Blarrg NTSC filter with VICE emulator

Discussion of development of software for any "obsolete" computer or video game system. See the WSdev wiki and ObscureDev wiki for more information on certain platforms.
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Individualised
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Blarrg NTSC filter with VICE emulator

Post by Individualised »

Is there any way I can use the Blarrg NTSC filter with VICE? I'm not really a fan of the default CRT filter VICE uses (frankly it looks nothing like a CRT display and gives me a headache; sorry VICE devs). I'm looking to emulate this appearance:
Image
(edit: wrong sub-forum, meant to post in General Stuff)
lidnariq
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Re: Blarrg NTSC filter with VICE emulator

Post by lidnariq »

Blargg's filters - he only wrote ones for the NES, SNES, and SMS - are all based around the same core of taking three pixels (or 6 for when the SNES emits 512px) and generating 7 out. This is because 3 NES/SMS pixels are 2 colorburst cycles, and so things line up into a small operation that can be done repeatedly.

Unfortunately, the NTSC C64's pixels are not a nice ratio relative to colorburst - 16 pixels correspond to 7 colorburst cycles.

Blargg's web site does state that he'd be willing to at least look into making one for the C64 - just email him.
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Individualised
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Re: Blarrg NTSC filter with VICE emulator

Post by Individualised »

lidnariq wrote: Mon Mar 20, 2023 11:01 am Blargg's filters - he only wrote ones for the NES, SNES, and SMS - are all based around the same core of taking three pixels (or 6 for when the SNES emits 512px) and generating 7 out. This is because 3 NES/SMS pixels are 2 colorburst cycles, and so things line up into a small operation that can be done repeatedly.

Unfortunately, the NTSC C64's pixels are not a nice ratio relative to colorburst - 16 pixels correspond to 7 colorburst cycles.

Blargg's web site does state that he'd be willing to at least look into making one for the C64 - just email him.
I honestly didn't realise they were specific for each platform. That makes a lot more sense. Thank you.
Pokun
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Re: Blarrg NTSC filter with VICE emulator

Post by Pokun »

Mesen 2 seems to have expanded Blarg's filter for PC-Engine and Game Boy (where it doesn't make sense unless in SGB mode) as well, but no C64 of course.

Doesn't C64 support S-video (or something very close to S-video despite predating it)? To emulate that, it would need a CRT filter without the NTSC color artifacts. I guess same goes for its monochrome mode.
If not text might be hard to read.
ap9
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Re: Blarrg NTSC filter with VICE emulator

Post by ap9 »

Pokun wrote: Tue Mar 21, 2023 2:30 pm Doesn't C64 support S-video (or something very close to S-video despite predating it)? To emulate that, it would need a CRT filter without the NTSC color artifacts. I guess same goes for its monochrome mode.
If not text might be hard to read.
blargg's filter is customizable on the degree of artifacting, sharpness, etc. and carries an S-Video profile. Since the VICE renderer works on YIQ/YUV values, the code could theoretically be modified to pass values through the blargg filter.
Pokun
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Re: Blarrg NTSC filter with VICE emulator

Post by Pokun »

I see, Blarg's filter should be perfect then.
Drag
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Re: Blarrg NTSC filter with VICE emulator

Post by Drag »

Pokun wrote: Tue Mar 21, 2023 2:30 pm Doesn't C64 support S-video (or something very close to S-video despite predating it)? To emulate that, it would need a CRT filter without the NTSC color artifacts. I guess same goes for its monochrome mode.
If not text might be hard to read.
The VIC-II chip outputs separate luma and chroma signals, so you have two video cables instead of one. The main difference would be that there's no crosstalk between luma and chroma (so, less fringing on the edges of text), but there's still some artifacts with C64 video itself, such as jailbars (I grew up with a C128 and it had *heavy* jailbars), and a slight delay on the chroma signal (i.e., color looks slightly blurry).

And of course, the usual fun thing of nobody quite agreeing on what the "most accurate" VIC-II palette is, just like us! Also because the VIC-II's palette is slightly different from chip revision to chip revision, also like us! :D
Pokun
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Re: Blarrg NTSC filter with VICE emulator

Post by Pokun »

I see, thanks for explaining.
I meant specifically NTSC color artifacts, not just fringes but actual colors of certain pixels that are not generated by the video chip but is still interpreted like so by the TV due to how composite signal mixes the luma and chroma signals. I suppose that's part of the luma and chroma cross-talk as I never see such things in S-video signals.
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Re: Blarrg NTSC filter with VICE emulator

Post by Individualised »

Drag wrote: Sat Mar 25, 2023 12:56 pm And of course, the usual fun thing of nobody quite agreeing on what the "most accurate" VIC-II palette is, just like us! Also because the VIC-II's palette is slightly different from chip revision to chip revision, also like us! :D
I saw that VICE had different palette options for the C64 and VIC-20 and knew there had to be a similar situation to the NES for those systems too.
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