OSSC Pro

[Zacabeb]

Downscaling with dedicated scaling algorithms for the purpose (requiring a kernel with more taps) could provide better scaling without moiré as well as baked-in flicker reduction. A convolution kernel after the scaling step could perform flicker reduction also when using integer scaling (2 taps for basic flicker reduction, 4 to 7 taps for higher quality and/or more aggressive flicker reduction.)

[fernan1234]

Yep. Downscaling and transcoding is the only reason why I got an OSSC Pro (+AV input/output adapters). But even at that it is currently outperformed by a Tink4K+DAC. Obviously the OSSC Pro cannot be the best at upscaling, but feels like it has the potential to be the best in class for downscaling/transcoding, so it'd be a good focus for it.

[marqs]

Ah, I see. I hope IVTC gets added and maintained at some point in an alternate firmware despite it being a somewhat niche feature.

I made a test image for it which will be available soon with the release of next standard firmware. Actually the resources usage was lower than I remembered but it severely degraded deinterlacer performance and thus cannot be used for 1080i.

Also, for component input (specifically YPbPr) I've been noticing a strange issue where 240p content (tested with my PS2 running PS1 games, GameCube, Wii, and modded N64) won't work at all using 4x or 5x line multiplier to 1080p and has a strange flickering line near the bottom of the screen when using 720p. These issues are not present on any of the RGB inputs from the same sources.

Sounds like there might be issue with the HW, but it's worth checking out with another monitor.

In addition, sometimes the HDMI input will glitch out on a resolution change from my GameCube/Wii (which requires me to reboot the OSSC Pro), and 480i occasionally doesn't show up well (looks like it may sometimes interpret even as odd and vice versa. Switching the input to a different source and back sometimes fixes the issue).

Do these occur in A-LM or Scaler mode, or both? There is a known A-LM issue of screen freeze and another Scaler issue of ghosting. but both occur very seldomly (thus hard to debug!) and are unrelated to interlace.

[LDigital]

Yep. Downscaling and transcoding is the only reason why I got an OSSC Pro (+AV input/output adapters). But even at that it is currently outperformed by a Tink4K+DAC. Obviously the OSSC Pro cannot be the best at upscaling, but feels like it has the potential to be the best in class for downscaling/transcoding, so it'd be a good focus for it.

Hold on… what is this? Last I heard tink4k wasn’t great for downscaling. I have an analogue dac for my nt. are you saying that this combo is now better? I’m unsure how line decimated 720p could be beaten tbh as its lag free and sharp as a tack on my bvm

[orange808]

The analog output option is fantastic. In my opinion, the value of the OSSC Pro's optional "built in" DAC (analog output) can't be understated.

[e8root]

Yep. Downscaling and transcoding is the only reason why I got an OSSC Pro (+AV input/output adapters). But even at that it is currently outperformed by a Tink4K+DAC. Obviously the OSSC Pro cannot be the best at upscaling, but feels like it has the potential to be the best in class for downscaling/transcoding, so it'd be a good focus for it.

How is RT4K outperforming OSSC Pro in downscaling if all materials about these devices point downscaling on RT4K being a much less supported feature with more lag and otherwise lacking line blending?

edit://
Silly me, I jumped to downscaling but your post was about transcoding also.

In downscaling OSSC Pro seems to be currently the best option. Not perfect or anything and I see lots of room for improvement and maybe in some specific cases RT4K might be better but as a whole even ignoring price difference OSSC Pro seems like a better downscaler.

[GK6475]

Great, I'd love to give IVTC a try with some 480i content. I would find it useful primarily for 480i and similar input resolutions anyhow given how well 1080i is processed by the vast majority of my displays.

I see the line flicker issue on my Panasonic plasma GT30 TV, which doesn't have issues with 720p and 1080p signals normally, even when using A-LM mode for RGB signals. The flickering line happens exclusively with YPbPr input for the same signals with the same timings going in. Maybe it is a hardware problem, though I wouldn't know what exactly is responsible for it. I can do some soldering, so assuming it isn't a near-microscopic chip that a simple soldering iron can't get to, I could probably replace whatever is causing issues.

