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Picodrive 1.80


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#31 notaz

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Posted 21 September 2010 - 09:16 PM

Ok I took my time and plugged my MegaDrive to a TV card. I'd love to make use of RGB capture card instead but those are prohibitively expensive.
Posted Image

Here is framebuffer dump directly from pandora:
Posted Image

Older build:
Posted Image
It looks darker on pandora itself but that's a problem with it's LCD and the LCD gamma should be tuned further instead.

Your comparison again, for reference:

Posted Image


Except of seeing that both old and new builds are wrong (that makes all PC emus wrong too I guess) I don't really know how to calibrate this. The reference image heavily depends on TV card settings. I haven't seen anyone doing RGB captures from the real thing either. The old build might look better to you but it's levels are wrong compared to levels of pixels with shadow/hilight operators applied.

#32 TitanUranus

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Posted 21 September 2010 - 09:49 PM

Ok I took my time and plugged my MegaDrive to a TV card.


Wow, Lithuania has real megadrives! Personally I'd just leave it as it is for now - spend your time productively on coding rather than arseing around with megadrives and TV cards on some wild goose chase for a perceptual pinnacle of accuracy that can never be achieved. Refine it later when you have finished all other stuff you want to do, maybe some time in your extreme old age, shortly after you've taken up bunjee-jumping and developed a crack addiction. For now concentrate on doing what makes you happy today.

Edited by TitanUranus, 21 September 2010 - 09:49 PM.


#33 notaz

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Posted 21 September 2010 - 10:09 PM

Wow, Lithuania has real megadrives!

Sure, it was very popular here (it never surpassed NES clones though) and I (mis)spent good portion of my childhood playing one. That's the main reason I work on PicoDrive these days.

#34 EvilDragon

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Posted 21 September 2010 - 10:12 PM

Well, I'd like to help here, since I love as most accurate emulation as possible, too.

We got some TV Gamma LCD setting in the Pandora already (it's not the default setting) where I tried to be more close to a real TV.
It wasn't an accurate measuring, just a subjective one based on the color bars, but it looks okay for me with most emulators and it looks more like notaz' recorded screenshot from the actual MegaDrive, so we're not that far off.

To make the LCD gamma more like a TV gamma, I could use proper tools (got a couple of waveforms, vectorscopes and calibrated monitors at work) if I could have the same picture that the Pandora displays when using the gamma tool,
I will then create an LCD gamma that matches as closely as possible to a real matched CRT.

When that is done, I could help making the MegaDrive gamut correct... though I'd need a version of PicoDrive where I can change the gamma values. I would then report back the proper values.
They would only work properly when using the TV Gamma settings in LCD Manager though.

#35 TitanUranus

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Posted 22 September 2010 - 01:04 AM

What a bunch of geeky nutters Pandora has managed to assemble. I am proud to consider myself among them. Though Evildragon, forgive me for asking this, but will you be farting around with those fancy toys (vectorscopes/calibrated monitors etc...) in your spare time? Or has the pinpoint perfection of a megadrive colour pallete become a high priority in these busy times?

#36 Esn

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Posted 22 September 2010 - 01:35 AM

Notaz, I think it's awesome that you took heed of DaveC's comment and compared it yourself. Thanks!

#37 jonlad1

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Posted 22 September 2010 - 02:18 AM

I haven't gotten complaints (actually haven't gotten any comments at all strangely enough)



Maybe if you released Temper to us Pandorians we could pass on some comments ;) (hint hint)

#38 DaveC

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Posted 22 September 2010 - 02:40 AM

Ok I took my time and plugged my MegaDrive to a TV card. I'd love to make use of RGB capture card instead but those are prohibitively expensive.
Posted Image

Your comparison again, for reference:


Posted Image


Except of seeing that both old and new builds are wrong (that makes all PC emus wrong too I guess) I don't really know how to calibrate this. The reference image heavily depends on TV card settings. I haven't seen anyone doing RGB captures from the real thing either. The old build might look better to you but it's levels are wrong compared to levels of pixels with shadow/hilight operators applied.

Well the newest build looks the darkest of the lot, and futher from the top picture than the rest. The previous one at least had the shades a bit closer and you could see the brown on the rocks better, but they are close to the same. The frame dumps have the shadow detail crushed too. Even that purple bar at the top is almost pulled to black. The text for the score has a bright spot in the center but then falls off to the point you can't see the edges. It is not just a dark LCD as you say or ALL shades would be dark together, but smooth. If you look at the rocks in the example the tan highlights are as bright as the other builds/example but the shadow detail is crushed. This is because the gamma curve is suppressing darker shades for some reason.

