OSSC (DIY video digitizer & scandoubler)

[Kez]

Is the (original) OSSC dead?
Last commit in github repo from 27/nov/2020, and lots of required and desirable features ignored.

Mike chi cleverly filling in the gaps.

Marqs has been working on the OSSC Pro for quite some time, so it makes sense that development has been quiet on the OSSC for a while. Worth bearing in mind it is an open source project, so there will always be potential for other people to do interesting things with the hardware.
I'm not sure what features you think have been ignored, but many of the things people ask about are simply not possible without a hardware revision.

[TrantaLocked_]

I think Kega was about one of the only emulators I've seen with a function of brighting an image with scanlines. For ossc it's like you need either pre-ADC gain to help with the offset, plus in combination with hybrid and either can lead to wash out effects if set too high. The better alternatives would be the RGB/YPbPr offset and gain levels, but you have to do them separate at each level and I'm sad that there's no one touch option to tick all three at once for doing this.

Yes the pre-ADC gain setting is too crude, at most you can do one step up from the default 8, anything more will crush everything. This setting is more useful when you need to go down a couple of steps.

I can never get the finer offset and gain level settings to look right after attempting to adjust them. If you or anyone else has a good combination of them to compensate for hybrid scanlines, please share. But I suspect that even an optimal adjustment of gain/offset is not as effective, and certainly not as convenient, as a gamma adjustment would be.

In my experience the fine Y gain works fine but the chroma gains scale the absolute value, meaning if you increase blue, anything below the chroma center point will become more yellow. That could help if there is something wrong with the signal itself which usually would be off in uniform, but if it's your monitor or you have a certain preference for visuals but then maybe not as helpful.

I see correct adjustment of gamma, offset and gain as all equally important but also not interchangeable as they all solve different problems. Currently the gamma problem cannot be solved on the OSSC.

[Elrinth]

Does anyone have good numbers/settings for:
PC-98
PC-88
FM Towns
X68000

For me, I need to play it upscaled else I , but then it cuts off alot of the vertical area.

[Sirotaca]

Does anyone have good numbers/settings for:
PC-98
PC-88
FM Towns
X68000

For me, I need to play it upscaled else I , but then it cuts off alot of the vertical area.

This page has settings for PC-98 and PC-88. I haven't tried the PC-88 settings, but I can confirm the PC-98 settings are correct for my Ap2 (aside from H. backporch which will vary a bit from one system to another).

[Elrinth]

thank you very much! <3

[bobrocks95]

The more I scrutinize the OSSC's output, the more disappointed I get lately. For Dreamcast I always figured I had flickering because of a bad VGA cable, but after swapping another in it's really the sampling phase- problem is, there's no perfect number for it, I just have to find a compromise between sharp pixels and horizontal flickering lines. Just in the 240p test suite alone, there's no setting that has 0 flickering between the checkerboard pattern and the gray background on the main menu. The sampling phase I found with the least flickering between the two screens, which is only noticeable if you're really looking for it, has some gray on the left edge of the white squares on the checkerboard pattern, so pixels aren't as sharp as they could be. It's just a compromise setting.

Then I tried the PC Engine in 256 optimized mode, and again, on a nice solidly colored screen at the start of Bonk, I either get a hair of ghosting on one color transition, or bump the sampling phase one notch and get a hair of ghosting on a different color transition.

So I'm back to using generic for everything for the sake of my sanity. Anybody else have as much trouble as I seem to dialing in sampling phase/optimal settings? The OSSC was of course a revelation for picture quality, and we're looking at dirty analog signals, but I'm really hoping the next generation of upscalers can make that last 15% quality uptick a lot simpler. The (consistent) ghosting on generic is always a bit of a buzzkill after messing with optimal settings for a bit.

[Thomago]

Have you tried toying around with the "Horizontal samplerate" setting additionally? I can't say anything about the Dreamcast, but my PSones won't produce a pixel perfect picture without dialing in a non-standard sampling rate.

[shroom2k]

It's more about H.samplerate, not about the phase. I find sometimes that when H.samplerate is absolutely correct, phase adjustment isn't even necessary.

