OSSC (DIY video digitizer & scandoubler)

[Harrumph]

trying a different camera this time.

Samsung LN40+OSSC line 3x (TV can't accept line 4x or 5x without an additional processor) scanlines: 100%)

That looks nice and even! Curiously, it looks like lx3 is scaled into 5 lines (with two blacked out), ie effectively lx5, but that would imply the image gets vertically cropped...?

[AetherSmyth]

Hi,
Is it possible to use a 75ohm CSYNC signal on the AV3 input? I was hoping to connect a gscartsw Lite with "Sync Regeneration" enabled.

If you don't mind me asking, why not just use AV1? If it's coming from a gscartsw_lite, you'd already have to be converting from SCART to HD15 to get it into AV3.

How realistic would it be to make a post process filter for something like after effects that takes an x2/x3/x4 captured video with hard edged pixels and outputs a 4k video with simulated sub-pixel structure?
And on a step up from that, how realistic would it be to make a very simple HDMI to HDMI box that takes an x2/x3/x4 input and spits out the simulated sub-pixel 4k thing in real time?

I feel like the best way to do something like this would be to have it as a post processor device and keep it entirely digital, rather than making it an ADC+scaler as well. Adding this functionality into a scaler would take a ton of resources and jack up the price, and on the opposite side adding scaler functionality into something like this would do the same.
Would it be better to feed it an x4 scaled image, then have it generate a 256x240 signal to work from, or would it be better to feed it essentially raw 240p passthrough and then have it do all the scaling?

I'd totally buy a device dedicated to taking x2/x3/x4 scaled digital signals and pumping out a 4k simulated CRT.

I actually toyed around with trying to figure out something along those lines around New Year's...

Unfortunately, there don't seem to be many cost-effective solutions for HDMI input that are accessible to consumers and hobbyists. I'm mainly a programming guy without much expertise in hardware design, so for the most part I tried to see if any hacker-board existed that might work. I found a handful with HDMI input and output capabilities, but all except one were limited to 1080p output (which is a little iffy as to whether it could simulate small enough sub-pixels). The one I went with, the Firefly RK3288 Reload, was an ARM board advertised for all sorts of video processing and machine vision tasks, but when I actually tried it out I found that the HDMI input added a bunch of fine noise. Not even sure how that happened, given that it should have been an all-digital path, but it was no good for anything to do with HD video and their support was worse than useless.

I did also look into sourcing an HDMI deserializer IC, but they don't seem to be available through consumer channels, and the manufacturers won't even respond if you're just a hobbyist.

Maybe someone else will have better luck?

[Jademalo]

Ah man, that's a shame

[Monogamous]

Hi,
Is it possible to use a 75ohm CSYNC signal on the AV3 input? I was hoping to connect a gscartsw Lite with "Sync Regeneration" enabled.

If you don't mind me asking, why not just use AV1? If it's coming from a gscartsw_lite, you'd already have to be converting from SCART to HD15 to get it into AV3.

I'm having Blue Jeans Cable make me a custom output cable for the switch that breaks off the audio to XLR plugs, due to the lack of a proper minijack audio output on the Lite revision. So it doesn't really matter what kind of plug is on the other end.

The reason I want to do this is for the sake of having a (relatively) easy means of hooking up the PS2. The model I have is an SCPH-90001, which cannot be modified for proper VGA output, at least as far as I know. Horizontal and vertical sync are available, but there will be noise issues when outputting 480p due to the SoG pulses.

I'm hesitant to a get a different PS2 model, as the 90001 seems to have a particular proficiency with PS1 games, which generally seem to run better than they do on the earlier consoles. It also has a couple other advantages, such as a better/more reliable disc reader and a more advanced video encoder IC that has a built-in DAC. I also bought it new and know its history.

So that leaves the standard SoG connection as the best option for 480p games. Using a typical sync-on-luma SCART cable seems to be the best option, as I can just use the standard Multi Out port that's already on the system. Additonally, using a seperate input allows me to use the required settings for pixel-perfect digitization of PS1 games (a sampling phase of 429) without having to switch profiles.

