RGB 2600 with RetroTINK 5X - screen tear issue

[Jetboot Jack]

I wonder if anyone has a PAL 2600 fitted with a Tim Worthington Atari 2600 RGB KIT and is running it thru an upscaler to HDMI?

 

I have this setup and am using a RetroTINK 5X to get the 2600 onto my OLED TV and I see a screen tear/jitter in the output (5X has the latest firmware) - PAL 50/60/NTSC games all show the same issue - a small constant tear across the whole screen for about 10-15 lines, vertical position varies by cart used it appears on all games to some degree.

 

sTeVE

[Jetboot Jack]

Well - I have kinda solved my issues - I bought a OSSC, seems that likes the output far more than the RetroTINK, which is very odd as in my experience the RT works so well with so many systems.

 

sTeVE

[+-^CrossBow^-]

10 minutes ago, Jetboot Jack said:

Well - I have kinda solved my issues - I bought a OSSC, seems that likes the output far more than the RetroTINK, which is very odd as in my experience the RT works so well with so many systems.

 

sTeVE

This is strange as I thought one of the issues the OSSC has is that it isn't nearly as tolerant of the games that don't follow proper sync rules whereas the Tink5x has corrected for some of that with the triple buffer mode? Then again, that is mostly an issue with NTSC games too isn't it?

 

[Jetboot Jack]

NTSC, PAL 60, PAL all work just fine with the OSSC, but have the jitter/tear on the TINK - which 100% surprised me too.

 

Now it could be a quirk with my RGB install, or the 2600 it's fitted to that means it has an output with some variance that the TINK dislikes. It could be a bad TINK - but it works fine with my other gear (CVBS and SVIDEO) - perhaps it's just on the Scart?

 

End of the day this setup seems to work just fine for me now 🙂

 

sTeVE

 

 

[+MrZarniwoop]

On 1/5/2023 at 9:02 AM, Jetboot Jack said:

I wonder if anyone has a PAL 2600 fitted with a Tim Worthington Atari 2600 RGB KIT and is running it thru an upscaler to HDMI?

I have a couple of 2600RGB consoles, both work fine with the RetroTINK-5X Pro with no tearing. They are, however, both NTSC consoles. From the documentation, it makes it sound when the 2600RGB board is the output, it behaves the same on PAL/NTSC games just auto-selects different color palettes. I can share my primary settings if helpful? I did change a bunch of settings that worked better for me.

 

Overall, the RT 5X worked better for me than with a 2600RGB than a Framemeister xRGB or OSSC, for the dynamic scan line sync reasons @-^CrossBow^- noted. But, the 5X-scaled OSSC picture on a 2600RGB is pretty damn amazing. It was only when the RT 5X added HDR injection support that it beat the OSSC video quality on the 2600RGB from my eyes.

[Jetboot Jack]

On 1/9/2023 at 10:18 PM, MrZarniwoop said:

I can share my primary settings if helpful? I did change a bunch of settings that worked better for me.

That would be fantastic - yes please!

 

sTeVE

[+MrZarniwoop]

I'm away from my RetroTINK 5X-Pro for the next four weeks, so I can't get to all the settings. I know I have the latest 3.0 firmware, and use the Generic 4:3 sampling mode. but I also had these written down as my RT 5X-Pro settings with a 2600RGB:

 

Input Source: SCART-RGB

Output Resolution: 1200p (using LG C7 OLED TV)

V Position: -9 (29)

V Size: +5% (1720)

H Crop Start: 206

H Crop End: 1832

SDTV LPF: Off

LLPLL Gain: 1

 

I know I also have HDR injection and one of the post-processing scanline masks turned on, I don't remember which one.

 

 

[+MrZarniwoop]

I will just add some general settings advice from Mike Chi if you have a source that doesn't sync correctly with screen tearing, waviness, or curl issues when using the RetroTINK-5X Pro. Unfortunately, there is no formula, it's a "these are settings you have to play with" situation. You're trying to stabilize the pixel clock, a very important element in providing the clearest and most stable image when capturing analog RGB signals from the 2600RGB and digitizing them for the RT 5X HDMI output. 

 

1. Go to the Video ADC (video decoder analog-to-digital converter) settings menu, largely around configuring the ADC/LLPLL (line-locked phase-locked loop) system that generates the pixel clock

2. Turn LLPLL Gain (PLL loop gain control) down to 1 decreasing brightness and increasing contrast by decreasing video signal power/amplitude

3. Lower the LLPLL BW (PLL filter bandwidth control) down to 3 or 4 to provide a better quality signal over a wider range of conditions, although normally with perfectly matched impedances the best performance would be obtained with the widest possible signal bandwidth

4. Move the SoG Thresh (sync-on-green slicer threshold control) up and down from default 120 mV to set the sync trigger level above the negative peak of the input signal

 

That fixes some bad sources, but it's a process of trial and error.

