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pepto
Account closed
Registered: Nov 2004
Posts: 35 |
colodore is the new pepto
Hey guys, I remeasured the video-signals of my VIC-II's and slightly updated my 15 year old attempt at calculating an rgb-clone. While at it, I also measured VIC & TED and made a little website about it, that allows you to adjust brightness, contrast and saturation as you like and then save your own custom palette to a png-file.
http://www.colodore.com
I took extra care to make sure, that the brightness, contrast and saturation sliders behave the same way as my 1084s.
While closely comparing my LCD to the 1084s, I found that making the transparency of scanlines dependent on YUV's Y (so they are less visible for brighter colors) looked a lot more like the real thing. I also noticed that the phase-shift on odd-lines happens for YUV's V only and there's even a name for it in video-lingua: hanover bars.
After implementing this, I'm happy to say that the images on my LCD and 1084s are remarkably close.
I will write a more detailed article about it in January, but seriously need a christmas-break first...
Cheers,
pepto |
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JackAsser
Registered: Jun 2002
Posts: 1989 |
Quote: mmmh somehow i expected some more details =)
Maybe you think it's more complicated than it really is? :D |
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chatGPZ
Registered: Dec 2001
Posts: 11108 |
perhaps =) |
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pepto
Account closed
Registered: Nov 2004
Posts: 35 |
Well, where I come from, simple solutions are actually preferred, as long as they get the job done (see "KISS principle"). :D
I kinda like how little code is needed for a convincing result. In fact, I spent extra time rearranging it, for more clarity.
This means, that more xplat-tools could incorporate brightness, contrast and saturation sliders in the future - in a painless way... \o/ |
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pepto
Account closed
Registered: Nov 2004
Posts: 35 |
Quoting LogicDeLuxeAnd for further taking different monitor behaviors into account, I guess, gamma sliders for YUV and also for RGB would make sense.
Furthermore, sliders for offset and gain for YUV and RGB. Those advanced settings can be hidden in a "service menu", like it was the case in most CRT TVs since the mid 90's.
Hmm, I never came across CRTs with Gamma, Offset and Gain dials. I will think about adding "advanced" settings to colodore.com though - thanks for feedback. |
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soci
Registered: Sep 2003
Posts: 473 |
Just a few more steps and there will be separate RGB sliders for each colour for maximum flexibility ;) |
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chatGPZ
Registered: Dec 2001
Posts: 11108 |
i'd be most interested in seeing the algorithm applied to NTSC (using the sony decoder matrix).....
did a quick test in VICE with the hannover bars stuff as you implemented them.... now everything is pink. knoekicolors =) i think the renderer cant be reused as is and must be rewritten. sux ;_; |
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pepto
Account closed
Registered: Nov 2004
Posts: 35 |
Quoting Groepazi'd be most interested in seeing the algorithm applied to NTSC (using the sony decoder matrix).....
If I didn't f*ck it up, like this I guess (only tested in Chrome): http://www.pepto.de/groepaz.html |
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chatGPZ
Registered: Dec 2001
Posts: 11108 |
hard to tell (for me anyway) without a test picture and CRT emulation attached.... but thanks :) (incase you want to add some pictures for ntsc, check the work of DocJM - awesome stuff. and pics like this can tell you if you got the aspect ratio right :)
oh and i almost forgot, i have a feature request.... could you add an option to download the palette in VICE format? converting them by hand is a bit annoying =) |
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ilesj
Registered: Jun 2012
Posts: 27 |
Btw why the delay line doesn't seem to have any effect on the hanover bars? |
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pepto
Account closed
Registered: Nov 2004
Posts: 35 |
Quote: Btw why the delay line doesn't seem to have any effect on the hanover bars?
Good question, I'm wondering this myself... looking at the output though, both effects are definitely present. Chroma blending with the previous line, and phase-shift for the v-component. |
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