Scaler

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Grabulosaure
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Re: Scaler

Postby Grabulosaure » Fri Dec 07, 2018 12:31 am

Sorgelig wrote:can you release this patch?
That would be good for new release with fixed VSync.


Posted.

There is a WIP pipelined divider for the "phase accumulator" mode which now calculates correct interpolation (previously it used a multiplication by 1/SIZE which wasn't quite precise enough and got timing violations). The goal is to eventually get rid of the "delta" signals.

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Re: Scaler

Postby HeroOfTheDay » Fri Dec 07, 2018 5:35 am

Sorgelig wrote:Genesis.zip
Those who have problem with last Genesis release, please try this one.

I've made VSync the same way as in VIP. May be it will fix the problem.


This fixed it for me on my 4k Samsung TV as well. Now just the NES and SNES that aren't working since the latest updates.

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Re: Scaler

Postby jim150 » Fri Dec 07, 2018 7:25 am

Sorgelig wrote:Genesis.zip
Those who have problem with last Genesis release, please try this one.

I've made VSync the same way as in VIP. May be it will fix the problem.


Yes this core works perfectly on my previously affected Sony TV. Thanks for your time and your effort!

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Re: Scaler

Postby Sorgelig » Fri Dec 07, 2018 8:43 am

Ok. I see the problem has been fixed.

I've posted official Genesis release. Any further discussion should move to Genesis and other cores threads.

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Re: Scaler

Postby Sorgelig » Fri Dec 07, 2018 2:04 pm

Grabulosaure wrote:There is a WIP pipelined divider for the "phase accumulator" mode which now calculates correct interpolation (previously it used a multiplication by 1/SIZE which wasn't quite precise enough and got timing violations). The goal is to eventually get rid of the "delta" signals.

In Genesis on Sonic 1 white screen with blue SEGA logo when using LCD effect coefficients you can see some vertical pale stripes. This is a believe result of rounding. Do you mean this problem?
VIP scaler has no such stripes.

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Re: Scaler

Postby ghogan42 » Fri Dec 07, 2018 4:24 pm

Sorgelig wrote:
Grabulosaure wrote:There is a WIP pipelined divider for the "phase accumulator" mode which now calculates correct interpolation (previously it used a multiplication by 1/SIZE which wasn't quite precise enough and got timing violations). The goal is to eventually get rid of the "delta" signals.

In Genesis on Sonic 1 white screen with blue SEGA logo when using LCD effect coefficients you can see some vertical pale stripes. This is a believe result of rounding. Do you mean this problem?
VIP scaler has no such stripes.


This can not be fixed unless an integer scale is forced for horz. and vert. scaling. Maybe when MiSTer 2 supprts 4k TVs. :)

In his test builds, had 3 different "Poly methods": Poly, Poly Rounding Poly PhaseAcc. Each method had very minor differences in when you use dark scanlines or the LCD effect. I don't know which is the best (least rounding errors), but I'm not sure it matters because you can't get perfect results anyway (without perfect integer scaling).

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Re: Scaler

Postby Gamepimp » Fri Dec 07, 2018 4:37 pm

My issue with the top of the image (and apparently the bottom of it based off of the 240p test suite grid pattern) being cut off was fixed by changing the "Picture Size" option on my Samsung TV. There were 4 options: 16:9, Zoom, 4:3, and Custom. I had to choose "Custom" for the entire image to display (which is set to 4:3 in the core).

Unfortunately once I did that, I noticed some scanlines appeared darker while others appeared lighter when there was movement in the game. It created what looked like horizontal bands across the screen. I played around with the resolution settings in the config file as well as the vscale_integer value. The best image I was able to obtain (clean scanlines) while filling most of the screen vertically was to set the resolution to 720p (1280x720@60) and to set vscale_integer to 1.

Sorgelig
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Re: Scaler

Postby Sorgelig » Fri Dec 07, 2018 4:39 pm

ghogan42 wrote:This can not be fixed unless an integer scale is forced for horz. and vert. scaling.

you didn't read my message carefully. I've wrote that VIP scaler has no such artifacts and it's not scaled by integer. Check the Genesis_20181126.
So it has nothing to do with integer scaling. It's simply an error accumulation in interpolation.

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Re: Scaler

Postby Sorgelig » Fri Dec 07, 2018 4:41 pm

Gamepimp wrote:My issue with the top of the image

Stop to post it here! It has no relation to scaler!

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Re: Scaler

Postby Grabulosaure » Tue Dec 11, 2018 8:45 pm

Here is an experiment.
I have posted scaler test versions of SNES and Genesis/Megadrive (on http://temlib.org/pub/mister/ascal/)
In the OSD menu, the first "Scaler:" entry allows to select different interpolers.

The questions are :
Which is better among the Polyphase interpolers ? Are there have visible defects ? No difference ? Which resolution are you using, which filter ?
Options are :
1) Poly
2) Poly Rounding
3) Poly Phase Acc
4) TEST (ignore the characters on top)
5) Original Altera VIP builds

Differences are very small.

Sub-question :
Which coefficients for default polyphase filter ?

[Note : I'm still optimising the scaler to achieve higher pixel rates, but these test versions, which implement additional hardware,
support lower freq. than final versions]

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Re: Scaler

Postby ghogan42 » Tue Dec 11, 2018 10:51 pm

Grabulosaure wrote:The questions are :
Which is better among the Polyphase interpolers ? Are there have visible defects ? No difference ? Which resolution are you using, which filter ?

[Note : I'm still optimising the scaler to achieve higher pixel rates, but these test versions, which implement additional hardware,
support lower freq. than final versions]


Just a note. Due to rounding errors (well the rounding is fine but row sums should be more important), a few of the coefficient sets in the filter repository that should have rows that sum to 128 actually have rows that sum to 127 or 129. The results is slight banding until I go back and fix them. That's not the fault of Grabulosaure's scaler. That's my fault in computing the coefficients and not checking for this carefully.

The ones that I have spotted so far include Gasussian_Sharp_01, Gaussian_Sharp_03, Bicubic.

These banding/line effects can change position based on the polyphase implementaion but aren't the scaler's fault.

Sorgelig
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Re: Scaler

Postby Sorgelig » Thu Dec 13, 2018 5:04 pm

Grabulosaure wrote:3) Poly Phase Acc

This one is the best polyphase version among others! When you will release it?
I test on LCD effect filter on white screen (240p suite). Other versions give stripes clearly visible. Phase Acc gives monotonic LCD effect (same as VIP).


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