OSSC (DIY video digitizer & scandoubler)

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Xer Xian
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Xer Xian »

Perhaps you're expecting too much from your sources. Whatever the sampling, and upscaling method, low-res 3D games can hardly look nice up close on a large screen (and no, integer scaling doesn't help at all).

Getting an OSSC for 480p (or 480i) pretty much only makes sense if your TV lacks analog inputs..
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Lawfer
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Lawfer »

Thomago wrote:I can't, as I don't know which resolutions your games run in by heart.
They pretty much all run at 720x480 480p 59.93Hz according to the OSSC.

Xer Xian wrote:Perhaps you're expecting too much from your sources. Whatever the sampling, and upscaling method, low-res 3D games can hardly look nice up close on a large screen (and no, integer scaling doesn't help at all).

Getting an OSSC for 480p (or 480i) pretty much only makes sense if your TV lacks analog inputs..
My TV has:

HDMI
Component YPbPr
SCART RGB
VGA
S-Video
Composite

Now I should mention this is not 480p feed in directly to the TV to way that hooking my PS2, Wii or GameCube would, it's 720x480p, Line2X to 1440x960p, so obviously the OSSC is more than a digitizer to change analog inputs into HDMI.
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Xer Xian
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Xer Xian »

Lawfer wrote:Now I should mention this is not 480p feed in directly to the TV to way that hooking my PS2, Wii or GameCube would, it's 720x480p, Line2X to 1440x960p, so obviously the OSSC is more than a digitizer to change analog inputs into HDMI.
Yes, and my point was that line doubling 480p content won't make low-res 3D graphics nice. It will look sharper than passthrough, but whether it's going to be an improvement over that is up for debate.
thebigcheese
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Re: OSSC (DIY video digitizer & scandoubler)

Post by thebigcheese »

The short version to your earlier question is that yes, it is normal. The OSSC is a linedoubler/tripler/quadrupler/quintupler, not a scaler, so all it can do is take the input signal and multiply it. That's how it achieves super low lag. This works great if you want super sharp pixels from 2D games, but it looks pretty bad with early 3D games because all the polygons have extra sharp edges. TVs use interpolated scaling, so they will take the input signal and instead of just doubling the existing pixels, they will make educated guesses (essentially) at what pixels should be used to fill in the remaining space. This tends to result in smoother results than the OSSC, which is great for 480p sources and for interlaced sources in particular. But the extra processing adds lag, so it's a trade-off. The allow upsample2x option is supposed to be a sort of middle ground, but I think the results really depend because I've noticed little to no difference with it on and off. Maybe I'm just doing something wrong there, I don't know.

In regards to the passthrough, yes, the OSSC is more than just a digitizer, but not when you select passthrough. Then it just digitizes the signal and sends it over HDMI to the TV.
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Thomago
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Thomago »

Lawfer wrote:They pretty much all run at 720x480 480p 59.93Hz according to the OSSC.
720 horizontal pixels - that's what the OSSC tries to sample. That isn't necessarily the games' horizontal resolution. Many games run in lower resolutions than that and if you try to sample 720 pixels, you are bound to get sampling artifacts.
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Lawfer
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Lawfer »

Thomago wrote:
Lawfer wrote:They pretty much all run at 720x480 480p 59.93Hz according to the OSSC.
720 horizontal pixels - that's what the OSSC tries to sample. That isn't necessarily the games' horizontal resolution. Many games run in lower resolutions than that and if you try to sample 720 pixels, you are bound to get sampling artifacts.
So how are you supposed to know what's a game real resolution?
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Thomago
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Thomago »

Emulation, analysis, trial and error... and as that's all laborious, enabling "Allow upsample2x" (which, if nothing else is changed, samples 1440 horizontal pixels in 480i/p Line2x mode, thereby circumventing obvious sampling artifacts) is the way to go.
Seriously, do it. This whole discussion is moot.
SavagePencil
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Re: OSSC (DIY video digitizer & scandoubler)

Post by SavagePencil »