The screen freeze seems more related to A-LM mode, I haven't seen these issues occur in scaler so far. I've noticed it happening more with the latest firmware, but I also recently disabled "fix resolution" on the GCVideo device right after updating. I'd like to enable "fix resolution" but the 720px input makes 640px and lower content look squished on some output resolutions and doesn't scale down well (doesn't crop) to a custom 640x480 output (which I use on my CRT monitor that can't fully crop black bars from a 720px signal).

[marqs]

The 0.80 firmware has been now released and is available from github.

The version with cadence support can be downloaded here. To keep things simple at this point, scaler pipeline frequency is halved and thus 1080p60 or equivalent bandwidth is maximum attainable. Cadence settings are found under Scaler opt.

[LDigital]

The 0.80 firmware has been now released and is available from github.

The version with cadence support can be downloaded here. To keep things simple at this point, scaler pipeline frequency is halved and thus 1080p60 or equivalent bandwidth is maximum attainable. Cadence settings are found under Scaler opt.

I must have missed the chat on this. What is cadence support?

[Zacabeb]

The 0.80 firmware has been now released and is available from github.

The version with cadence support can be downloaded here. To keep things simple at this point, scaler pipeline frequency is halved and thus 1080p60 or equivalent bandwidth is maximum attainable. Cadence settings are found under Scaler opt.

I must have missed the chat on this. What is cadence support?

Cadence is the pacing of actual frames within a picture signal. In the case of a 24 fps source inside a 60 Hz signal, every other frame is repeated twice and every other frame thrice, called 3:2 pulldown. Not only does that cause irregular cadence, but it also makes an interlaced signal a bit harder to de-interlace well. Inverse telecine or IVTC for short allows this to be detected so that the de-interlacing is forced into weave mode while taking the irregular cadence into account. It can also be used (I don't know if it's the case with the OSSC Pro) to switch to a 24 Hz output, fixing the irregular cadence as well.

It requires more sophisticated analysis of the motion between frames to establish the cadence than the basic motion adaptive de-interlacing provides, hence the overhead and need for a separate firmware fork.

[orange808]

There's a good reason to detect cadence and handle tecline interlacing properly.

We can recover the full frame. The fields of NTSC or PAL interlaced video hold all the information from the original~24fps source material. It's good to recover the entire frames. No guessing required.

[LDigital]

Thanks. All makes sense. Interesting to learn how that is done

[2mg]

Anyone got a TLDR of Koryuu vs Legacy AV board, except for price difference?

Or skip both, get RT-mini/2X for Composite/S-video sources and then HDMI out > OSSC Pro?

[Zacabeb]

Anyone got a TLDR of Koryuu vs Legacy AV board, except for price difference?

Or skip both, get RT-mini/2X for Composite/S-video sources and then HDMI out > OSSC Pro?

The Legacy AV In, Koryuu Transcoder, and RetroTINK 2x MINI (as far as I know) are all based on the Analog Devices ADV7180/ADV7280 analog front end ICs, so their comb filtering behavior is fundamentally the same.

The advantage of the Legacy AV In is that you get the adaptive de-interlacing of the OSSC Pro which you don't with the 2x MINI, no additional conversion to analog and back to digital like you do with the Koryuu, and extensive control over the decoder settings. The only downside for now is that there is no simple toggle yet in the Legacy AV In settings between comb and notch filtering for composite video, so if you want to disable comb filtering you have to set up suitable notch filter settings manually. The upside is that you can optimize them for the console.

So, the Legacy AV In is in my opinion the best option overall for composite or S-video input to the OSSC Pro. I'd recommend the 2x MINI or Koryuu only if you need to use the expansion port for something else.

[GK6475]

The 0.80 firmware has been now released and is available from github.

