OSSC (DIY video digitizer & scandoubler)

The place for all discussion on gaming hardware
sofakng
Posts: 218
Joined: Fri Sep 02, 2016 1:30 am

Re: OSSC (DIY video digitizer & scandoubler)

Post by sofakng »

Thanks so much!

I'm still a bit confused by a few things.

1) GBA's native resolution is 240x160. Why is GBIHF outputting 480x360? I would have expected native resolution output (240x160) or exactly 2x (480x320).
2) What's the difference between resolution and line count? If the resolution is 480x360, where does the 375 come from?

I've been around for a bit (NESRGB installed, Hi-Def NES, etc) but I'm still confused but all this stuff!
User avatar
Fudoh
Posts: 13015
Joined: Mon Mar 06, 2006 3:29 am
Location: Germany
Contact:

Re: OSSC (DIY video digitizer & scandoubler)

Post by Fudoh »

The 360p setting is an output especially for the OSSC, which can turn it by further processing into a 720p-like signal.
If the resolution is 480x360, where does the 375 come from?
active vs. total line count (visible vs. front/back-porch/sync included).
User avatar
6t8k
Posts: 496
Joined: Wed Aug 14, 2019 2:44 pm

Re: OSSC (DIY video digitizer & scandoubler)

Post by 6t8k »

sofakng wrote:1) GBA's native resolution is 240x160. Why is GBIHF outputting 480x360? I would have expected native resolution output (240x160) or exactly 2x (480x320).
GBI-hf by default outputs a 240p (261p total) signal. With the GBA's 160 lines, this leaves 40 (black) lines at the top and bottom of the picture. If you choose the 'gbihf-ossc' preset included with GBI, your GameCube doubles the GBA's lines, so 160 x2 = 320, which gets embedded into a 360p active frame, leaving only 20 black lines at the top and bottom each.

There are no pixels in an analog signal: the 480x360 you're seeing is the video mode preset your OSSC's using (which by default is taking 480 samples per active line/600 per total line, the latter of which you can see by going to Sampling opt. -> Adv.timing (480x360) -> H.samplerate). Out of interest I was going to look up what resolution the GC's digital video port outputs in this case by taking a look at GCVideo-DVI's OSD, but the number is buried because the OSD gets garbled as shown here, and the resolution change info popup does not appear although I've enabled it in the settings.

360p is output by the 'gbihf-ossc' preset because, as Fudoh touched upon, that is suitable for further line-multiplication; 720 (2x) and 1080 (3x) are more compatible line counts as compared to 640 or 960 with a hypothetical 320-lines OSSC input. With 160 x3 you'd arrive at a low 480, which would be blurry on most digital displays.
headlesshobbs
Posts: 386
Joined: Sun Jul 04, 2010 11:14 pm

Re: OSSC (DIY video digitizer & scandoubler)

Post by headlesshobbs »

So whatever happened to progress with using the micro SD card for added memory?

Allowing system profiles per input would have made a number of configurations a whole lot easier.
"Don't HD my SD!!"
nmalinoski
Posts: 1974
Joined: Wed Jul 19, 2017 1:52 pm

Re: OSSC (DIY video digitizer & scandoubler)

Post by nmalinoski »

headlesshobbs wrote:So whatever happened to progress with using the micro SD card for added memory?
Closest thing I can think of is profile import, which has been available for a while now. I think there's still too few resources available to do anything significant with the SD card.
whatamansion
Posts: 24
Joined: Thu May 07, 2020 6:33 am

Re: OSSC (DIY video digitizer & scandoubler)

Post by whatamansion »

Is something wrong with my SNESRGB or is all this normal to have the halo effect on the 4:3 Generic setting of the OSSC? I'm using Voultar's board (he didn't install it tho) and running in 5x mode. All modes display it. The left side of the the screen has a black looking line running down and the white halo next to it. Here's some pics (sorry my cam isn't the greatest):

Pic 1 (left side of screen): https://i.imgur.com/wHrpION.jpg
Pic 2: https://i.imgur.com/00AX85s.jpg
Pic 3: https://i.imgur.com/iErRroe.jpg

I can't seem to make it disappear in 4:3 Generic using the sampling phase option. It shows up on both Scart and HD Retrovision cable. The only way to make it mostly go away is set it to 256x240 optimal. Even then, I can't get sampling phase perfect (is it possible to?) as there's still some very, very, very faint darker haloing I can see in certain colors. But you have to get up to the screen to really see it.