Lawfer wrote: So how are you supposed to know what's a game real resolution?
Some systems are hardcoded, but you can usually tell pretty quickly if you have it tuned to the wrong setting. I'd suggest looking into FirebrandX's OSSC timings:

http://www.firebrandx.com/osscprofiles.html
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Lawfer
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Lawfer »

SavagePencil wrote:
Lawfer wrote: So how are you supposed to know what's a game real resolution?
Some systems are hardcoded, but you can usually tell pretty quickly if you have it tuned to the wrong setting. I'd suggest looking into FirebrandX's OSSC timings:

http://www.firebrandx.com/osscprofiles.html
Thank you but yeah I already know that website but it doesn't cover Wii, PS2, PSP, PS1, unfortuinaly, but I did use this guide to setup my GameCube for the Legend of Zelda Twilight Princess picture that I posted earlier.
nmalinoski
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Re: OSSC (DIY video digitizer & scandoubler)

Post by nmalinoski »

Xer Xian wrote:Getting an OSSC for 480p (or 480i) pretty much only makes sense if your TV lacks analog inputs..
And that's becoming more and more of a reality as newer TVs are released; the world is moving on.
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maxtherabbit
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Re: OSSC (DIY video digitizer & scandoubler)

Post by maxtherabbit »

nmalinoski wrote:
Xer Xian wrote:Getting an OSSC for 480p (or 480i) pretty much only makes sense if your TV lacks analog inputs..
And that's becoming more and more of a reality as newer TVs are released; the world is moving on.
the vast majority of new TVs being sold right now still have at least one component input
nmalinoski
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Re: OSSC (DIY video digitizer & scandoubler)

Post by nmalinoski »

maxtherabbit wrote:
nmalinoski wrote:
Xer Xian wrote:Getting an OSSC for 480p (or 480i) pretty much only makes sense if your TV lacks analog inputs..
And that's becoming more and more of a reality as newer TVs are released; the world is moving on.
the vast majority of new TVs being sold right now still have at least one component input
I thought that would have been one composite input.
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FBX
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Re: OSSC (DIY video digitizer & scandoubler)

Post by FBX »

Thomago wrote:
Lawfer wrote:They pretty much all run at 720x480 480p 59.93Hz according to the OSSC.
720 horizontal pixels - that's what the OSSC tries to sample. That isn't necessarily the games' horizontal resolution. Many games run in lower resolutions than that and if you try to sample 720 pixels, you are bound to get sampling artifacts.
In the case of the Gamecube, the signal is always set to 720 wide, and the game itself merely chooses how much of that to use. As such, you can make an optimally timed profile for 480p Gamecube that works for everything. In Windwaker, it uses 660 of the 720, but you still base the H. active on 720 as in my profile's note about this.
paulb_nl
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Re: OSSC (DIY video digitizer & scandoubler)

Post by paulb_nl »

Thomago wrote:Don't know if this was ever mentioned, but WHY is adjusting the sampling phase so very finicky? It's like the setting was randomly ignoring the set value every now and then. Taking away the signal (for example by resetting the console) helps getting the "correct" phase back again, but well... what's going on?
Tvp7002 digitizer clock doubler is used to reduce jitter but phase is unstable with it enabled. Set Allow H-PLL 2x to off. This is forced to off at optimized modes.
marqs wrote: I recently got a DE10-Nano development board and there's an add-on card I've made earlier consisting of a new video digitizer chip and a clock generator.
Which digitizer have you chosen?
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Thomago
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Thomago »

Thanks for the tip!
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maxtherabbit
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Re: OSSC (DIY video digitizer & scandoubler)

Post by maxtherabbit »

nmalinoski wrote:
maxtherabbit wrote:
nmalinoski wrote: And that's becoming more and more of a reality as newer TVs are released; the world is moving on.
the vast majority of new TVs being sold right now still have at least one component input
I thought that would have been one composite input.
a lot of brands just have one dual use analog input, where you can hook CVBS to the Y terminal if desired