That said, I couldn't for the life of me find the correct samplerate for some PS1 games on my PSPgo. And also for Sega 32x, the samplerate is different for 32x and for original Genesis games, even when both are technically 320x224.

Not sure if 'new generation' of scalers will be able to solve this issue - quite the opposite, if you can't find the optimal rate manually, it's likely that automatic settings will have even more problems.

[awe444]

He’s talking about Dreamcast though, which happens to output exactly the OSSC’s default horizontal sample rate (858 pixels). It could just be the allowed phase increments are too coarse? I’ve not experienced that myself but could be possible...

Going for precisely sampled, perfectly in phase settings for all consoles is fun, but there are examples where it’s just not practical (e.g. games that switch resolutions in game frequently), and sometimes it’s altogether impossible, like with the 32X, which has different phases for the Genesis rendered and 32X rendered components of the image. I’ve always wondered if someone could design a special kind of 32X patch cable (the one that connects the 32X to the Genesis) with some sort of inline dial that changes the video phase. Would be very niche but very cool.

[bobrocks95]

I mean yeah I'll give h samplerate a shot but I was checking the optimal timing wiki page and starting from FBX's profiles as a base- I was under the impression that there was a correct sample rate for each console/resolution, and only phase would change between units/setups? I messed with it a bit and things started looking really awful really quickly.

And yeah I'm not even on challenging content, I was just trying some basic fixed res stuff. I'm pretty sure if I could actually set the Dreamcast up perfectly it wouldn't ever need to be changed.

[TrendyNinja]

I hope somebody can help me with my query.

I have mainly PAL (50hz) 480i consoles and whenever I use passthrough on the OSSC for scanlines they look awful, thick and really noticeable. Yet if I go to line 2x (bob) they look brilliant and just how I want but unfortunately I don't like the bob effect. Is there no way I can get the scanlines to look the same in passthrough as they do in 2x (bob) for games running at 480i 50hz?

[Guspaz]

You shouldn't be using normal scanlines on 480i content at all. You can try setting the processing mode to line2x and then setting "Scanlines" to "auto", and the "Sl. alternating" setting to "on"which should enable alternating scanlines, which sort of tries to simulate a CRT.

If you want 480p-style scanlines on 480i content, you'll need a scaler with something like a motion adaptive deinterlacer that can also output 960p or 1080p. Something like the next-gen scalers (RT5X, OSSC Pro, PixelFX Morph).

[TrendyNinja]

Thank you Guspaz, that seems to have worked very well and helped reduce the noticeable bob significantly when using 2x.

[Sid]

Testing with both a PDP-LX509 and a KRP-500M with scanlines on, 2x mode has massively desaturated colour, and 3x mode has every second line with normal colour, and every other line desaturated.

I wuould guess that those displays use 4:2:0 color processing internally, which means that they average the color of two adjacent lines to recude the amount of data they need to process. With 100% strength scanlines, the TV sees a normal saturation on the non-blanked line and the pure black on the scanline evaluates to fully unsaturated, resulting in a large saturation drop after averaging.

It could be worse, I've seen some video capture devices that appear to just drop the color information from every second line, so turning on scanlines at maximum results in a black-and-white picture.

I bought an OSSC in the very early stages of its release and had issues as noted in the quotes above. I recently dug it out again, updated the firmware, experimented more extensively and am blown away with how good it looks. The "silver bullet" appears to be the "HDMI input" setting that I didn't realise was lurking in the menus of the Pioneers - it has "video" and "pc" as options. Switching to pc mode input (note - not the input labelled "pc" on the remote) was a complete revelation and now I have zero colour issues and have 5x working perfectly. In the meantime I'd added a 60 inch, last gen Pioneer to the collection - with hybrid and custom scanline options, and running on a phosphor-based display it feels really close to having a pro CRT at what works out to be around 50 inches of 4:3 screen.

