Author Topic: DaDither - new image converter  (Read 4466 times)

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Offline trocoloco

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Re: DaDither - new image converter
« Reply #25 on: 20:59, 02 February 21 »
uest to the owners of real machines: could you check how images look on your monitors?

Hi, I've been testing some images on my 6128 and a CRT TV - Samsung slimfit, for more details.

I have used 70% flickering and even tho you can later reduce the palette on Perfect Pix, for darker colours flickering is barely to noticeable, on the other side when it comes to mixing bright colours, specially when mixing yellow, orange and cyan it is very noticeable. It makes a good effect for neon effects and fires hehe.
But more than a problem of the conversion, I believe is by the contrast of the colours used , which surely can be improved when editing the image.

By the way, will you implement modes B1 and R also? It would be a nice feature.

All in all, every image worked great and it does a nice job IMO. Thanks for this nice program :)

Offline Dec

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Re: DaDither - new image converter
« Reply #26 on: 22:33, 02 February 21 »
I've been testing some images
What palette did you use? sRGB or RGB? Did you test Gray mode?

when it comes to mixing bright colours ... it is very noticeable
You can try to reduce flickering by reducing Max flickering parameter.

But more than a problem of the conversion, I believe is by the contrast of the colours used
Could you explain what do you mean?

will you implement modes B1 and R also?
B1 - no, I don`t see a way how to automatically convert images into this mode. R - I am studying it now.

Offline trocoloco

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Re: DaDither - new image converter
« Reply #27 on: 23:58, 02 February 21 »
What palette did you use? sRGB or RGB? Did you test Gray mode?
RGB palette is more accurate for CPC when converting images. Regarding the gray mode, I don't see the point of gray mode with regular CPC palette, but sure suits plus models.

But more than a problem of the conversion, I believe is by the contrast of the colours used
Could you explain what do you mean?

when mixing for example yellow and pink the blinking is more visible because difference of color values , than mixing red and brow for example.

Offline Dec

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Re: DaDither - new image converter
« Reply #28 on: 03:27, 03 February 21 »
trocoloco, could you also test 2 images from the attachment. I am interesting in flickering level of images.

Offline Dec

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Re: DaDither - new image converter
« Reply #29 on: 06:41, 03 February 21 »
Update: Mode 2 512x256x1 support added (HGB files)

Offline ComSoft6128

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Re: DaDither - new image converter
« Reply #30 on: 08:33, 03 February 21 »
Hi @Dec , thank you for creating such an excellent tool, I have a question which is for CPCWiki members.


I've saved a converted file (.scr) to my downloads folder - how do I get this into a .dsk file for loading into the VIDI Rom or Advanced Art Studio?

Offline Dec

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Re: DaDither - new image converter
« Reply #31 on: 09:11, 03 February 21 »
how do I get this into a .dsk file
I used ManageDsk tool to create DSK disk images.

Offline ComSoft6128

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Re: DaDither - new image converter
« Reply #32 on: 10:36, 03 February 21 »
Thanks @Dec  :)

Original:


Offline ComSoft6128

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Re: DaDither - new image converter
« Reply #33 on: 10:39, 03 February 21 »
CPC version:


https://www.youtube.com/watch?v=TvzrHkQW43k


Please note that the VIDI Rom only and not the hardware unit was used in the making of the video.

Links:
https://www.cpcwiki.eu/index.php/VIDI_digitizer


https://cpcrulez.fr/hardware-digit-digitaliseur_vidi.htm?t=VQ==


Not emulated - original hardware and software.

Please note that  the aspect ratio for this YouTube video is 16:9 but the CPC monitor
has an aspect ratio of 4:3 so you may wish to adjust your viewing device accordingly.
« Last Edit: 11:09, 03 February 21 by ComSoft6128 »

Offline trocoloco

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Re: DaDither - new image converter
« Reply #34 on: 17:02, 03 February 21 »
trocoloco, could you also test 2 images from the attachment. I am interesting in flickering level of images.


for Test full screen is white mixed with some other colour and Test2 the full screen goes mauve or so as it uses yellow and pink or fucsia. The screens doesn't seem to flicker much but as everything is the same colour there's no other colours to compare with.

Offline ComSoft6128

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Re: DaDither - new image converter
« Reply #35 on: 17:29, 03 February 21 »
Converted file loaded into the Advanced Art Studio.

Original



Offline ComSoft6128

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Re: DaDither - new image converter
« Reply #36 on: 17:30, 03 February 21 »
Mode 2 CPC file



https://www.youtube.com/watch?v=BRHYIvWrmpU



Not emulated - original hardware and software.


Please note that  the aspect ratio for this YouTube video is 16:9 but the CPC monitor
has an aspect ratio of 4:3 so you may wish to adjust your viewing device accordingly.

« Last Edit: 18:03, 03 February 21 by ComSoft6128 »

Offline GUNHED

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Re: DaDither - new image converter
« Reply #37 on: 17:57, 03 February 21 »
Update: Mode 2 512x256x1 support added (HGB files)


Awesome! I will have a look at it right now.  :) :) :)
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Offline GUNHED

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Re: DaDither - new image converter
« Reply #38 on: 00:48, 04 February 21 »
The *.HGB generator (512x256, monochrome) works like a charm! Thank you very much!!!  :) :) :)

However, you can leave the 128 bytes header away. The *.HBG files are only pure GFX data and this way they are exactly 16 KB in size.
One can cut the first 128 bytes off by hand with an hex editor of course too.
But it's just not needed to add the usual header in this case.


Thanks again, this is a great application.  :) :) :)
« Last Edit: 00:59, 04 February 21 by GUNHED »
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Offline Dec

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Re: DaDither - new image converter
« Reply #39 on: 01:54, 04 February 21 »
However, you can leave the 128 bytes header away.
Fixed. Now tool creates file without AMSDos header. But there is an option that allows user to add header if it is needed.

