Integer scaling and interpolation

Discussion about displays and related hardware including MiSTer filters and video settings.
Kenzo
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Integer scaling and interpolation

Unread post by Kenzo »

Hi,

I am using a dell 4:3 1600x1200, with vscale=1 (x5 integer scale)

I understand that almost everything i play (neogeo/genesis/cps) is more often 224 horizontal than 240 and 256/512 instead of 320.

These aren't direct integers of 1600x1200 and so there is a border horizontally and also vertically.

The scaling options in the core (snes/neogeo) is set to "normal" and aspect ratio is set to "original"

My question is - How important is the "interpolation sharp" filter for my situation? I understand that interpolation isn't generally required for integer scales, however, this is when integer scaling is both horizontal and vertical.

I like the comp blend / scanlines filters and was wondering, should I really be using interpolation instead?
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aberu
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Re: Integer scaling and interpolation

Unread post by aberu »

It really depends on your display's capabilities. On my Samsung TV I need to use interpolation sharp turned on with integer scaling and with 5x mode to avoid some aesthetically displeasing issues with motion. But that's with vsync_mode=0 however. On my computer monitor I don't need to do this, so it's dependent upon the situation I guess.
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Kenzo
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Re: Integer scaling and interpolation

Unread post by Kenzo »

aberu wrote: Thu Jul 08, 2021 1:45 pm It really depends on your display's capabilities. On my Samsung TV I need to use interpolation sharp turned on with integer scaling and with 5x mode to avoid some aesthetically displeasing issues with motion. But that's with vsync_mode=0 however. On my computer monitor I don't need to do this, so it's dependent upon the situation I guess.
Ok, thanks.

Should I be using comp_H or HV filters?
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Re: Integer scaling and interpolation

Unread post by aberu »

Those are composite filters for different scaling methods in the video options of the OSD I believe, so if youw ant the blurry composite look you can use em. Just try em out and see how it looks. A lot of it is personal preference. For me, I have used this for SNES core before:

viewtopic.php?p=26547#p26547

Filter: COMP_SCAN_H_050 + Force 256 px mode: On + Vertical Crop 216p (5x)

This gives me a pretty aesthetically pleasing look:
oV6kswGX7V.png
oV6kswGX7V.png (1.74 MiB) Viewed 2966 times
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Re: Integer scaling and interpolation

Unread post by FoxbatStargazer »

If you like the comp scanlines there's no reason to switch, although it's also zero effort to just try the sharp interpolation shader too and switch back if its not to your liking.

If you use "normal" scale it will adjust the horizontal width to approximate 4:3, often times this is not a horizontal integer scaling. (Many cores now have HV integer scaling options if you really want horizontal integer scale.) However most/all? the scanline filters already include some horizontal interpolation/blur so this is usually not an issue. It's just important to use some kind of vertical integer scaling (what vscale_mode does) because otherwise your scanlines are likely to come out noticibly uneven.
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Re: Integer scaling and interpolation

Unread post by Kenzo »

FoxbatStargazer wrote: Fri Jul 09, 2021 12:43 am If you like the comp scanlines there's no reason to switch, although it's also zero effort to just try the sharp interpolation shader too and switch back if its not to your liking.

If you use "normal" scale it will adjust the horizontal width to approximate 4:3, often times this is not a horizontal integer scaling. (Many cores now have HV integer scaling options if you really want horizontal integer scale.) However most/all? the scanline filters already include some horizontal interpolation/blur so this is usually not an issue. It's just important to use some kind of vertical integer scaling (what vscale_mode does) because otherwise your scanlines are likely to come out noticibly uneven.
So technically, would it be better to use scaling option HV narrow/wide, rather than just leaving it "normal"? HV wide fills out the borders on the side, narrower seems to squish it

Ive tried sharp interpolation, i guess the image looks too..."digital"...the dithering effects are non-existent on a IPS...it looks too crisp. I wish i hadnt thrown out my crts over the years....i would have been able to tune my mister against a reference image
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Re: Integer scaling and interpolation

Unread post by FoxbatStargazer »

Kenzo wrote: Fri Jul 09, 2021 1:40 am
FoxbatStargazer wrote: Fri Jul 09, 2021 12:43 am If you like the comp scanlines there's no reason to switch, although it's also zero effort to just try the sharp interpolation shader too and switch back if its not to your liking.