In the example I did I tuned the colors on the second image in a paint program to match how they look on the actual LCD, not a frame dump as that looks a bit different. Try it on your Pandora unless you have custom settings it pretty much looks like my second pic(I just checked again). I have the LCD gamma as default which is just a linear ramp. I have the brightness set to one notch below the brightest. Yes I can tune the LCD gamma to improve but then it will screw up all of the other software that doesn't need a gamma change. I don't know if it is possible for the emulator to read Pandora custom gamma settings. Even some kind of script that loads a setting then returns it back after you exit would work.

I am not sure why you say the older one was more "wrong" when it looks better. It looks like what the shadow operator does is get rid of shadow detail. I am not sure how that is better, that looks more different than your first pic (although I admit is a bit TOO washed out). The top image doesn't crush shadow detail like the Pandora build does (used the rocks, score text again as example).

If I did do an LCD gamma tweak so that it looks better could you use those numbers for your table? I know you couldn't do it directly but maybe they could be used as a reference?

Edited by DaveC, 22 September 2010 - 03:32 AM.


#39 TitanUranus

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Posted 22 September 2010 - 03:06 AM

...


I'm impressed at your restraint this time DaveC, thought you might request Notaz disassemble his real megadrive and reassemble it with some modified componentss that don't blur the screen so much! Just kidding, please don't take it personally.

Edited by TitanUranus, 22 September 2010 - 03:08 AM.


#40 sebt3

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Posted 22 September 2010 - 03:47 AM

^^ You just don't understand...
DaveC didn't force notaz to plug his megadrive. Notaz is still free of will : he don't charge a penny for this :)
Try to see it the other way around : once your software is DaveC compliant, it will please anyone around. Thus making his comments valuable as it somewhat drive the quality of the software on the scene...

#41 notaz

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Posted 22 September 2010 - 08:47 AM

In the example I did I tuned the colors on the second image in a paint program to match how they look on the actual LCD, not a frame dump as that looks a bit different. Try it on your Pandora unless you have custom settings it pretty much looks like my second pic(I just checked again). I have the LCD gamma as default which is just a linear ramp.

The thing is frame dumps should look exactly the same on pandora's LCD as they look on your (assumingly calibrated) monitor, as (mostly) the same data is sent sent to pandora's LCD and your PC monitor when you view those images. The fact that it looks darker on pandora's LCD means it's gamma is miscalibrated.

I have the brightness set to one notch below the brightest. Yes I can tune the LCD gamma to improve but then it will screw up all of the other software that doesn't need a gamma change.

I don't really think so, it is still wrong on the low side at least.

I am not sure why you say the older one was more "wrong" when it looks better. It looks like what the shadow operator does is get rid of shadow detail. I am not sure how that is better, that looks more different than your first pic (although I admit is a bit TOO washed out). The top image doesn't crush shadow detail like the Pandora build does (used the rocks, score text again as example).

It's all about completely different test, Castlevania doesn't use shadow/hilight mode (edit: in that level, IIRC id does use it later in game).

#42 kmob

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Posted 22 September 2010 - 09:03 AM

Would it be perhaps possible to have the gamma tables loaded at start up from a file and thus have them user configurable? That way they could be tweaked to each users' needs and Notaz can move on :).

As it seems we're actually discussing emulation accuracy vs. ascetics.

#43 Nupfi

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Posted 22 September 2010 - 01:28 PM

Just wanted to say thank you for this awesome update! :)
Fullscreen looks incredible... thx!

#44 notaz

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Posted 22 September 2010 - 01:55 PM

Would it be perhaps possible to have the gamma tables loaded at start up from a file and thus have them user configurable? That way they could be tweaked to each users' needs and Notaz can move on :) .

Yup that seems to be a good idea.

#45 geise69

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Posted 22 September 2010 - 04:03 PM

What about the old "Gamma correction" and A_SN's gamma curve options? Those aren't in there anymore, at least not in the Wiz version.(sorry I don't own a pandora) Would that help at all? Do GP2X owners have this issue on their LCD screens? I tried version 1.51 for gp2x in Ginge and then 1.56. Last I loaded 1.80 and didn't notice a difference. Again it could be because of the OLED screen.