My thinking is that the AV1 input would be more ideal for the PS2, due to the integrated sync seperator and more advanced low-pass filtering, and that the AV3 input would be more ideal for the gscartsw as it already outputs a clean CSYNC signal. Not that any of this is a particularly huge deal, but if it would work, I don't see any reason to purposefully implement a more complicated/inconvenient connection scheme.
--
One quick side-note. This isn't directed at anyone in particular, but I've been a bit curious for a while as to why there hasn't been a proper FPGA HDMI implementation for PS2. I came across a thread where that same question had been asked, and one of the replies noted that it was "easy" to get optimal image quality from the PS2. Another mentioned that backwards-compatible PS3s were available, but the quality of the emulation on those is pretty abysmal, particularly when it comes to audio.

The PS2 has a number of system-specific quirks, including:
- a mediocre YPbPr output
- a 480p sync type that's inconvenient for pretty much everyone
- the lack of a proper TTL CSYNC output
- frequent resolution changes
- a non-standard sampling phase requirement for PS1 games
that would seem to make it a prime candidate for a proper digital solution.

[Fudoh]

with a standard scart cable (no matter which sync configuration) you won't get 480p from a PS2 through the GScartSw Lite, since it won't detect the input as active, once the PS2 switches to SoG and disable the composite video/sync/luma outputs.

If you can get TTL Sync levels from a standard sync output by adding an Extron RGB/sync interface.

I've been a bit curious for a while as to why there hasn't been a proper FPGA HDMI implementation for PS2.

because the majority of the titles on the PS2 are 480i and for that you want proper motion adaptive deinterlacing, which an affordable FPGA implementation can't deliver yet.

- a mediocre YPbPr output

you make it sound worse than it is. It's just a little noisy, which is nothing a proper LPF can't fix.

[bobrocks95]

because the majority of the titles on the PS2 are 480i and for that you want proper motion adaptive deinterlacing, which an affordable FPGA implementation can't deliver yet.

Just curious Fudoh, do you know if high-end FPGA-based solutions for deinterlacing are out there? As in, is it easy enough to do, we just need costs to go down?

[Monogamous]

with a standard scart cable (no matter which sync configuration) you won't get 480p from a PS2 through the GScartSw Lite, since it won't detect the input as active, once the PS2 switches to SoG and disable the composite video/sync/luma outputs. If you can get TTL Sync levels from a standard sync output by adding an Extron RGB/sync interface.

What I'm hoping to do is hook up the PS2 to AV1, and the Lite to AV3. I'd rather tap the native sync signals from the console than add a "sync processor" to my setup if it comes to that, or just swap the SCART cables on the back of the OSSC. To my knowledge, the analog sync outputs from the encoder aren't turned off when it switches to SoG mode.

Regarding deinterlacing, I'm not sure why this would have to be done on the FPGA. Most mid to high-end TVs should have competent scaling chips, so the only thing you'd really need it for is implementing a fix for resolution changes on PS1 games.

One idea I had for that was programming in something that would monitor the clock speed of the IO chip, which would change the "deinterlacing" mode when the chip was downclocked. I'm not too familiar with this kind of thing, though, so I don't know how feasible it would be.

you make it sound worse than it is. It's just a little noisy, which is nothing a proper LPF can't fix.

I guess. My point is less that all these problems are crippling, and more that there are a lot of minor annoyances with the console that could be fixed with a convenient, one-cable solution.

[bobrocks95]

I don't know how common it is at all, but some displays don't accept 480i over HDMI. The TV I would use it on doesn't.

And I'd assume TVs use a deinterlacing method best suited for video rather than games, whereas an FPGA could be specialized.

[Monogamous]

I'd think that a good deinterlacer would be just as good for one as the other, as the goal in both cases is to simply make the image look like a native 480p signal.

