Jump to content
IGNORED

NTSC core for VBXE?


Joey Z

Recommended Posts

Thank you very much mono for the detailed information. Unfortunately, without the base knowledge or experience to build on, it's still Greek to me, but hopefully someone with a broader knowledgebase and experience can take your information and make use of it to help us get closer to our dream of having flashable palette for the VBXE.

Link to comment
Share on other sites

Well, given that the GTIA only core has a single palette, and the regular core has 4, perhaps we can use that to help reverse engineer how the palettes are stored in the cores?  I do know that the other 3 palettes in the core default to all #000000 (RGB) on power-up.

Link to comment
Share on other sites

You modify palette entries by loading the RGB values into the MB1-MB3 registers, then store the palette index into MB0 and lastly store $C0+the palette # into MSEL.

So, it's an easy process to download from an .ACT file though that's not to say it's stored internally that way.

The GTIA only core - it would have lots of spare space but it's an unknown whether the palette is generated or stored differently.

Link to comment
Share on other sites

You guys are discussing different cores, I'm assuming they're from different versions, but I only see two versions on Lotharek's store; the VBXL and the VBXE. So where do you get a GTIA-only core, and what are the other versions for? What is the "regular" core? How do you get them? In the VBXE files zip I see something about a 5200 core, but I don't that version for sale. Do you just buy the VBXE from Lotharek and then flash it to whichever core you want?

Link to comment
Share on other sites

From memory there's 4 core types that have been developed, possibly more, that perform different functions.

 

1. The stock core which has had ongoing maintenence and improvement so generally you'll see versions around from 1.22 thru 1.26.

2. There was a VGA core which allowed using a 30 KHz instead of 15 KHz monitor but required a faster crystal (?) and was GTIA only (?)

3. The GTIA only core.

4. A sound processor core, unsure if it went further than proto stage or had any general release - reassigns output bits and turns VBXE into a digital sound processor.

Link to comment
Share on other sites

7 hours ago, Rybags said:

From memory there's 4 core types that have been developed, possibly more, that perform different functions.

 

1. The stock core which has had ongoing maintenence and improvement so generally you'll see versions around from 1.22 thru 1.26.

2. There was a VGA core which allowed using a 30 KHz instead of 15 KHz monitor but required a faster crystal (?) and was GTIA only (?)

3. The GTIA only core.

4. A sound processor core, unsure if it went further than proto stage or had any general release - reassigns output bits and turns VBXE into a digital sound processor.

Ok, so, if someone just orders a VBXE off Lotharek’s site today, they’re getting #1. Gotcha.

 

Link to comment
Share on other sites

26 minutes ago, bfollowell said:

Ok, so, if someone just orders a VBXE off Lotharek’s site today, they’re getting #1. Gotcha.

There are several core slots and you can use the supplied 'FC.COM' core flasher to select the boot core (from a pre-installed selection of several cores, including the GTIA core and versions with and without 320K RAM upgrade emulation) or flash other cores to the slots. The VGA core is completely deprecated; not sure of the status of the audio core.

 

The latest FX core (without PORTB RAM upgrade emulation) is active on a newly purchased board, but you need simply download FC.COM to activate whichever core you want. The problem appears to be that all cores share the same palette (assuming the palette is even integral to each individual core package, which I do not know).

 

Link to comment
Share on other sites

12 minutes ago, flashjazzcat said:

There are several core slots and you can use the supplied 'FC.COM' core flasher to select the boot core (from a pre-installed selection of several cores, including the GTIA core and versions with and without 320K RAM upgrade emulation) or flash other cores to the slots. The VGA core is completely deprecated; not sure of the status of the audio core.

 

The latest FX core (without PORTB RAM upgrade emulation) is active on a newly purchased board, but you need simply download FC.COM to activate whichever core you want. The problem appears to be that all cores share the same palette (assuming the palette is even integral to each individual core package, which I do not know).

 

OK, thanks flashjazzcat. I think it's clear now. We order VBXE, or VBXL from Lotharek, we're all getting the same units, assuming no rev3 coming soon or anything. Then we could have any of the four types at any given time, depending on which core we flash to, and we can use the core flasher tool to do that with.

 

OK, then, it doesn't seem like it would be hard at all to create an NTSC core, and that is just one of the available cores we could flash with. If the only thing different is the color palette, it seems like it would be easy to modify that core with every new revision as well. Of course, I realize  me sitting here saying, "It doesn't seem like it would be hard" means absolutely nothing. It's always easy when we're asking someone else to do the work! And I understand why it wasn't done initially. It was created in Europe, Poland if I remember correctly, where they use machines with PAL color palettes. They just create what was "normal" to them and it didn't occur to them that it wouldn't look normal to us NTSC users.

 

Anyway, it's another $100, but I'll probably add a VBXE to my 1088XEL build, just to give me more output options, I've already ordered Cool Novelties special-made Scart cable for it after all, and the added graphic capabilities are pretty cool, but I definitely hope to see an NTSC version of the cores eventually. I'd be willing to bet Lotharek would see more sales of it if one were available.

Link to comment
Share on other sites

The audio core and (I think) the VGA core in fact require a different hardware setup as some of the VBXE hardware IO is reassigned.

I should have mentioned the stock A and R suffixed cores - the Rambo emulation is generally a good idea if you only have a 128K or less machine to start with.

If you have Ram expansion of 320K or more then you generally won't need Rambo emulation by the VBXE as you'd be duplicating something you already have.

Link to comment
Share on other sites

  • 4 months later...