The version with cadence support can be downloaded here. To keep things simple at this point, scaler pipeline frequency is halved and thus 1080p60 or equivalent bandwidth is maximum attainable. Cadence settings are found under Scaler opt.

IVTC/cadence works amazingly, thanks a lot for adding that! However, I still have the issue where YPbPr optimized timings don't work very well with each device (modded N64, stock PS2) I've tested. RGsB shows a green but proper picture, but when I switch to YPbPr and switch to an optimized mode (N64 320px and even N64 640px for example), my displays report no signal (for 1080p A-LM and scaler mode, 720p still has the strange flickering near the bottom of the screen). Interestingly, some of the modes for the other consoles and generic 4:3 still work when using YPbPr with these consoles. Over RGB, these devices perform as they should and their modes work well with them and on all of my displays. In scaler mode, turning off framelock seems to make respective optimized modes work with YPbPr at the cost of higher latency and not as good of frame pacing. I'm considering just building or buying a YPbPr to RGB transcoder to solve this issue, since part of my setup is integrated using YPbPr, but it'd be great if this is something that can be fixed in software or the OSSC Pro's hardware. These issues are noticeable on my Panasonic GT30 plasma, my capture card (Avermedia Live Gamer HD) and my Samsung LC32G75TQSNXZA as well as every other display that I've tried it on.

[marqs]

I managed to rteproduce the issue with PSX/N64 optimized presets on YPbPr. Somehow clamping mode selection on the video ADC seems to affect sync extraction/timing even though it should be identical to RGsB mode. More investigation is needed to see if there is anything that can be done or if it remains mystery like the HV sync issue with a few sources like X68k (later boards were equipped with a HW workaround for it, though).

[2mg]

The Legacy AV In, Koryuu Transcoder, and RetroTINK 2x MINI (as far as I know) are all based on the Analog Devices ADV7180/ADV7280 analog front end ICs, so their comb filtering behavior is fundamentally the same.

The advantage of the Legacy AV In is that you get the adaptive de-interlacing of the OSSC Pro which you don't with the 2x MINI, no additional conversion to analog and back to digital like you do with the Koryuu, and extensive control over the decoder settings. The only downside for now is that there is no simple toggle yet in the Legacy AV In settings between comb and notch filtering for composite video, so if you want to disable comb filtering you have to set up suitable notch filter settings manually. The upside is that you can optimize them for the console.

So, the Legacy AV In is in my opinion the best option overall for composite or S-video input to the OSSC Pro. I'd recommend the 2x MINI or Koryuu only if you need to use the expansion port for something else.

Thanks!

Have a couple more questions if you don't mind:

1. Is the RF input for AV board still in progress, as in not abandoned?
1a. If it's still WIP, the current AV boards aren't RF DIY future-proof aka when RF+AV boards come they will have to be re-purchased, current ones can not be modified?

2. It's not possible to have additional VGA output board with AV board simultaneously? Is this subject to change?

3. OSSC Pro has no TBC, correct? But with the right filter for composite, it is relatively VCR friendly (aka what Retrotink has implemented, Retro/Notch filtering)?

4. What's the pro of using Legacy AV compared to using RT2X for AV? More controls in OSSC Pro itself?

5. Slightly off-topic, but was the color issue with Koryuu that was reported quite some time ago fixed?

[BuckoA51]

1) It's not looking great for the RF board no matter what Markus seems to try there's always a ton of interference. I sent a board to a contact who used to be a CRT engineer to see if he could suggest any improvements. The current boards could be modified for RF but then they'd lack any improvements we may be able to engineer into the final design (if there ever is another revision).

2) No you can only have one or the other, I believe there isn't enough IO space for a card that does both at the same time.

3)No TBC but I did test with VHS and RF recently, watched a whole episode of Voyager from an old tape out of the loft and it seemed fine.

4) Yes basically that, more controls, neater integration and needs only one PSU.

5) Koryuu's not had a fw update in quite some time sorry.