 

Other things to try changing depending on the video source:

 

- SDTV LPF (low-pass filter) for 240p/480i (NTSC) or 288p/576i (PAL or SECAM) sources like the 2600RGB can sometimes help to reduce high-frequency noise, optimizing transient color performance, but sometimes with trade-offs: off or light won't really impact sharpness, but medium or strong causes some "ringing effect" that can create a border between sharp color transitions due to curvature of analog signal

- EDTV LPF doesn't impact the 2600RGB, as it's for 480p (NTSC) or 576p (PAL or SECAM) sources that can output progressive scan; noted just in case you're doing something unusual like using a line-doubler between the 2600RGB and RT 5X

- Pre-Coast (number of HSYNC periods that coast is active before VSYNC edge)

- Post-Coast (number of HSYNC periods that coast is active after VSYNC edge) <- this helped me with a ColecoVision modified with RGB video output

- ADC Phase of the generated sampling clock may be shifted to locate an optimum sampling point in degrees, default 180.00 Deg, within a clock cycle (sampling phase on pixel 00 time)

[+MrZarniwoop]

Just more info about using coast to sync video from an RGB ADC manual, usually to fix screen tearing:

Quote

In some systems, however, Hsync is disturbed during the Vertical Sync period (Vsync). In some cases, Hsync pulses disappear. In other systems, such as those that employ Composite Sync (Csync) signals or embedded Sync-on-Green (SOG), Hsync includes equalization pulses or other distortions during Vsync. To avoid upsetting the clock generator during Vsync, it is important to ignore these distortions. If the pixel clock PLL sees extraneous pulses, it will attempt to lock to this new frequency, and will have changed frequency by the end of the Vsync period. It will then take a few lines of correct Hsync timing to recover at the beginning of a new frame, resulting in a “tearing” of the image at the top of the display.

 

[...] COAST [generated from Vsync input or the output from the sync separator] is provided to eliminate this problem. It is an asynchronous input that disables the PLL input and allows the clock to free-run at its then-current frequency. The PLL can free-run for several lines without significant frequency drift.

[Jetboot Jack]

Wow - thanks for all the extra information, now I just need some quiet time to play with the settings and see what corrects the issues I experienced.

 

And as a repository of TINK info this is great!

 

sTeVE

[+MrZarniwoop]

I would think turning down the LLPLL Gain to 1 may be all you need if your situation is similar to mine, but it's always best to understand the settings you're playing with! The settings I noted earlier are from an Atari 2800 (Japanese model) with 2600RGB that @-^CrossBow^- installed.

 

The only other advice is to try some "tall" games to set your V Position/V Size settings for your screen size, as Atari 2600 games can use a variable number of lines. I use the top orange pixels of the Harmony Encore cartridge menu screen to set the top of the screen as it displays those up pretty high, usually higher than games, and then use Star Wars: Empire Strikes Back to set the bottom as it's a very clear colored section. I set my RT 5X profile so both carts display right to the top or bottom edge of the display. If you sometimes play PAL games that are "taller" with more scanlines, you can can either have a 2600 NTSC and a 2600 PAL profile, but a benefit of the 2600RGB is you could use just one unified 2600 profile and use the PAL version of SW: ESB to set the bottom of the screen knowing NTSC games won't fill the screen.

 

The Triple Buffer sync mode mentioned earlier is good at maintaining video output stability by buffering frames with RT 5X-generated clock compensating for weird sync issues with variable scanlines/HSYNC or odd or variable VSYNC timing while the game is running, but I would not expect it to help with screen "tearing" or video noise. Assuming good cables, I'd start with the Video ADC settings explained above. It's worth noting also that most games work fine in Frame Lock (2600RGB-clocked unbuffered sync) or Gen Lock (RT 5X-generated clock from 2600RGB that isn't locked to 2600RGB frame rate unbuffered sync) sync modes if you're looking for the minimum lag possible, best for twitchy games like Kaboom.

[Jetboot Jack]

So I have an RGB 2600 jnr now hooked up via a RetroTink5 - and I took all your recommendations @MrZarniwoop and I have a 98% perfect setup!

 

Which is a huge improvement - so massive thanks for the pointers.

 

Now I just have to figure out the "tiny" little judder I get about 1/3 down the screen - a little sideways shudder on about 6 scanlines.

 

To be honest you NEVER notice it while playing, but it can be seen if you let the screen display just sit there and you look for it.

 

sTeVE

 

 

[Jetboot Jack]

I keep flip flopping between triple buffer and genlock modes on the HDMI output, I *think* Genlock is best 🙂

 

Oh and one weirdness - I cannot get Spy Hunter to display (NTSC version) - I get a torn display then the Think goes into no signal mode and I can hear the sound, but no display is visible 😛

 

sTeVE

[+MrZarniwoop]

4 hours ago, Jetboot Jack said:

Now I just have to figure out the "tiny" little judder I get about 1/3 down the screen - a little sideways shudder on about 6 scanlines.

I get something similar playing 2600 games on my v1 7800GD.