[Guspaz]

There are many types of deinterlacing, though, with very different visual impacts and latencies. The OSSC bob deinterlacing is very fast, but is decently flickery.

superg (developer of the gscartsw-lite) is working on a PS2 sync adapter. It will basically automatically switch sync sources such that it always outputs RGBS regardless of if you're doing 480i or 480p RGB. This can simply be fed into a gscartsw-lite like all other consoles.

The custom cables you describe are not required, as the OSSC routes the audio pins from the SCART connector to its 3.5mm jack. This is a passive electrical connection and doesn't require the OSSC to be powered. A simple scart-to-scart cable can be used to connect the gscartsw-lite to the OSSC with the audio output on the OSSC used from there. Basically, there is no reason you can't simply connect everything to the gscartsw and then connect that to AV1.

[Monogamous]

Low-latency "bob" deinterlacing can already be inexpensively implemented on FPGA hardware, but as Fudoh correctly pointed out, it's not really an adequate solution for a console that primarily outputs interlaced video. I don't think that's what he was referring to by a deinterlacing solution that's optimized for gaming.

By the way, is there any particular reason why I should have to use AV1? I'm aware of the alternatives you're describing--I'm just trying to find out what's possible.

[Unseen]

I did also look into sourcing an HDMI deserializer IC, but they don't seem to be available through consumer channels, and the manufacturers won't even respond if you're just a hobbyist.

Bunnies NeTV fed the signal directly into a Spartan 6 FPGA and implemented everything in there, but it's limited to 1080i due to speed limitations of the chip. The code for it is available somewhere on Github, I've used a hacked version of it to debug the output of GCVideo-DVI.

One quick side-note. This isn't directed at anyone in particular, but I've been a bit curious for a while as to why there hasn't been a proper FPGA HDMI implementation for PS2.

I looked at it and shelved it again because I'm currently too lazy to solder 24+ video data wires to either the DAC or graphics chip. Same for PS1.

[Guspaz]

Low-latency "bob" deinterlacing can already be inexpensively implemented on FPGA hardware, but as Fudoh correctly pointed out, it's not really an adequate solution for a console that primarily outputs interlaced video. I don't think that's what he was referring to by a deinterlacing solution that's optimized for gaming.

By the way, is there any particular reason why I should have to use AV1? I'm aware of the alternatives you're describing--I'm just trying to find out what's possible.

AV3 has several issues:

1) It has very limited video LPF support, and thus is only suitable for either 1080p input (the or very clean video signals. In other words, it's not suitable for handling any random console out there.
2) It does not support 75ohm sync, which is what you should be getting from most consoles by the end of their SCART cable and what you'll get from the gscartsw-lite
3) It does not properly support 480i resolution when using separate H/V sync, currently a partial workaround is in place
4) I have a vague recollection of AV3 having less ESD protection, but I could be misremembering

Since you're starting with SCART output, the simplest solution is to just use a SCART-to-SCART cable, instead of trying to convert from SCART to VGA, which with the OSSC will require a sync level conversion as well as have the other limitations.

[Harrumph]

*AV3

Gscartsw lite has its own LPF circuit, but I think he'll run into sync issues for sure.

[Guspaz]

gscartsw-lite does not have an LPF at all. You're thinking of gscartsw, which had an LPF that could not be disabled without soldering.

[Harrumph]

Ah right, my mistake. Then he really should connect his switch to AV1, imo.

[Blair]

That looks nice and even! Curiously, it looks like lx3 is scaled into 5 lines (with two blacked out), ie effectively lx5, but that would imply the image gets vertically cropped...?

thanks!, its scaling the 720p line 3x into a 1080p image as it's a 1080p native display line 5x looks a bit different to me then 3x on this tv (see below)

How realistic would it be to make a post process filter for something like after effects that takes an x2/x3/x4 captured video with hard edged pixels and outputs a 4k video with simulated sub-pixel structure?
And on a step up from that, how realistic would it be to make a very simple HDMI to HDMI box that takes an x2/x3/x4 input and spits out the simulated sub-pixel 4k thing in real time?

