sony trinitron + color emphasis bits = scrambled image?

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GradualGames
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sony trinitron + color emphasis bits = scrambled image?

Post by GradualGames » Thu Feb 16, 2012 10:25 am

Recently I decided to dim the screen when you hit "pause," in Nomolos. I used all three color emphasis bits. Works great in emulators, looks fine on a little 13 inch TV I have, but on my Sony Trinitron, it causes an extremely ugly bunch of scanline artifacts. I tried mucking with the settings on the TV, to no avail. Has anyone else seen this sort of thing on a crt tv, in a game that uses color emphasis?

I decided to use the monochrome bit instead for the pause screen, but it would have been slick to dim the screen with color emphasis.

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Post by tepples » Thu Feb 16, 2012 11:52 am

Then perhaps the warning in some older documents against using more than one emphasis bit wasn't full of crap. RGB units (Famicom Titler, PlayChoice, some TVs with a built-in Famicom) don't take very well to multiple emphasis bits turned on either.

What you can do to simulate the old effect is dim all elements of the palette by subtracting $10.

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Dwedit
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Post by Dwedit » Thu Feb 16, 2012 12:14 pm

I have an ancient Trinitron that's older than I am, and Battle Kid's pause effect works fine.
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MottZilla
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Post by MottZilla » Thu Feb 16, 2012 12:16 pm

Don't some other games do this? I have a Sony Trinitron too and never saw anything like this.

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Post by lidnariq » Thu Feb 16, 2012 12:24 pm

If all preemphasis bits are set, then color 1D ("black") becomes blacker-than-black and 01-0C no longer decode to a valid RGB color from the received YIQ values (Their brightness is approximately equal to unattenuated color 1D). So if it looks like scanlines restarting all over the place, maybe that's why?

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Post by Bregalad » Thu Feb 16, 2012 1:18 pm

The game Just Breed have all the emphasis bits set (most of the time, I think sometimes during lightning effects the game might briefly clear them).
Noah's Ark it like that too if I remember.
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Post by bunnyboy » Thu Feb 16, 2012 3:37 pm

Many clones also do not support the emphasis bits, if that is something you care about.

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Post by 3gengames » Thu Feb 16, 2012 3:44 pm

Using the emphasis bits is the lazy mans way of dimming the screen IMO. Plus, good luck porting your game to any RGB NES arcade system. (Which I want to do one day, sue me.)

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Post by Memblers » Thu Feb 16, 2012 4:04 pm

If it's not much trouble, maybe you could post the palette values you're using when that happens. But I guess it's specific to your TV, or some certain TV types.

I believe Super Spy Hunter sets all emphasis bits when you pause it. Munchie Attack does it when you lose all your lives (and yeah it didn't look too hot on the Playchoice, everything goes grey).

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Post by tokumaru » Thu Feb 16, 2012 5:57 pm

bunnyboy wrote:Many clones also do not support the emphasis bits, if that is something you care about.
Really? I didn't know about that. I guess I'll have to test my clones!

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Post by sdwave » Thu Feb 16, 2012 7:52 pm

Yep, I see some bending myself in one of the palette demos (pal test) on my Trinitron.

Try using $3f for black instead of $0d if possible and see if it helps any.

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Post by bunnyboy » Thu Feb 16, 2012 9:08 pm

tokumaru wrote:
bunnyboy wrote:Many clones also do not support the emphasis bits, if that is something you care about.
Really? I didn't know about that. I guess I'll have to test my clones!
I noticed it in one of Sivaks early games, so it was probably one of Yobo/NEX/RetroDuo. The 3 system clones weren't out yet.

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Post by Jeroen » Thu Feb 16, 2012 11:58 pm

They don't support it in what way? Simply not working or don't give expected behavior?

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Re: sony trinitron + color emphasis bits = scrambled image?

Post by thefox » Fri Feb 17, 2012 6:49 am

Gradualore wrote:I decided to use the monochrome bit instead for the pause screen, but it would have been slick to dim the screen with color emphasis.
Why not dim it by rewriting the palette instead?
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Post by thefox » Fri Feb 17, 2012 6:51 am

3gengames wrote:Plus, good luck porting your game to any RGB NES arcade system. (Which I want to do one day, sue me.)
Screen turning white when pausing the game hardly is game breaking behavior. Of course if the emphasis bits are used for other purposes (like keeping the palette dimmed all the time, like in Jungle Book, James Bond Jr and Felix the Cat), it's an entirely different deal.
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