[Zacabeb]

1) It's not looking great for the RF board no matter what Markus seems to try there's always a ton of interference. I sent a board to a contact who used to be a CRT engineer to see if he could suggest any improvements. The current boards could be modified for RF but then they'd lack any improvements we may be able to engineer into the final design (if there ever is another revision).

My testing so far with the 1.4 board has suggested that if there is not a ton of interference in the frequency ranges desired (basically channels 3 and 4 in the M/N system and 36 in the G and I systems) and the cable is well shielded, it performs quite well even with a moderately powerful signal. That of course depends on the environment and how much interference there is from other sources. The results varied substantially with the cables I tried and the poor quality cables that came included with legacy consoles are probably a no-go. Crusty RF modulators may also be an issue.

IMO, the RF equipped board needs more testing across different environments and with different sources before considering it a failure.

Addendum: With the signal attenuated and poorly shielded cable running into the adapter, I do get the same interference from the OSSC Pro itself as Marqs has detailed, but with a well shielded cable that specific interference disappears.

[BuckoA51]

Does anyone have a link to a well shielded RF cable? All mine are generic.

I was comparing a VHS player with RF in the same room as the OSSC Pro plus RF card when I did my tests.

[Zacabeb]

Does anyone have a link to a well shielded RF cable? All mine are generic.

I was comparing a VHS player with RF in the same room as the OSSC Pro plus RF card when I did my tests.

The cables I found to work without interference were rated Class A for shielding. I've tested a few new ones with both F-connectors and Belling-Lee (aka IEC or PAL) connectors, the latter through adapters to F. Two other new cables that had no given rating for shielding gave visible interference even with a moderately powerful signal (60 dBµV or so).

There seems to be a pretty common failure among manufacturers of cheaper cables not only in shielding them properly, but also in complying with the dimensions for connectors. F connectors that won't screw on all the way to make proper connection and secure it, Belling-Lee ones that won't stay plugged in. Those standards are over 70 and 100 years old respectively at this point, but still it's hit-and-miss. It's incredibly frustrating.

Edit: One of the things worth testing further is if a relatively short length (1 m/3 ft or so) of well shielded cable can be spliced in between the OSSC Pro and a legacy RF cable, and help reduce interference simply by the legacy cable being moved away from the OSSC Pro.

[marqs]

Edit: One of the things worth testing further is if a relatively short length (1 m/3 ft or so) of well shielded cable can be spliced in between the OSSC Pro and a legacy RF cable, and help reduce interference simply by the legacy cable being moved away from the OSSC Pro.

I finally got some additional equipment and can confirm this. With both double-shielded cables I tried (one unbranded, another Goobay 11830), the interference dropped to almost unnoticeable level. I also tried Hama 00205234 antenna amp and it managed to produce similar result with a bad quality cable which by itself showed highest level of interference even if the junction was 1.5m away from Pro.

[BuckoA51]

Interesting, so Markus you're saying we could maybe bring this to market if we just bundle it with a good quality RF cable? Nice.

[marqs]

Interesting, so Markus you're saying we could maybe bring this to market if we just bundle it with a good quality RF cable? Nice.

For machines with built-in RF modulator using RCA or F-type connector, the following cable (and adapter where applicable) should presumably provide the most robust connection method:
https://www.amazon.de/-/en/Installation ... B09D3ZYSYF
https://www.amazon.de/-/en/Greluma-Adap ... B0D7VDNSSH

[M3Patterns]

That cable looks decent but there are better options. That cable uses aluminum braids which are not as good as copper braids for shielding.

A good broadcast quality Belden or Canare coax cable is most likely going to provide better shielding. For instance, most of Belden's professionally used coax cables have a 95% tinned copper braid, plus a double sandwich of 100% aluminum foil.

Some coax cables are super thick and inflexible, but there is the mini RG-59 size, which is thin and relatively flexible yet can still accommodate the same broadcast quality shielding. For instance, Belden's 1855A or 4855R coax still has a shielding of 95% tinned copper / 2x 100% aluminum foil.