theorectly something like that is possible now with an HDMI input card and a realtime shader engine, somthing like reto arche's video input shader could work but the latency/input lag might be high without optimizing the chan somehow. such an idea was discussed a few times in the past but not much in the way of development as far as I know. you can see some of my CRT shader experiments in the this thread. (http://shmups.system11.org/viewtopic.ph ... r#p1198588)

[Blair]

Samsung LN40+OSSC line 5x with help from a VP50(non pro) scanlines: 100%

[Monogamous]

1) It has very limited video LPF support, and thus is only suitable for either 1080p input (the or very clean video signals. In other words, it's not suitable for handling any random console out there.
2) It does not support 75ohm sync, which is what you should be getting from most consoles by the end of their SCART cable and what you'll get from the gscartsw-lite

According to Marqs, in reply to my actual original question, 75ohm CSYNC will work depending on the driving circuit. Unless I misunderstood, he noted that if it's originating from a typical 3.3V/5V IC package, it ought to work fine.

My thinking was that low-pass filtering might not be a huge necessity, as I'm planning to use proper minicoax cables for all connections, and am modifying all my consoles for the cleanest possible video output. I was a little worried about it, but I thought I'd experiment.

3) It does not properly support 480i resolution when using separate H/V sync, currently a partial workaround is in place

I didn't know that.

Reading the JunkerHQ Wiki, the AV3 input seems to have trouble recognizing off-spec interlaced signals, which could very well be a problem.

So I suppose you're right, though I might experiment a bit with VGA mods for the PS2. I do like the idea of having a dedicated input for that system.

[borti4938]

According to Marqs, in reply to my actual original question, 75ohm CSYNC will work depending on the driving circuit. Unless I misunderstood, he noted that if it's originating from a typical 3.3V/5V IC package, it ought to work fine.

You missunderstood it. If the 75ohm driven output is designed to be standard sync, you'll have 2x300mV negative peak-to-peak (2x because the 75ohm termination is missing). (LV)TTL sync is a negative sync pulse from (3.3V or) 5V downto 0V.
This has nothing to do with the Vcc of the driving IC in the first place.

My thinking was that low-pass filtering might not be a huge necessity, as I'm planning to use proper minicoax cables for all connections, and am modifying all my consoles for the cleanest possible video output. I was a little worried about it, but I thought I'd experiment.

You need a low pass filter to avoid aliasing effects due to the sampling process. So either your source outputs a appropriately band limited signal or your filter has to band limited your signal for the ADC. Once you have aliasing you cannot removed it with signal processing anymore.
In the second place the filter is ment to reduce noise.

[Monogamous]

According to Marqs, in reply to my actual original question, 75ohm CSYNC will work depending on the driving circuit. Unless I misunderstood, he noted that if it's originating from a typical 3.3V/5V IC package, it ought to work fine.

You missunderstood it. If the 75ohm driven output is designed to be standard sync, you'll have 2x300mV negative peak-to-peak (2x because the 75ohm termination is missing). (LV)TTL sync is a negative sync pulse from (3.3V or) 5V downto 0V.
This has nothing to do with the Vcc of the driving IC in the first place.

I was thinking your average IC package would usually output TTL-level sync for the sake of working well with other components, but I guess that's kind of a dangerous assumption to make.

You need a low pass filter to avoid aliasing effects due to the sampling process. So either your source outputs a appropriately band limited signal or your filter has to band limited your signal for the ADC. Once you have aliasing you cannot removed it with signal processing anymore.
In the second place the filter is ment to reduce noise.

So, basically, getting pixel-perfect digitization without it would be damn near impossible?

[marqs]

Reading the JunkerHQ Wiki, the AV3 input seems to have trouble recognizing off-spec interlaced signals, which could very well be a problem.

If leading edges of source hsync and vsync are aligned then 480i/576i via AV3 should work fine. If they are a bit off then it's possible to improve tolerance by using "AV3 interlacefix"-option or by exchanging R12 (330ohm) with a 220ohm resistor (implemented by default on v1.6 boards).