I'm not sure how many old plasmas are compatible with 5x output (I had the impression that 3x was often the maximum) but I thought that this information could be useful for people looking at a cheap, high-quality option for a display to pair with the OSSC, or for those that hadn't managed to get the most out of a similar/same display. For what it's worth, I have an array of Sony and JVC pro CRTs to compare the image to. It's also a big deal to me that a game has to be moving very fast for the scanline effect to be smeared and made redundant (as it more readily would be with an LCD display).

Very happy customer here.

[ldeveraux]

I bought an OSSC in the very early stages of its release and had issues as noted in the quotes above. I recently dug it out again, updated the firmware, experimented more extensively and am blown away with how good it looks. The "silver bullet" appears to be the "HDMI input" setting that I didn't realise was lurking in the menus of the Pioneers - it has "video" and "pc" as options. Switching to pc mode input (note - not the input labelled "pc" on the remote) was a complete revelation and now I have zero colour issues and have 5x working perfectly. In the meantime I'd added a 60 inch, last gen Pioneer to the collection - with hybrid and custom scanline options, and running on a phosphor-based display it feels really close to having a pro CRT at what works out to be around 50 inches of 4:3 screen.

I'm not sure how many old plasmas are compatible with 5x output (I had the impression that 3x was often the maximum) but I thought that this information could be useful for people looking at a cheap, high-quality option for a display to pair with the OSSC, or for those that hadn't managed to get the most out of a similar/same display. For what it's worth, I have an array of Sony and JVC pro CRTs to compare the image to. It's also a big deal to me that a game has to be moving very fast for the scanline effect to be smeared and made redundant (as it more readily would be with an LCD display).

Very happy customer here.

I too have never realized 5x and have a Pioneer receiver. You're saying the only issue was changing the HDMI option to PC? COuld you point to where that option is so I could give it a whirl?

[Sid]

I too have never realized 5x and have a Pioneer receiver. You're saying the only issue was changing the HDMI option to PC? COuld you point to where that option is so I could give it a whirl?

Hmm..... "receiver"? I'm not sure if it'll help given that it's Pioneer tvs/monitors that I'm talking about, but I'll clarify regardless.

Go to Setup-->Options-->HDMI Input-->Signal Type-->Video/PC. Select PC and the message "The Signal operations mode has been changed" displays. I can't remember if a had to manually change the colour format to 4:4:4 but directly below the "HDMI Input" setting is "Video" which gives 4 different RGB colour format options. In video mode I would get an image at 5x but it was quite messed up and certainly nowhere near usable, PC mode works perfectly.

I hope that helps someone else out there even if it doesn't you.

[thchardcore]

You shouldn't be using normal scanlines on 480i content at all. You can try setting the processing mode to line2x and then setting "Scanlines" to "auto", and the "Sl. alternating" setting to "on"which should enable alternating scanlines, which sort of tries to simulate a CRT.

If you want 480p-style scanlines on 480i content, you'll need a scaler with something like a motion adaptive deinterlacer that can also output 960p or 1080p. Something like the next-gen scalers (RT5X, OSSC Pro, PixelFX Morph).

I think alternating scanlines on 480i looks perfect. It looks very odd without them.

[ldeveraux]

I too have never realized 5x and have a Pioneer receiver. You're saying the only issue was changing the HDMI option to PC? COuld you point to where that option is so I could give it a whirl?

Hmm..... "receiver"? I'm not sure if it'll help given that it's Pioneer tvs/monitors that I'm talking about, but I'll clarify regardless.

Go to Setup-->Options-->HDMI Input-->Signal Type-->Video/PC. Select PC and the message "The Signal operations mode has been changed" displays. I can't remember if a had to manually change the colour format to 4:4:4 but directly below the "HDMI Input" setting is "Video" which gives 4 different RGB colour format options. In video mode I would get an image at 5x but it was quite messed up and certainly nowhere near usable, PC mode works perfectly.

I hope that helps someone else out there even if it doesn't you.

Ah damn, I must have misread that. Thanks for the tutorial regardless!

[bobrocks95]

Gave sampling phase adjustments yet another try and got extremely frustrated again. This time for a triple bypass Genesis 2.