Now that I'm a new VBXE owner, I was wondering if anyone had made further progress on this NTSC palette issue? That is to say, not running a utility from SDX every time the machine boots, but running games and applications in the color scheme those of us blessed to be from the wrong side of the world are used to. :)

Link to comment
Share on other sites

21 minutes ago, DrVenkman said:

Now that I'm a new VBXE owner, I was wondering if anyone had made further progress on this NTSC palette issue? That is to say, not running a utility from SDX every time the machine boots, but running games and applications in the color scheme those of us blessed to be from the wrong side of the world are used to. :)

Nothing that I am aware of unfortunately.

Link to comment
Share on other sites

5 hours ago, DrVenkman said:

Now that I'm a new VBXE owner, I was wondering if anyone had made further progress on this NTSC palette issue?

 

5 hours ago, Stephen said:

Nothing that I am aware of unfortunately.

Without that, you may as well put a disclaimer on the product saying it's only really suitable for PAL.

 

  • Like 1
Link to comment
Share on other sites

I’d love to help with something like that, but it’s definitely outside of my area of expertise. Didn’t someone mention, either earlier in this thread, or in a similar thread, that Altirra has a good NTSC palette? I’m not certain what format it’s in though.

 

Link to comment
Share on other sites

I think from what @phaeron has said, Altirra’s palette is procedurally-generated. He probably would have some good insights though as to what it would take to create a suitably acceptable NTSC palette file. So too would @Trebor, who has done some really excellent work regarding the Atari console color palettes, and @Bryan, too - creator of several Atari video mods and the ACP.XEX test image program many of us use to calibrate our screens. 

Link to comment
Share on other sites

it is really simple, either there will be act file i could convert and recompile core files, or not, and it won't get done

someone has to do it

currently used pallete is called laoo.act and comes from atari800win emulator as it was agreed among users in Poland to be most representative for computers we had, but then another graphics artist came and said he dislike it and wanted his own pallette inside instead

i don't want to argue over shades of blue, red or any other color - i can compile in any palette, but its up to you guys to come up with one that majority agrees on and it is in act file format

this is all i can do

 

  • Like 6
Link to comment
Share on other sites

1 hour ago, bfollowell said:

OK, those of us that are concerned about it will look into options and discuss  amongst ourselves and try to come to an agreement and get you a palette to covert.

 

Maybe a poll with various .act files linked with images could be made?

Link to comment
Share on other sites

Yes, but I doubt candle is going to want to recompile the code every time to take pictures for us to choose from. So, for your suggestion that we'll need to put together a series of different act files that we can try out in an emulator and take screenshots of that to see which we can all agree on, then send the winner to candle.

 

If that's what you meant, I'm sorry for over-simplifying. I just wanted to make certain we were all on the same page.

 

Link to comment
Share on other sites

8 minutes ago, bfollowell said:

Yes, but I doubt candle is going to want to recompile the code every time to take pictures for us to choose from. So, for your suggestion that we'll need to put together a series of different act files that we can try out in an emulator and take screenshots of that to see which we can all agree on, then send the winner to candle.

 

If that's what you meant, I'm sorry for over-simplifying. I just wanted to make certain we were all on the same page.

 

Actually what I meant was loading them up through the methods mentioned ealier, like SDX, maybe take a picture through a capture card. 

Closer to real hardware that way.

  • Like 1
Link to comment
Share on other sites

2 hours ago, leech said:

Actually what I meant was loading them up through the methods mentioned ealier, like SDX, maybe take a picture through a capture card. 

Closer to real hardware that way.

Ok, gotcha. I don’t have mine up and running in my 1088XEL yet, and I do not know how to temporarily load a new palette using the SDX tools, though I do seem to remember seeing them mentioned. We’re leaving for a week in Florida tomorrow, so I’ll be out for a week, but I’ll get my VBXE installed and familiarize myself with manually loading the palettes when I get back so I can maybe help out.

 

Link to comment
Share on other sites

Okay, well as a starter for discussion for NTSC folks, here's what I did. I started up Altirra and used the menus to select its default NTSC colors (View --> Adjust Colors ...). I then exported the palette as a .PAL file. Next I loaded this .PAL palette into Atari800 and then saved it as an .ACT file. I then set Altirra to NTSC + Commodore 1702 monitor. This is much more saturated (maybe too much so) but it's at least an option to consider. I went through the same steps to get an .ACT file. 

 

NTSC Default:

image.thumb.png.7597ed14a8f8fe0923c09dc037ec7f08.png

 

 

NTSC + C1702 Monitor:

image.thumb.png.bb91e9bd24badda0b2b87bbfe1e87fde.png

 

There are several other presets available in Altirra plus infinite adjustability. Personally, I'd be happy with either of the above and I'm not strongly wedded to either. 

 

 

AltirraC1702.act AltirraDefault.act

  • Like 2
Link to comment
Share on other sites

Might consider the 'NTSC Contemporary' profile as an alternative to the C1702 profile. The latter is an older profile that was made before I implemented color primary correction and has a high amount of blue boost to try to make up for it. The NTSC Contemporary profile uses color correction instead and is a bit 'softer'.

 

Also, I would double-check these palettes on an existing VBXE before asking for a new core bake. The palettes are specified in sRGB, but I don't know if anyone has verified that the VBXE RGB output has similar gamma. I'm guessing that it should with a VGA output, but you never know. If there is a gamma discrepancy then a transform will be needed on the color values.

 

  • Like 2
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...