So, basically, getting pixel-perfect digitization without it would be damn near impossible?

It depends a lot on the source. I'm getting flawless signal from PC and there's not much to complain about DC VGA either.

[Blair]

Some HDMI captures. (https://imgur.com/a/hPCvK)

Line 5x no scanlines

Spoiler

Line 5x scanlines: 100%

Spoiler

Line 5x DVDO VP50

Spoiler

Line 5x Direct

Spoiler

Some digtal camera shots https://imgur.com/a/IAiws

Line 5x

Spoiler

Line 5x scanlines: 100% (with cutaway to see LCD panel closeup, looks cool)

Spoiler

Line 5x no scanlines

Spoiler

[Chocograph]

I got my chance and ordered my unit.

"There is enough for everyone on the list at the moment, once 48 hours
have passed, orders will be opened up to everyone on the newsletter list
(including people who have ordered before) and then open to the general
public."

[Blair]

I got my chance and ordered my unit.

Sweet!

Samsung LN40+OSSC line 4x after FW update

So I was able to find a Firmware update for the Samsung LN40 and it now works with the OSSC line 4x mode directly, unfortunately it's not very impressive. its kinda blurry and has some ringing. its likely down to this TV's mediocre processing. but it's playable (looks better with scanlines at 50%). still no luck with line 5x on this TV, so I would still use an external processor as the LN40 does its best work at 1080p60)

images (https://imgur.com/a/P5fbh)

[Keade]

Is this device worth it for me if the only "old" consoles I have for now are Saturn, Gamecube, Playstation 2 and Wii ?
I understand the 480i support is kinda "raw" (simple line doubling), however the price difference against the X-RGB series and the fact it is also more open and regularly updated look like good selling points.

edit : PAL Gamecube (=> no component ) and PAL PS2 (but most PS2 games support PAL 60, and I have a few NTSC games too (I use SwapMagic).
This is for use with display devices that cannot deinterlace (I have both a 27" 16/9 TN computer monitor, and a good ol' 21" 4/3 CRT monitor), I don't have any actual TV at all, which is why I have been keeping an eye on XRGB / OSSC for a long time
I do like emulators, but would rather rely on the original hardware when emulation is not perfect (which is common, and imho applies to all consoles I have listed).

[Chocograph]

Is this device worth it for me if the only "old" consoles I have for now are Saturn, Gamecube, Playstation 2 and Wii ?
I understand the 480i support is kinda "raw" (simple line doubling), however the price difference against the X-RGB series and the fact it is also more open and regularly updated look like good selling points.

I just like to have options. I play emulators most of the time even though I own a ton of retro stuff and the framemeister. I'm getting this for its ease of use and clean video signal but these days I tend to just flip on my Vita with Retroarch. GC, PS2 and Wii can be emulated so it depends on how much you really want to play those platforms on original hardware. I haven't tried CEMU yet but from what I've seen -at this time- my own opinion is it's not worth it. I need stable 60fps and I don't play emulators that don't give me a rock solid framerate. GBA on retroarch Vita is one example. I'm picky about that. The Dolphin emu for GC and Wii is very good. I can't give any other advice than to look at OSSC videos on youtube. I don't think this was of much help. I don't know much about Sega Saturn emulation.

[Blair]

Is this device worth it for me if the only "old" consoles I have for now are Saturn, Gamecube, Playstation 2 and Wii ?
I understand the 480i support is kinda "raw" (simple line doubling), however the price difference against the X-RGB series and the fact it is also more open and regularly updated look like good selling points.

well, the Saturn is mostly a 240p gaming machine so you won't be using 480i with that outside of a few titles like virtua fighter 2, when it comes to Gamecube do you have the Component/Terminal cable, or do you hook it up via RGB? (OSSC can't use s-video) as far as I know the cube can output 240p but i've only ever seen it done via retroarch or the awesome gameboy advanced player homebrew. but the vast majority of Gamecube native titles support 480p or can be forced into 480p (with swiss) and thats the best way to enjoy GC games.