Offline Dec

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Re: DaDither - new image converter
« Reply #40 on: 02:38, 04 February 21 »
for Test full screen is white mixed with some other colour
White is mixed with black and resulting color must be gray.

The screens doesn't seem to flicker much.
So we have a screen with most dark and most bright mixed colors and there is weak flickering. The feeling of flickering depends on how pixel with different colors are arranged on the two screens. My tool tries to minimize flickering by keeping the total brightness of both screens at the same level. The tool has a preview mode for two changing screens (Menu\View\Show flickering image, non CRT monitors will show inaccurate colors) and I don't see flickering on my 60 Hz monitor at all. And in my opinion, if you see large flickering, the tool has incorrectly placed the pixels on the screens, and this is due to the fact that the colors in used palette do not correspond to the real colors on your monitor.

So the main question is What are the correct RGB values for the Amstrad CPC palette. I really don`t understand why in all articles about Amstrad CPC palette it is recommended to use 127/128 for gray. Because real middle between black and whlite is 188.

Offline trocoloco

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Re: DaDither - new image converter
« Reply #41 on: 11:16, 04 February 21 »
White is mixed with black and resulting color must be gray.
is gray-ish- , certaninly it looks more white than black, not a 50/50 mix but will check and change a bit contrast and bright on the TV and see how this goes.

My tool tries to minimize flickering by keeping the total brightness of both screens at the same level. The tool has a preview mode for two changing screens (Menu\View\Show flickering image, non CRT monitors will show inaccurate colors) and I don't see flickering on my 60 Hz monitor at all. And in my opinion, if you see large flickering, the tool has incorrectly placed the pixels on the screens, and this is due to the fact that the colors in used palette do not correspond to the real colors on your monitor.

Remember that CPC refreshes at 50hz not 60 so effect won't be seen the same way. Using the Show flickering option, I have noticed (at least in my 60hz monitor) that noticeable flickering occurs between around 35 and 85 , at 100% flickering is gone. So, what i will try is a couple of picture in various in from 0 to 10 in 10% increments and see how it responds.

for reference I will use these pictures



« Last Edit: 11:26, 04 February 21 by trocoloco »

Offline Sykobee (Briggsy)

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Re: DaDither - new image converter
« Reply #42 on: 11:30, 04 February 21 »

(I was responding to a comment that seems to have been deleted)

The gate array RGB voltages probably don't correspond to how the CPC monitor displays the eventual colour as there's likely some curve (so it's certainly possible that grey would be closer to 70% than exactly 50% grey). Also there might be variance between ASIC versions.


The best solution would be to properly record the on-screen colours using a screen calibration tool into some known colour space (sRGB, etc) so they can be used in tools like this, and emulators.


Also it's possible that the first CPC emulators, which picked 127, were displayed on CRT monitors themselves, so this worked fine and was fairly accurate.
« Last Edit: 11:32, 04 February 21 by Sykobee (Briggsy) »

Offline Dec

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Re: DaDither - new image converter
« Reply #43 on: 12:06, 04 February 21 »
I have noticed (at least in my 60hz monitor) that noticeable flickering occurs between around 35 and 85
There was a serious error in my algo. Thanks to your notice I fixed it. Thanks! Please update the program.

Offline Dec

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Re: DaDither - new image converter
« Reply #44 on: 12:19, 04 February 21 »
The gate array RGB voltages probably don't correspond to how the CPC monitor displays the eventual colour as there's likely some curve
So we need a specialist who understands how CRT monitor works inside.

The best solution would be to properly record the on-screen colours using a screen calibration tool into some known colour space (sRGB, etc) so they can be used in tools like this, and emulators.
Fully agree.

Offline Dec

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Re: DaDither - new image converter
« Reply #45 on: 12:31, 04 February 21 »
And my error again  :doh: Actual version is 1.36.

Offline GUNHED

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Re: DaDither - new image converter
« Reply #46 on: 17:43, 04 February 21 »
Windows 7, 64 bit: Started DaDither, loaded flor.jpg (see before). Program suddenly ended.
Tried again, works well, including saving picture.


The headerless feature works perfect for .HGB wallpapers - Thank you very much!



« Last Edit: 17:50, 04 February 21 by GUNHED »
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Offline trocoloco

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Re: DaDither - new image converter
« Reply #47 on: 23:09, 04 February 21 »
Hi @Dec , i have been testing the flower pic in various degrees of flickering tolerance and obviously 0% didn't flicker as it was 16 cpc colours, then as percentage increases so does the flickering. As said more in bright colurs, first it was the lower band of petals where the fucsia and blues are mixed and then from 60% 70% onwardsthe flickering increases yellow and white colours but.

All in all the flickering is less noticeable and unpleasant to the eyes,  is the normal flicker effect that it is expected with this type of technique. IMO it has improved over the previous test. I have to say that i used RGB palette, I will do more tests using sRGB instead.

Before i had to suffer to create screens in such format but thanks to you, now is piece of cake!

Offline Dec

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Re: DaDither - new image converter
« Reply #48 on: 19:11, 08 February 21 »
All in all the flickering is less noticeable and unpleasant to the eyes

I have found another one bug in my anti flickering algo. Could you check updated version?

Updated version also has limited B1 support.

Offline trocoloco

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Re: DaDither - new image converter
« Reply #49 on: 21:52, 08 February 21 »
I have found another one bug in my anti flickering algo. Could you check updated version?

Updated version also has limited B1 support.

Hi! yes no problem, I will run some tests and let you know tomorrow what I've found out  :)