I've also noticed the refresh changing. I can turn it on one time and it's 60.08hz and the other time 60.19hz, etc. It seems to be running fine though. I've not had any issues. I just notice it changing.
User avatar
6t8k
Posts: 496
Joined: Wed Aug 14, 2019 2:44 pm

Re: OSSC (DIY video digitizer & scandoubler)

Post by 6t8k »

whatamansion: did you try increasing Post-proc. -> Reverse LPF?
whatamansion wrote:I've also noticed the refresh changing. I can turn it on one time and it's 60.08hz and the other time 60.19hz, etc. It seems to be running fine though. I've not had any issues. I just notice it changing.
Yeah, the OSSC is not always accurate about that. It's not like the vertical refresh rate your SNES itself outputs is changing.
whatamansion
Posts: 24
Joined: Thu May 07, 2020 6:33 am

Re: OSSC (DIY video digitizer & scandoubler)

Post by whatamansion »

6t8k wrote:whatamansion: did you try increasing Post-proc. -> Reverse LPF?
whatamansion wrote:I've also noticed the refresh changing. I can turn it on one time and it's 60.08hz and the other time 60.19hz, etc. It seems to be running fine though. I've not had any issues. I just notice it changing.
Yeah, the OSSC is not always accurate about that. It's not like the vertical refresh rate your SNES itself outputs is changing.
I just tried it. It amplifies the haloing even more. Here's 256x240 optimized with the reverse LPF set to 3 vs. reverse LPF set to off. It amplifies the slight darker haloing I can see in this mode.

with reverse LPF: https://i.imgur.com/cT6jQes.jpg

without reverse LPF: https://i.imgur.com/3mCMxal.jpg

See, it's hard to notice in 256x240 optimized in the second pic. You can't even see it in the pic, but in person it's very slightly apparent when you get close to the screen and on certain colors. I'm just wondering if it's even possible to get sampling completely perfect.
User avatar
6t8k
Posts: 496
Joined: Wed Aug 14, 2019 2:44 pm

Re: OSSC (DIY video digitizer & scandoubler)

Post by 6t8k »

If adjusting sampling phase alone doesn't cut it, you could try slightly adjusting H.samplerate/H.s.rate adj, which can yield better results in some cases. Re-align sampling phase after that.

You could also give FBX's optimized profiles a try, or follow his SNES OSSC optimal timing tutorial and see if you can get better results with that. I'm not familiar with the hardware mod you mentioned, but I could imagine its presence having an influence on the observed artifacts. Otherwise I'm out of ideas currently (outside of hardware mods / trying a different console).

---
Edit, referring to your photos of 256x240 optimized mode: if the next sample is supposed to be darker, it becomes too dark at first, the sample after that has the correct shade. And vice versa: if the next sample is supposed to be brighter, it becomes too bright at first, the sample after that has the correct shade. That matches the characteristics of overshoot/ringing, which would also explain why it was accentuated by the RLPF. If it's not some other artifact introduced by your monitor or camera, then I can even see the ringing gradient in your photos from generic mode. In this case, it could be worthwhile to try a different value for Video in proc -> Video LPF. Avoid running the signal through multiple LPFs: assuming this is the hardware mod you have, you could also try shorting the LPF jumper (you could try to carefully touch both contacts with a short wire to see if it would change things for the better). It would be hard, if not impossible to work around that issue by changing the OSSC's sampling. It wouldn't tackle the root cause.

If it's not cascaded LPFs, if you have an RGB-capable CRT or an oscilloscope, you could also feed your SNES's signal into it and see if you can spot any trace of that effect. This would help isolating the cause (your console or your OSSC).
lechu
Posts: 107
Joined: Sat Aug 15, 2015 12:52 am

Re: OSSC (DIY video digitizer & scandoubler)

Post by lechu »

Quick question.

I love my OSSC, but it seems like the colours aren't amazingly vibrant when compared to my PVM. I've calibrated my TV, so I think it's an OSSC setting.

I've turned up the pre-ADC gain a bit from 8, and it looks closer to my PVM. But I'm not sure what the pre-ADC gain is actually doing. I just want to make sure I'm not messing with something I shouldn't be messing with. Is that the right way about adjusting my OSSC to get a closer match to my PVM?
User avatar
Konsolkongen
Posts: 2309
Joined: Fri May 16, 2008 8:28 pm
Location: Denmark

Re: OSSC (DIY video digitizer & scandoubler)

Post by Konsolkongen »

What kind of TV are you using the OSSC on?
lechu
Posts: 107
Joined: Sat Aug 15, 2015 12:52 am

Re: OSSC (DIY video digitizer & scandoubler)

Post by lechu »

It's a TCL 43S405 4K TV. I've noticed this issue on my prior TV as well. The PVM is an Ikegami TM14-17R.
User avatar
maxtherabbit
Posts: 1763
Joined: Mon Mar 05, 2018 4:03 pm

Re: OSSC (DIY video digitizer & scandoubler)