Playstation 2 can play both ps1 and ps2 games and if you play a good amount of ps1 titles (or want to start) then the OSSC is great for that. as most ps1 games are 240p with some being 240p/480i and very few being 480i only. it's true that most native ps2 titles are 480i (with a few 480p games) if your display or processor does a good job of deinterlacing 480i just use the OSSC's 480i passthru function (that will also work with all other systems outputting 480i like ps1 or even saturn games) the OSSC also has an interlaced (moving) scanline filter setting so you can get that interlaced 480i analog look on digital displays, some users say thats the best way to play those types of 480i optimized games.

I use the Wii all the time with OSSC as it outputs 240p and 480p and the few 480i only titles on Wii can be forced into 480p (with homebrew) and the OSSC can add scanlines to 480p content and that works great with pixel art style games made in 480p (also give the 480p line x2 option a try on 480p titles and see if you like the way it makes games look) Wii U also benefits from the OSSC as it can rectify the notorious RGB full range issue on that system (by using the component out into the OSSC you get a full range HDMI/RGB digital out for the Wii U). lots of great stuff. it all depends on you and how you like to play your games and what diplay you are going to use it on. (not all features are guaranteed to work on every TV or monitor).

Really happy with the results. I have found very usefull the pics of Blair and setings from his vp50.
Thanks a lot !

Awsome! I'm happy my pictures helped you.

Cool video. I liked your mundane soundtrack

Thanks! (i'll have to upload more videos in the future)


Dreamcast, DTV sampling

[ZellSF]

When I said OSSC+DVDO VP50 (framerate unlocked) 480iX2+240pX2 transitions were pretty seamless here's how it looks:
https://www.youtube.com/watch?v=yDguYiX03vU
Obviously it looks sort of bad (the video quality, not the transition smoothness), but for the games people say are broken by 240p>480i menu transitions this is a very good solution. The bobbing doesn't come across well in the capture, just imagine it.

And while I have my capture card connected, I wondered a bit earlier if 480pX2 could help with XRGB-mini's handling of 480p for 2D pixel games:

PSP3000 + OSSC + XRGB-mini in VIDEO mode
PSP3000 + OSSC + XRGB-mini in GAME mode
PSP3000 + OSSC 480pX2 + XRGB-mini in GAME mode

Yeah that's definitely the sharpest PSP output I've seen with the equipment I have available. Not as sharp as emulators though, my Youtube captures of that game (in PPSSPP) are sharper even despite heavy video compression.

Is this device worth it for me if the only "old" consoles I have for now are Saturn, Gamecube, Playstation 2 and Wii ?
I understand the 480i support is kinda "raw" (simple line doubling), however the price difference against the X-RGB series and the fact it is also more open and regularly updated look like good selling points.

Gamecube and Wii: With the OSSC you only gain 480pX2 support and only if your display supports it. Plus for high resolution 3D games, I think a lot of people will prefer not using 480pX2 anyway. Not really worth it, a cheap transcoder would be better for these consoles.

PlayStation 2: Here it gets a bit interesting, because while 480iX2 looks sort of bad, if your TV has a lot of input lag when deinterlacing the tradeoff can be worth it when playing fast reaction based games. 480iX3 and X4 has the same problem as above: I think you'll in the end find out line multiplication doesn't look good for relatively high resolution sources.

Leaving the Saturn as the only console that really benefits, how much it does is entirely dependent on your TV Does it handle 240p from the Saturn as is? Will it handle the higher line multiplication modes from the OSSC?

Wii U also benefits from the OSSC as it can rectify the notorious RGB full range issue on that system (by using the component out into the OSSC you get a full range HDMI/RGB digital out for the Wii U).

The Wii U color range issue is only relevant to very very few displays.

[Chocograph]

What's the Wii U color range issue? That it won't show the wider range even though you set it to full? Are the colors wrong? It seems to be working on my Sony Bravia from 2008. Color range deepens when I enable it. Darker shadows...