the image there's a lot more of backdrop color than what I was expecting. :|
Any suggestions on how to fix that?
I also noticed there's a 'screw' that sticks out from the RF modulator box that sits on the PCB... what's for?
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Post Posted: Sun Jun 15, 2014 3:37 pm
Don't use the leftmost column (if you have horizontal scrolling then it's hidden anyway), treat the remaining 248px as centred and potentially cut off a bit at the edges. Overscan is weird that way.
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Post Posted: Sun Jun 15, 2014 8:08 pm
You mean it's absolutely 'normal' that the first -say about 6- pixels to the left do not appear on screen? Wow, I didn't expect that for sure (and I didn't read any suggestion about not using the leftmost column of tiles anywhere in any document... or have I overlooked that?)
OK, it's time I seriously re-think about some decisions I took when I started this... :|
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Post Posted: Sun Jun 15, 2014 8:34 pm
Yes, especially on older TVs. I think the Sega docs say something about it, and it's come up a few times for me personally. See also this: http://en.wikipedia.org/wiki/Safe_area_(television) - I'd say the rightmost 248 pixels is in the "action safe" area, but you should allow margins for text.
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Post Posted: Mon Jun 16, 2014 12:26 am
I believe the 'screw' is for tuning. It sets the frequency, so if you change it you'll need to re-tune your TV to pick up the signal again.
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Post Posted: Mon Jun 16, 2014 8:09 pm
Left and right 16 pixels are always considered not text safe. Vertically there's no issues.
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Post Posted: Tue Jun 17, 2014 12:16 pm
TmEE wrote
Left and right 16 pixels are always considered not text safe.


So much? But if I don't set any text there, can I assume for everything else that 8 pixels both sides are enough?
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Post Posted: Thu Jun 19, 2014 12:40 am
The left and right 16 pixels are considered not text safe, and left/right 8 pixels not action safe. All really important stuff should be off the edges.
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Post Posted: Thu Jun 19, 2014 1:57 pm
I see. Thanks! :)
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Post Posted: Thu Dec 31, 2020 2:25 pm
I'm coming back to this as I am working on maximising the text area for the Phantasy Star retranslation. As I understand it, the SMS screen has the rightmost 248px centred relative to the screen; the leftmost column is often completely invisible. The rightmost 8px and the next 8px on the left are likely to be partially obscured by the screen edges. So here's a mockup:



And a simulated view of it:



With a real game screenshot inside:



We see that some important UI is starting to be cut off. Is this accurate?

My memory is that my TVs used to partially cut off the red part and not the rest, as described in the first post above. Later on I used service menus to reduce overscan anyway. But I guess as developers we should avoid putting anything important in the red and yellow areas - but that can mean an asymmetric look elsewhere (unless you hide the left column).
areas.png (388 B)
areas.png
psj.jpg (34.26 KB)
psj.jpg

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Post Posted: Thu Dec 31, 2020 3:01 pm
Is the cutoff different on PAL TVs?

Trying to think hard if I heard discussion on that, and no the only thing that comes back is NES color issues (which was a console issue and not the TV format itself, so irrelevant).

My guess is that the higher vertical resolution of PAL would've cut off less on the corner of the screens (due to black bars). That is, more concerned about cutoff in the row direction. That was the worst I've seen of cutoff on NTSC TVs and hardware. I've heard the official Genesis docs recommended not putting important info in the top or bottom two tile rows.

But to speak of columns, losing about a column and half of "visible" area sounds about the worst I can remember seeing.
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Post Posted: Thu Dec 31, 2020 3:49 pm
I think the horizontal timing is the same for PAL. The bigger borders mean the display is closer to the middle of the screen where the horizontal cutoff is smallest...

I suspect the amount of overscan is greater on older TVs with more curved tubes. I guess the best thing would be some photos to demonstrate it, but most people nowadays won't have a 1980 TV to test on.
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Post Posted: Thu Dec 31, 2020 6:26 pm
Maxim wrote





The red vertical line is like the tile row the SMS "sacrifices" to offer horizontal scrolling in the games.

The most notorious example I can see is in the first stage of Alex Kidd in Miracle World: While you are just falling down the Mount Eternal, the SMS screen is 256x192, but when you hit the botton of the stage, the stage orientation changes from vertical to horizontal and, when this change occours, you can note the left part of the game's screen turns black, meaning the resolution lost a row of the screen, making it goes to 256x192 (or 32x24 tiles) to 256x184 (or 32x23 tiles).

In the case of Maxim's TV, you can't see the lost tile row, once these tiles are off screen...
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Post Posted: Thu Dec 31, 2020 7:49 pm
rouken wrote
the left part of the game's screen turns black, meaning the resolution lost a row of the screen, making it goes to 256x192 (or 32x24 tiles) to 256x184 (or 32x23 tiles)
248 × 192, actually. You lose a column, not a row.
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Post Posted: Thu Dec 31, 2020 8:06 pm
I guess I should make a test ROM and ask people to photograph it on their TV...
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Post Posted: Thu Dec 31, 2020 8:37 pm
Tom wrote
rouken wrote
the left part of the game's screen turns black, meaning the resolution lost a row of the screen, making it goes to 256x192 (or 32x24 tiles) to 256x184 (or 32x23 tiles)
248 × 192, actually. You lose a column, not a row.

My fault, but you got the idea... ^_^



Maxim wrote
I guess I should make a test ROM and ask people to photograph it on their TV...

Or even better: A SMS version of the 240p Test Suite!! Just kidding... XD

EDIT: Wait!! There's a SMS version of this Test Suite? I'm really living under a rock, and my joke was lost... -_-
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Post Posted: Fri Jan 01, 2021 4:50 pm
yes you can check 'Grid' with SMS Test Suite, the outer 'ring' of tiles is red, the second outer 'ring' is yellow to help identify how much gets cut out
grid.png (601 B)
grid image in SMS Test Suite
grid.png

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Post Posted: Fri Jan 01, 2021 8:45 pm
Are there any existing photos of this stored somewhere?
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Post Posted: Mon Jan 04, 2021 12:41 pm
not that I know
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