Literally impossible to set phase where both flicker is gone and pixel transitions don't have ringing. Every FBX video tutorial says to use the 240p test suite checkerboard pattern and adjust until it's sharp and there's no flickering. Cool, it looks good, until I back out and see what basically looks like a drop shadow to the right of everything. Adjust phase to get rid of that and the checkerboard is a flickering mess.

Tried every combination of Video LPF and Sync LPF, adjusting phase each time, and it's the same ringing to the right of pixels or flickery mess, pick your poison.

I'm extremely tempted to just splurge on a retrotink 5x pro and be done, but that's kind of wasteful since I know I'll be buying the Morph as soon as it's available for its HDMI input alone. The 5x also lacks aspect ratio control for Super Gameboy and possibly other OSSC features I use(no VGA input, no masking apparently?).

[fernan1234]

Why not just use generic 4:3 in the meantime? It will look very sharp as is with Genesis RGB, especially if you can afford to turn off the filtering.

[bobrocks95]

Why not just use generic 4:3 in the meantime? It will look very sharp as is with Genesis RGB, especially if you can afford to turn off the filtering.

Maybe I need to try with LPF off but it looked pretty awful in line x5 last I saw it. It also had ringing on top of being very soft, but I'll spend some time messing with it and see.

Any specific settings to tweak for generic? Figured it was set and forget.

[paulb_nl]

Tried every combination of Video LPF and Sync LPF, adjusting phase each time, and it's the same ringing to the right of pixels or flickery mess, pick your poison.

You have issues with various consoles? It really sounds like your OSSC is defective. Either that or you have something in between the consoles and OSSC that degrades the signal.

[bobrocks95]

Tried every combination of Video LPF and Sync LPF, adjusting phase each time, and it's the same ringing to the right of pixels or flickery mess, pick your poison.

You have issues with various consoles? It really sounds like your OSSC is defective. Either that or you have something in between the consoles and OSSC that degrades the signal.

Dreamcast is plugged straight into the OSSC VGA port and I was told that "it's really hard to dial in phase correctly on it" so apparently people just deal with it looking bad? Mine is very flickery on the checkerboard OR some solid colors.

GBI on the Gamecube and SNES 256 I believe I got dialed in perfectly. Saturn and Neo Geo look pretty good (I can't run 240p test suite on them). Genesis and PC Engine (and Dreamcast) I can't get perfect for the life of me.

EDIT: Genesis on generic x5 has light jailbars, still has the ringing, is of course softer, and the picture kinda wobbles left and right just a little. So definitely not going to use that.

320 Optimized ringing:
https://i.imgur.com/SkffzCn.jpg
https://i.imgur.com/GWtEjYe.jpg

Generic ringing:
https://i.imgur.com/He0uEkT.jpg

[paulb_nl]

GBI on the Gamecube and SNES 256 I believe I got dialed in perfectly. Saturn and Neo Geo look pretty good (I can't run 240p test suite on them). Genesis and PC Engine (and Dreamcast) I can't get perfect for the life of me.

Ok so you do have multiple consoles that look good.

I don't have a Dreamcast or Genesis but I would say it's bad cables. You said you swapped the VGA cable of the Dreamcast but did you swap it with a quality cable?

The ringing on the Generic image looks excessive. Do you see an improvement when you increase the LPF?

[headlesshobbs]

Ok no BS, no being a dick or an @$$hole... legit serious question.

How much memory does a blank scanline take up? No display information or anything, just a clear blank line with nothing on it to fill space with.

[bobrocks95]

GBI on the Gamecube and SNES 256 I believe I got dialed in perfectly. Saturn and Neo Geo look pretty good (I can't run 240p test suite on them). Genesis and PC Engine (and Dreamcast) I can't get perfect for the life of me.

Ok so you do have multiple consoles that look good.

I don't have a Dreamcast or Genesis but I would say it's bad cables. You said you swapped the VGA cable of the Dreamcast but did you swap it with a quality cable?

The ringing on the Generic image looks excessive. Do you see an improvement when you increase the LPF?

