| |
spinal
Account closed
Registered: Jan 2005
Posts: 47 |
converting graphics...
I've started a GFX converter, just for fun.
I started by calculating the possible colors mixable from a fairly accurate C64 palette, and came up with the following 135 color palette (including the origional 16 C64 colors).
Using it, I did an RGB comparison to the 135 colors, an plotted the two colors which compose the mixed color on odd or even lines, ie, if the line being drawn was even, then color 1 was plotted, if odd, color 2. The result follows...
I have yet to do lo-res color reduction(3+background), but there is plenty of time for that.
I was wondering if anyone can offer advice for better quality output, I read in another post, that a luminosity check should be done first, then an RGB check (I assume only checking close luma values), I gave that a go first, but ended up with a very similar output. |
|
... 27 posts hidden. Click here to view all posts....
|
| |
Oswald
Registered: Apr 2002
Posts: 5127 |
anyhow YUV or RGB converter, the best result will only come if a gfxer retouches about every pixel in a converted pic. So searching for the ultimate converter is like the search for the holy grail.
converting from 24 bit to 8 bit paletted, and dithering, and fancy stuff makes sense.
converting from 24bit to 4 bit fixed colors will never make much sense :)
imho |
| |
A Life in Hell
Account closed
Registered: May 2002
Posts: 204 |
Quote: anyhow YUV or RGB converter, the best result will only come if a gfxer retouches about every pixel in a converted pic. So searching for the ultimate converter is like the search for the holy grail.
converting from 24 bit to 8 bit paletted, and dithering, and fancy stuff makes sense.
converting from 24bit to 4 bit fixed colors will never make much sense :)
imho
Isn't doing something for the technical challenge of it enough? |
| |
Oswald
Registered: Apr 2002
Posts: 5127 |
for some yes for some not :) |
| |
Oswald
Registered: Apr 2002
Posts: 5127 |
just did some tests with the picture posted here, in my editor p1. without any tweaking it got the picture uglyer, but tweaking contrast and gamma made wonders.
maybe an ultimate algorithm should somehow autoadjust those. trying to get close those colors that are most used to the c64 palette. |
| |
Credo
Registered: Sep 2002
Posts: 11 |
ALiH: It may be a trivial question and a bit offtopic here, but what is the real C64 pixel aspect ratio (you wrote: "and of coruse it fixes aspect ratio so will look squished on vice")?
After Googling for the answer for 1-2 years, I even tried to measure the size of the between borders area on my 14 col TV with a tape, but I guess that was far from being accurate, so I skipped the idea. I guess the most accurate (but far from being 100% accurate) numbers can be measured on an official Commodore monitor which I don't have.
With the exact aspect ratio in hand even VICE could be stretched to a correct aspect ratio with a software or hardware (rendering into a texture) method (of course some subpixel boundaries would be crossed here and there, but maybe the correct aspect ratio would worth it). |
| |
chatGPZ
Registered: Dec 2001
Posts: 11523 |
me and seven worked that out exactly some time ago....however i forgot the exact numbers :=D maybe seven remembers it.... |
| |
spinal
Account closed
Registered: Jan 2005
Posts: 47 |
surely switching to full screen with a responsible screen res (perhaps 400*300) would defeat the point of needing to know? |
| |
Krill
Registered: Apr 2002
Posts: 3098 |
i might thinking too simple, but isn't 404/312 (~1.29:1) a good estimate for pal screens? maybe subtract a few lines from 312 for invisible pal lines, though. |
| |
A Life in Hell
Account closed
Registered: May 2002
Posts: 204 |
Quote: ALiH: It may be a trivial question and a bit offtopic here, but what is the real C64 pixel aspect ratio (you wrote: "and of coruse it fixes aspect ratio so will look squished on vice")?
After Googling for the answer for 1-2 years, I even tried to measure the size of the between borders area on my 14 col TV with a tape, but I guess that was far from being accurate, so I skipped the idea. I guess the most accurate (but far from being 100% accurate) numbers can be measured on an official Commodore monitor which I don't have.
With the exact aspect ratio in hand even VICE could be stretched to a correct aspect ratio with a software or hardware (rendering into a texture) method (of course some subpixel boundaries would be crossed here and there, but maybe the correct aspect ratio would worth it).
I'm using 1.2x stretched vs. a pc monitor (576(/2) visible lines on a PAL c64 vs. 480 lines on a "normal" vga in its low resolution mode), however this is possibly not _entirely_ accurate - I just guessed at something that "looks right". |
| |
Oswald
Registered: Apr 2002
Posts: 5127 |
in usual 'oswald' style I think of the ratio problem that it's unimportant to consider so strictly, no one's brain will ever notice a small difference imho, unless its _put_beside_ another ratio or you see the two different ratio screens with a small time gap.
Human vision greatly compensates for that. There were experiments where humans had to wear 24h glasses that turned the picture upside down, they got used to it in days, in fact their brain turned the picture back.
a personal experience: Back in the early 80's I saw TV broadcasts where they stretched vertically the originally widescreen movie to cover the top/bottom black area. After watching a movie like that for half an hour, you forgot about it, and felt like the picture has normal dimensions, and normal aspect ratio broadcasts looked off aspect.
|
| Previous - 1 | 2 | 3 | 4 - Next |