I have seen some that omit composite entirely while retaining a component however
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Galdelico
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Galdelico »

FBX wrote:In the case of the Gamecube, the signal is always set to 720 wide, and the game itself merely chooses how much of that to use. As such, you can make an optimally timed profile for 480p Gamecube that works for everything. In Windwaker, it uses 660 of the 720, but you still base the H. active on 720 as in my profile's note about this.
As an aside, I tried your 480i profile and... It's most likely due to me using it on a PAL GameCube - and/or PAL60 behaving differently from native NTSC, maybe? - but it all looks noticeably too narrow (less in some games, like Mario Smash Football, way more with other ones, such as F-Zero GX and 1080°). While the combination of H.Samplerate 858 and H.Active 704 (for 4:3 aspect sampling) is expectedly a bit too wide, I found out 838/704 to be the most pleasing middle ground, for one single profile valid for all games.

Also - but it's all open to critiques and further tweaking from other users - the same settings seem to be good for PAL XBOX as well, both in PAL60 and PAL50 mode. As far as I can tell, with the XBOX there's nothing like the oddball multiple-resolutions thing going on with the GameCube, so all games - once again, both in PAL60 and 50 - appear to be scaled correctly, without ending up too narrow or too wide.
Last edited by Galdelico on Tue Sep 11, 2018 1:14 pm, edited 1 time in total.
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Fudoh
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Fudoh »

I found out 838/704 to be the most pleasing middle ground, for one single profile valid for all games.
but the sample right isn't exactly something that you can set to your liking in order to adjust the aspect ratio. If you don't get the sample rate right, fine details (like a checkerboard pattern) can't be fully resolved.
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Galdelico
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Galdelico »

Fudoh wrote:but the sample right isn't exactly something that you can set to your liking in order to adjust the aspect ratio. If you don't get the sample rate right, fine details (like a checkerboard pattern) can't be fully resolved.
Ah, I thought that one was the setting to tweak, instead of H.Active, in order to horizontally rescale the frame, and get it 'reasonably' proportioned, without it looking too thin or too wide.
I must say, I only do so with 480i sources, and I like to use Line2X and thicker scanlines with it anyway, so I don't really notice any quality loss on screen. Should I just leave it all set to exact 4:3 (877/720 or 858/704) and deal with slight stretching/squeezing?
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Fudoh
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Fudoh »

As FBX mentioned a little while ago, the OG XBox does use some kind of enforced internal recaling, so a sample rate mismatch won't be AS visible as with other systems.
Ah, I thought that one was the setting to tweak, instead of H.Active, in order to rescale the frame, and get it 'reasonably' proportioned, without it looking too thin or too wide.
the sample rate settings basically determines what happens FIRST on the OSSC and what the OSSC's multiplier engine gets handed to work with. So this should really be a match to your actual source signal.

By adjusting the h.active value (plus front/backporch settings) you can turn a 720x480p signal into a 704x480p one (also a valid DTV timing) or even a 640x480p VESA-like signal. This alters the aspect ratio in case your source uses horizontal underscan.
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Galdelico
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Galdelico »

Fudoh wrote:By adjusting the h.active value (plus front/backporch settings) you can turn a 720x480p signal into a 704x480p one (also a valid DTV timing) or even a 640x480p VESA-like signal. This alters the aspect ratio in case your source uses horizontal underscan.
Ha, ok. So - apologies if I'm still mistaken - H. Active works similarly to H-size controls on a CRT's service menu, and that's what you want to touch, when something on screen doesn't look 'correct' (once again, I don't go for pixel sampling with interlaced sources, and judge by eye).
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Harrumph
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Harrumph »

Galdelico wrote:
Fudoh wrote:By adjusting the h.active value (plus front/backporch settings) you can turn a 720x480p signal into a 704x480p one (also a valid DTV timing) or even a 640x480p VESA-like signal. This alters the aspect ratio in case your source uses horizontal underscan.
Ha, ok. So - apologies if I'm still mistaken - H. Active works similarly to H-size controls on a CRT's service menu, and that's what you want to touch, when something on screen doesn't look 'correct' (once again, I don't go for pixel sampling with interlaced sources, and judge by eye).
Right, and I went quite deep into this issue regarding the Gamecube together with Jademalo a couple of months ago in another thread: viewtopic.php?f=6&t=62790