Post by maxtherabbit »

marqs wrote:
maxtherabbit wrote:Seems like the mode detect logic needs a rework please marqs, since these PC (and GBI) modes are clearly distinguishable from their DTV counterparts by line count, it seems like there is no need to tie the logic to physical input anymore.
Certain mode presets are enabled only for certain physical inputs - the original idea was to prevent collisions with modes which have very similar line counts but are typically used with specific sources (e.g. PC via VGA input). For example, both 576p and 800x600_56 standards use 625 lines so there's no way to select the correct preset based on that information only. Nowadays the fw also considers refresh rate in these kind of cases when making the selection so the filtering based on physical inputs could be loosened or maybe even dropped altogether.
for those situations where mode cannot be determined from total lines + refresh rate, would a remote button to toggle between the "X in sampler" modes for the current detected line count be feasible? like 720x480 vs 640x480 and 720x400 vs 640x400? Optionally the same toggle could also cycle through the various 240p optimized modes when a 240p source is present
User avatar
marqs
Posts: 1034
Joined: Sat Dec 15, 2012 12:11 pm
Location: Finland

Re: OSSC (DIY video digitizer & scandoubler)

Post by marqs »

maxtherabbit wrote:
marqs wrote:
maxtherabbit wrote:Seems like the mode detect logic needs a rework please marqs, since these PC (and GBI) modes are clearly distinguishable from their DTV counterparts by line count, it seems like there is no need to tie the logic to physical input anymore.
Certain mode presets are enabled only for certain physical inputs - the original idea was to prevent collisions with modes which have very similar line counts but are typically used with specific sources (e.g. PC via VGA input). For example, both 576p and 800x600_56 standards use 625 lines so there's no way to select the correct preset based on that information only. Nowadays the fw also considers refresh rate in these kind of cases when making the selection so the filtering based on physical inputs could be loosened or maybe even dropped altogether.
for those situations where mode cannot be determined from total lines + refresh rate, would a remote button to toggle between the "X in sampler" modes for the current detected line count be feasible? like 720x480 vs 640x480 and 720x400 vs 640x400? Optionally the same toggle could also cycle through the various 240p optimized modes when a 240p source is present
I've updated the mode detection to be independent of physical input except for HDTV modes where it assumes trilevel sync is used with non-TTL sync sources. 480p sampler in auto mode subsequently uses hsync length to select between 720x480 and 640x480 presets. For 720x400 vs 640x400 I don't think such reliable difference exists so the selection would still need to be done manually. I'll consider the proposed hotkey idea.
User avatar
maxtherabbit
Posts: 1763
Joined: Mon Mar 05, 2018 4:03 pm

Re: OSSC (DIY video digitizer & scandoubler)

Post by maxtherabbit »

marqs wrote:I've updated the mode detection to be independent of physical input except for HDTV modes where it assumes trilevel sync is used with non-TTL sync sources. 480p sampler in auto mode subsequently uses hsync length to select between 720x480 and 640x480 presets. For 720x400 vs 640x400 I don't think such reliable difference exists so the selection would still need to be done manually. I'll consider the proposed hotkey idea.
excellent!
User avatar
Konsolkongen
Posts: 2309
Joined: Fri May 16, 2008 8:28 pm
Location: Denmark

Re: OSSC (DIY video digitizer & scandoubler)

Post by Konsolkongen »

The up/down keys (out of menus) would be great for quickly switching between these profiles.
User avatar
maxtherabbit
Posts: 1763
Joined: Mon Mar 05, 2018 4:03 pm

Re: OSSC (DIY video digitizer & scandoubler)

Post by maxtherabbit »

marqs, you are a fucking champion man

you've implemented or corrected literally everything I've asked for over the years, thank you!
fandangos
Posts: 144
Joined: Tue Sep 18, 2012 3:48 am

Re: OSSC (DIY video digitizer & scandoubler)

Post by fandangos »

Hi all,

I own the OSSC and use it with my PS1.
I'm debating if I should buy the PS1Digital kit and install it on my PS1.

I know digital all the way is the best image possible but I'm wondering if someone have some screen caps comparing other HDMI solutions for old consoles and the ossc with right settings.

The two I would like to find a good comparison is the DCDigital and the UltraHDMI for the N64 compared to RGB using the OSSC.
Does any one have any screen capture or can give some opinion on this?

Is the difference really noticeable?
Plumbern
Posts: 1
Joined: Wed Jan 18, 2017 8:09 am

Re: OSSC (DIY video digitizer & scandoubler)

Post by Plumbern »

Hi. Can you recommend any good monitors with low/lowest input lag that's works with the ossc?
headlesshobbs
Posts: 386
Joined: Sun Jul 04, 2010 11:14 pm

Re: OSSC (DIY video digitizer & scandoubler)

Post by headlesshobbs »

Dumb question to ask, but do any of the same methods for running upsample x2 apply to 240p sources?