The next size up (regular RG-59) is probably overkill for the short runs we are doing, plus is a relatively inflexible cable. (I have some Belden 1505A cables and they are quite rigid.)

That being said, Belden does make the flexible 1505F cable that swaps the solid copper conductor wire for stranded copper wire, and swaps out the double 100% aluminum foil for another 95% tinned copper braid (which means double 95% tinned copper braid). I'm not sure if the 1505F has enough shielding for what is being experienced on the Legacy AV in, but I think there is a good chance it does.

-----

You can find premade Belden 1855A BNC to BNC cables from several manufacturers. I also saw some premade BNC to RCA cables. Blue Jeans Cable in the US also makes custom sizes and options: https://www.bluejeanscable.com/store/sh ... /1855A.htm .

Ideally you would have someone make you an F-connector to RCA cable. Blue Jeans Cable doesn't have that option in 1855A, but they do have that option in 1505F: https://www.bluejeanscable.com/store/sh ... /1505F.htm .

-----

Another option is to make the final RF Legacy AV In have a BNC connector, rather than an F-Connector, since most premade broadcast quality coax cables are found BNC to BNC. (I understand that that is probably not the easiest option, though.)

[M3Patterns]

After looking into what the actual issue with the RF in is, which marqs said is "EMI caused by OSSC Pro itself which gets coupled to the RF signal in certain degree," I'm not sure if the ultimate culprit is EMI, RFI, or both.

If it's EMI, more copper braid shielding might be better.

If it's RFI, more foil shielding might be better.

This is based on tests that Blue Jeans Cable did here: https://www.bluejeanscable.com/articles ... ection.htm . They found that audio signals were more susceptible to EMI and that 2x (double braided) copper was better in rejecting EMI than a single copper braid with 100% aluminum foil.

That means that if EMI is the culprit, Belden 1505F might be a better option (or Canare LV-77S, although it is less flexible).

If RFI or both are the culprit, Belden 1855A might be a better option.

[WobblingPixels]

Took me a while but it's finally finished

OSSC Pro NTSC & PAL Profiles 2025-11-28 for over 14 systems
Includes CRT profiles. Almost every profile has two sets of settings (Scaler and Linemultiplier Adaptive mode).
For more info and additional optimization check the video tutorial and spreadsheet guide.

1. Update firmware to 0.81 or newer (MUST!):
https://github.com/marqs85/ossc_pro/releases

2. Profiles download:
https://drive.google.com/file/d/1qJSigg ... 117lMtKHhP

3. Video + Installation tutorial:
https://www.youtube.com/watch?v=kJUMBzgd-84

4. Spreadsheet guide:
https://docs.google.com/spreadsheets/d/ ... id=0#gid=0

[XtraSmiley]

Hey Marqs, it's been a long time, is the rotation feature still on the "to do" list and if so, do you have an ETA for it? It's still my must have feature for any scaler!

Thanks!

[Gunstar]

Took me a while but it's finally finished

OSSC Pro NTSC & PAL Profiles 2025-11-28 for over 14 systems
Includes CRT profiles. Almost every profile has two sets of settings (Scaler and Linemultiplier Adaptive mode).
For more info and additional optimization check the video tutorial and spreadsheet guide.

1. Update firmware to 0.81 or newer (MUST!):
https://github.com/marqs85/ossc_pro/releases

2. Profiles download:
https://drive.google.com/file/d/1qJSigg ... 117lMtKHhP

3. Video + Installation tutorial:
https://www.youtube.com/watch?v=kJUMBzgd-84

4. Spreadsheet guide:
https://docs.google.com/spreadsheets/d/ ... id=0#gid=0

That's a ton of work! thank you for sharing+making these.

[BuckoA51]

Took me a while but it's finally finished

OSSC Pro NTSC & PAL Profiles 2025-11-28 for over 14 systems

MUCH appreciated! When I get a moment I'll add a link onto the wiki for this too.