If you use "normal" scale it will adjust the horizontal width to approximate 4:3, often times this is not a horizontal integer scaling. (Many cores now have HV integer scaling options if you really want horizontal integer scale.) However most/all? the scanline filters already include some horizontal interpolation/blur so this is usually not an issue. It's just important to use some kind of vertical integer scaling (what vscale_mode does) because otherwise your scanlines are likely to come out noticibly uneven.
So technically, would it be better to use scaling option HV narrow/wide, rather than just leaving it "normal"? HV wide fills out the borders on the side, narrower seems to squish it

Ive tried sharp interpolation, i guess the image looks too..."digital"...the dithering effects are non-existent on a IPS...it looks too crisp. I wish i hadnt thrown out my crts over the years....i would have been able to tune my mister against a reference image
I mean define "better"? You get things a bit sharper using narrow/wide but it's also not the original aspect ratio. Thanks to the blur in the scanlines filter you aren't likely to notice shimmering on scrolling or the like when using non-integer horizontal scale IMO, especially with the composite ones.

There can be a bit of a case for hv wide just to fill out a widescreen display a bit more. Another thing is for 320 wide cores like genesis, where it's only slightly wider than 4:3 and some games didn't always correct for the tall pixels on CRT (famous example: moon in Castlevania Bloodlines, or loops on Sonic games) But it's all preference at the end of the day.
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Re: Integer scaling and interpolation

Unread post by Kenzo »

FoxbatStargazer wrote: Fri Jul 09, 2021 2:17 am
Kenzo wrote: Fri Jul 09, 2021 1:40 am
FoxbatStargazer wrote: Fri Jul 09, 2021 12:43 am If you like the comp scanlines there's no reason to switch, although it's also zero effort to just try the sharp interpolation shader too and switch back if its not to your liking.

If you use "normal" scale it will adjust the horizontal width to approximate 4:3, often times this is not a horizontal integer scaling. (Many cores now have HV integer scaling options if you really want horizontal integer scale.) However most/all? the scanline filters already include some horizontal interpolation/blur so this is usually not an issue. It's just important to use some kind of vertical integer scaling (what vscale_mode does) because otherwise your scanlines are likely to come out noticibly uneven.
So technically, would it be better to use scaling option HV narrow/wide, rather than just leaving it "normal"? HV wide fills out the borders on the side, narrower seems to squish it

Ive tried sharp interpolation, i guess the image looks too..."digital"...the dithering effects are non-existent on a IPS...it looks too crisp. I wish i hadnt thrown out my crts over the years....i would have been able to tune my mister against a reference image
I mean define "better"? You get things a bit sharper using narrow/wide but it's also not the original aspect ratio. Thanks to the blur in the scanlines filter you aren't likely to notice shimmering on scrolling or the like when using non-integer horizontal scale IMO, especially with the composite ones.

There can be a bit of a case for hv wide just to fill out a widescreen display a bit more. Another thing is for 320 wide cores like genesis, where it's only slightly wider than 4:3 and some games didn't always correct for the tall pixels on CRT (famous example: moon in Castlevania Bloodlines, or loops on Sonic games) But it's all preference at the end of the day.

Is it better to let the .ini file handle scaling with vscale=1, or the cores OSD "Scale" option (v integer/narrower/wider) ?

Message #help
Also, If I were to switch "scale" to "v-integer" in the OSD and switch "320x224 aspect ratio" to "corrected" (fill out the screen horizontally),
would there be much difference compared to setting "wider HV integer" in the OSD (this also fills the screen out horizontally)
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Re: Integer scaling and interpolation

Unread post by FoxbatStargazer »

There's no effective difference between vscale=1 and v-integer, aside from you being able to switch it on and off on the fly in the core menu. However if you wanted half-integer settings like vscale 2 and 3, v-integer will not do that, it will only do whole integer steps and override the fraction-integer settings when in use.

I think hv-integer+ and 320x224 corrected yield the same results, however 320x224 corrected only applies to 320 wide resolutions. There are a few 256 wide genesis games for example which would be unaffected by the latter, and also quite a few Sega CD games using sub-320 resolutions for 3D or FMV.
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Re: Integer scaling and interpolation

Unread post by Kenzo »

FoxbatStargazer wrote: Fri Jul 09, 2021 3:24 pm There's no effective difference between vscale=1 and v-integer, aside from you being able to switch it on and off on the fly in the core menu. However if you wanted half-integer settings like vscale 2 and 3, v-integer will not do that, it will only do whole integer steps and override the fraction-integer settings when in use.

I think hv-integer+ and 320x224 corrected yield the same results, however 320x224 corrected only applies to 320 wide resolutions. There are a few 256 wide genesis games for example which would be unaffected by the latter, and also quite a few Sega CD games using sub-320 resolutions for 3D or FMV.
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