Genesis tried with 2 Retro-Access cables, one their older style and the new one with their Italian coax. Same results.
Dreamcast tried a generic VGA I had laying around and then a nice C2G 50212 6ft cord. Similar but different, could be my VGA box in theory (I believe it's a Retro-Bit). Apparently nobody makes VGA cables for a VGA console any more. Retro-Access doesn't even offer a Dreamcast connector in their custom cable builder.

LPF settings for sync or video just kinda shift the picture horizontally a bit. Video LPF off is maybe a touch sharper. Ringing looks identically awful at all settings.

Ok no BS, no being a dick or an @$$hole... legit serious question.

How much memory does a blank scanline take up? No display information or anything, just a clear blank line with nothing on it to fill space with.

Odd question. It'd either be 24 or 32 bits per pixel (4:4:4 RGB + A) * the horizontal resolution? Not sure what you're after though.

[headlesshobbs]

Odd question. It'd either be 24 or 32 bits per pixel (4:4:4 RGB + A) * the horizontal resolution? Not sure what you're after though.

Ok so awhile back I asked about the possibility of having games display in either 4x 224p/240p or 2x 480p in a 1080p frame so mostly all tv sets will show this at integer scaling for the games and having even scanlines, even if it meant having to window box the frame. Marqs told me that due to memory constraints this wouldn't be at all possible, but I see that we're doing 5x mode and I have to wonder what the 4x memory cost with blank lines vs 5x has to really come down to?

Even if it weren't possible, couldn't another method work of lying to the tv by telling it via flag it's receiving a 1080p signal, even though the ossc is still running video out at 960p? Much as everyone likes to place their bets on the pro board, I'd like to take an outside view of things and try to involve a little trickery to the process if there's any way to force integer to work.

[paulb_nl]

Genesis tried with 2 Retro-Access cables, one their older style and the new one with their Italian coax. Same results.
Dreamcast tried a generic VGA I had laying around and then a nice C2G 50212 6ft cord. Similar but different, could be my VGA box in theory (I believe it's a Retro-Bit). Apparently nobody makes VGA cables for a VGA console any more. Retro-Access doesn't even offer a Dreamcast connector in their custom cable builder.

LPF settings for sync or video just kinda shift the picture horizontally a bit. Video LPF off is maybe a touch sharper. Ringing looks identically awful at all settings.

The Retro-Access cables are reportedly of high quality so those shouldn't be the issue. So that only leaves your Genesis itself but I don't understand how the image can have so much ringing if a triple bypass has been installed. Unless it has been installed incorrectly.

Did you get your OSSC from VideoGamePerfection?

[Nrg]

Here's the "July 2021 update" question of what are the best OSSC compatible displays that are available to buy as new atm?
- Are VX3276-mhd or VX3276-mhd-2 still the "best" 32" displays?
- How about 27" displays?
- And 24" displays?

Must be compatible with all OSSC modes, including line5x mode, and support both PAL and NTSC machines. Good aspect ratio controls hopefully too

Thanks!

[bobrocks95]

Genesis tried with 2 Retro-Access cables, one their older style and the new one with their Italian coax. Same results.
Dreamcast tried a generic VGA I had laying around and then a nice C2G 50212 6ft cord. Similar but different, could be my VGA box in theory (I believe it's a Retro-Bit). Apparently nobody makes VGA cables for a VGA console any more. Retro-Access doesn't even offer a Dreamcast connector in their custom cable builder.

LPF settings for sync or video just kinda shift the picture horizontally a bit. Video LPF off is maybe a touch sharper. Ringing looks identically awful at all settings.

The Retro-Access cables are reportedly of high quality so those shouldn't be the issue. So that only leaves your Genesis itself but I don't understand how the image can have so much ringing if a triple bypass has been installed. Unless it has been installed incorrectly.

Did you get your OSSC from VideoGamePerfection?

Yeah it's from VGP. I figure I need to post pictures of other consoles in generic 4:3 when I get the chance. I get ringing on a SNES Jr. with a Voultar board installed as well. This is by all accounts just what I thought generic looked like.