I also felt aspect ratio did not look correct on my display, and my conclusion was h.active was best set to 704 for most games. But a few games behave more like Dreamcast and needs h.active 640. Then there seems to be two middle-ground settings as well, 683 (682.67) and 660, but those can be debated and partially up to taste.
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Galdelico
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Galdelico »

Harrumph wrote:Right, and I went quite deep into this issue regarding the Gamecube together with Jademalo a couple of months ago in another thread: viewtopic.php?f=6&t=62790

I also felt aspect ratio did not look correct on my display, and my conclusion was h.active was best set to 704 for most games. But a few games behave more like Dreamcast and needs h.active 640. Then there seems to be two middle-ground settings as well, 683 (682.67) and 660, but those can be debated and partially up to taste.
Oh, yeah, thanks! Jademalo has been super kind and gave me plenty of useful informations, during the past weeks.
Now, to your reply: are 683/660 alternative (to 704) H. Active values to try out with H.Samplerate 858, am I right?

Also, any chance you've got down anything similar for the PAL OG XBOX?
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Harrumph
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Harrumph »

Yes, samplerate should not be changed.

I don't have an Xbox, sorry.
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Galdelico
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Galdelico »

Harrumph wrote:Yes, samplerate should not be changed.

I don't have an Xbox, sorry.
No problem, and thanks! ^_-
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marqs
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Re: OSSC (DIY video digitizer & scandoubler)

Post by marqs »

marqs wrote:
Fudoh wrote:Well, I start with a 400 EUR offer for a replacement firmware that turns the OSSC into a scan converter to turn 480p and possibly 720p into 240p. I don't know if the OSSC has the hardware capacity (to my understanding one line needs to be buffered), but if it does, the offer stands. Certain quality requirements apply though, but I'm open for discussions.
While 480p->240p conversion should be technically possible with OSSC hw, the implementation would be hacky in one way or another. Either a very specific sampling rate would need to be used to enable valid clock ratio for Cyclone IV PLL (direct 262/525 not possible), or output timing would need to alternate between 262/263 lines (without interlace flag) which only CRTs have any chance of supporting.
Just in case someone is curious about the first method, a sampling rate of 2096 (8*262) with an output rate of 2100 (4*525) using 0.5x input pixel clock would be an example of a valid combination for turning 525-line signal into a 262-line signal. If nobody else is keen in trying his/her luck in a few months, I might as well look into that.
paulb_nl wrote:Which digitizer have you chosen?
ISL51002. Compared to TVP7002, it has a couple interesting features like automatic sampling phase adjustment and programmable fine-grained video LPF. Hopefully it'll be more robust with non-standard sync signals as well.
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Thomago
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Thomago »

Oh wow, that sounds neat.
rama
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Re: OSSC (DIY video digitizer & scandoubler)

Post by rama »

That's an impressive chip! I wish I had those features available in my project.. Everything is no compromise!
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maxtherabbit
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Re: OSSC (DIY video digitizer & scandoubler)

Post by maxtherabbit »

any chance of getting a limited range RGB output setting on a future software version using the new soft CPU?
NJRoadfan
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Re: OSSC (DIY video digitizer & scandoubler)

Post by NJRoadfan »

marqs wrote:ISL51002. Compared to TVP7002, it has a couple interesting features like automatic sampling phase adjustment and programmable fine-grained video LPF. Hopefully it'll be more robust with non-standard sync signals as well.
This is a newer 10-bit capable version of the chip that is on the DVI2PCIe card (most of the datasheet is cut and paste from the older chip). The older chip is pretty good, but Epiphan didn't bother to include any way to use the automatic sampling phase adjustment or a way to turn on the LPF..... which is really needed when capturing from sources like the SNES.
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