Especially when you get them displaying beyond 720p resolutions. Panel tech tends to make the pixels too artificial regardless and I'd like to see if de-sharpening them is at all possible without having to mess with a tv remote.
"Don't HD my SD!!"
User avatar
Fudoh
Posts: 13015
Joined: Mon Mar 06, 2006 3:29 am
Location: Germany
Contact:

Re: OSSC (DIY video digitizer & scandoubler)

Post by Fudoh »

Dumb question to ask, but do any of the same methods for running upsample x2 apply to 240p sources?
That's basically the same what generic vs. optimized sampling does for 240p sources.
headlesshobbs
Posts: 386
Joined: Sun Jul 04, 2010 11:14 pm

Re: OSSC (DIY video digitizer & scandoubler)

Post by headlesshobbs »

That's what I thought it was.

I just wish I knew of some way to increase the filtering at 5x.
"Don't HD my SD!!"
User avatar
Fudoh
Posts: 13015
Joined: Mon Mar 06, 2006 3:29 am
Location: Germany
Contact:

Re: OSSC (DIY video digitizer & scandoubler)

Post by Fudoh »

I just wish I knew of some way to increase the filtering at 5x.
you want a softer picture at 5x ? Why then use 5x in the first place. If you run to your display in 3x instead and the let the display add another scaling step, it might give you what you're looking for.

That's basically the reason why I find 4x and 5x completely useless for scanlines (unless you use a shader). The whole reason for 4x and 5x is to push the sharpness to its max.
User avatar
Konsolkongen
Posts: 2309
Joined: Fri May 16, 2008 8:28 pm
Location: Denmark

Re: OSSC (DIY video digitizer & scandoubler)

Post by Konsolkongen »

Weird, I find 5x is the best possible one for scanlines use, as you can position them more in between the pixels using custom scanlines rather than the default where they are placed at the top or the bottom.
User avatar
Fudoh
Posts: 13015
Joined: Mon Mar 06, 2006 3:29 am
Location: Germany
Contact:

Re: OSSC (DIY video digitizer & scandoubler)

Post by Fudoh »

Certainly when it comes to positioning and control, but the sharpness of a 5x output is simply too high. There's zero resemblence to anything CRT-like, especially on large screens.
User avatar
BuckoA51
Posts: 3358
Joined: Sat Oct 02, 2010 10:08 am
Location: Ireland
Contact:

Re: OSSC (DIY video digitizer & scandoubler)

Post by BuckoA51 »

Certainly when it comes to positioning and control, but the sharpness of a 5x output is simply too high. There's zero resemblence to anything CRT-like, especially on large screens.
I'm in this camp too, especially after actually getting/seeing some CRTs since I've lived in Ireland, my memory wasn't faulty :)

Each to their own though.
OSSC Forums - http://www.videogameperfection.com/forums
Please check the Wiki before posting about Morph, OSSC, XRGB Mini or XRGB3 - http://junkerhq.net/xrgb/index.php/Main_Page
User avatar
Konsolkongen
Posts: 2309
Joined: Fri May 16, 2008 8:28 pm
Location: Denmark

Re: OSSC (DIY video digitizer & scandoubler)

Post by Konsolkongen »

Fudoh wrote:Certainly when it comes to positioning and control, but the sharpness of a 5x output is simply too high. There's zero resemblence to anything CRT-like, especially on large screens.
I’m weird that way. On one hand there is a lot I don’t like about CRTs like uniformity being all over the place and overscan causing you to loose the corners on most sets. But then I still really like the scanlines on 240p games :D

What are you using? 720p generic?
User avatar
Fudoh
Posts: 13015
Joined: Mon Mar 06, 2006 3:29 am
Location: Germany
Contact:

Re: OSSC (DIY video digitizer & scandoubler)

Post by Fudoh »

What are you using? 720p generic?
when I can't use a shader I usually use 720p, either generic or optimized with medium horizontal and light vertical scanlines and run that through a geometry processor that gives me a very slight curvature effect.
User avatar
orange808
Posts: 3196
Joined: Sat Aug 20, 2016 5:43 am

Re: OSSC (DIY video digitizer & scandoubler)

Post by orange808 »

Fudoh wrote:
What are you using? 720p generic?
when I can't use a shader I usually use 720p, either generic or optimized with medium horizontal and light vertical scanlines and run that through a geometry processor that gives me a very slight curvature effect.
+1 on the geometry processing. The effect can be very nice.

I hope the OSSC Pro eventually gets some warping features and replaces most of my gear. Although, I bet geometry is going to be a low priority feature. :(

Which machine did you prefer right now?
We apologise for the inconvenience
headlesshobbs
Posts: 386
Joined: Sun Jul 04, 2010 11:14 pm

Re: OSSC (DIY video digitizer & scandoubler)

Post by headlesshobbs »

5x gives you the highest line count and puts it closer to the pvm range.
"Don't HD my SD!!"
Post Reply