OSSC won't sync with Taito Arkanoid 2 JAMMA arcade pcb :(

[jimbodeanny]

In the last month, I received my OSSC and have been really enjoying it! I bought it to be used as a means to capture/record/stream directly from all of my arcade cabinets. I use the Splitfire JAMMA splitter (https://www.arcade-projects.com/forums/index.php?thread/7200-nac-splitfire-jamma-streaming-solution/&pageNo=1) to split the video which gets fed to the OSSC via the VGA/AV3 input, while the other signal still goes to the arcade monitor, allowing me to play on the actual cabinet.

So far, I’ve been super impressed and happy with the results as I’m running line4x into my Elgato capture card with zero issues. I’ve got about 10 arcade cabinets and none of my games have given me any problems with the OSSC, until now. My Arkanoid: Revenge of DOH JAMMA PCB seems to have major problems with the OSSC. It will not sync. All I see on the OSSC LCD is “AV3 RGBS: NO SYNC”

I did some research and found this thread: https://videogameperfection.com/forums/topic/taito-f3-arcade-board-wont-sync-with-ossc-works-with-framemeister/. I figured my issue was similar since Arkanoid: Revenge of DOH is a Taito PCB. Unfortunately, nothing mentioned seemed to fix my issue. I changed the H-PLL pre and post coast to 4, which didn’t help anything. I also played with the Vsync Threshold and while it DID change the status, it would never completely sync (the LCD numbers constantly change/flicker as if it’s trying hard to lock the signal, but the LED stays red and there’s no image displayed.) It’s frustrating to see because it looks like it’s so close!

I’ve turned the PCB off and on while the OSSC is on, and vice versa to no avail.

I’m at a loss here and not sure what to do next. It would be a real bummer if this was the ONLY arcade game that won’t work with the OSSC =\

Any ideas/help would be greatly appreciated!

Thanks!!

-Jim

P.S. Sorry, I don’t own an oscilloscope 😉

[jimbodeanny]

I forgot to mention that I’m running the latest firmware (0.82)

[marqs]

If possible, try AV1 (SCART) input as well since it has slightly different sync processing.

[jimbodeanny]

Thanks for the reply marqs!

So I have good news and bad news…

The good news is that using AV1 worked! I have one of the JAMMA/scart adapters so I plugged that into my cabinet and I was able to get an image once I cranked up the vsync threshold! So that was great to see.

The bad news is that I seem to be getting some stuttering/dropped frames.

Here is a video I recorded through OBS. https://youtu.be/eLY1hhYI7Gk

It’s most noticeable during the scrolling text beginning at 0:12, again at 1:21 and again at 2:03. I’m not sure how to correct this. I’ve tried all of the different line modes (2x,3x,4x,5x) and it doesn’t seem to make a difference.

Ideas…thoughts?

Quick note: This is a vertical game so the video is rotated 90 degrees. Just FYI.

Also, any recommendations on a VGA to SCART cable/converter? I eventually want to be using my Splitfire again which outputs via VGA, so I need to convert that to SCART so I can use AV1

Thanks!!

-Jim

[megari]

Are you sure the stuttering is not caused by your capture/display device? The OSSC does not change the timing of the video output – it is physically incapable of this due to the lack of a frame buffer.

Looking at the Youtube video, it looks more like shimmer. Is the input video interlaced, by any chance? Deinterlacing could cause shimmering artifacts.

[jimbodeanny]

It’s not being caused by my device(s), it happens the exact same way on both my capture card and TV. This issue doesn’t happen with any of my other arcade games that are connected on AV3 via VGA. It only happens with this game that’s running through AV1/SCART.

The input video is straight RGBS from the JAMMA PCB. Again, I’ve had no issues like this with other arcade PCBs, including JAMMA. It only happens with this game, but again…this is the only game that I have connected via AV1 since it doesn’t work with AV3.

It doesn’t look like a “shimmer” to me, but more like a frame is dropped as the scrolling text seems to jump every so often. If it is an issue from interlacing/deinterlacing, how would I fix it? On that note, how would I find out if it is an interlaced signal? The OSSC is running it in 240p and I typically use Line4x or 5x.

[nmalinoski]

On that note, how would I find out if it is an interlaced signal? The OSSC is running it in 240p and I typically use Line4x or 5x.

The OSSC LCD will tell you what kind of signal it’s receiving. Specifically, the i or p immediately following the line count will tell you whether it’s receiving an interlaced or progressive signal respectively.

[jimbodeanny]

The OSSC LCD will tell you what kind of signal it’s receiving. Specifically, the i or p immediately following the line count will tell you whether it’s receiving an interlaced or progressive signal respectively.

Got it, thanks! I’ll have to check that when I get home.

[Harrumph]

Also, if the framerate of the board is very far from standard 50hz/60hz, stuttering may be caused by framerate conversion performed by your card/TV. Try setting your capture to the exact framerate the OSSC reports.
Otherwise, I wouldn’t rule out it’s still some type of sync issue.

[jimbodeanny]

Thanks for the responses!

The OSSC LCD will tell you what kind of signal it’s receiving. Specifically, the i or p immediately following the line count will tell you whether it’s receiving an interlaced or progressive signal respectively.

Ok, I just checked the input signal and it’s 264p so that rules out the interlace theory I think.

Also, if the framerate of the board is very far from standard 50hz/60hz, stuttering may be caused by framerate conversion performed by your card/TV. Try setting your capture to the exact framerate the OSSC reports.
Otherwise, I wouldn’t rule out it’s still some type of sync issue.

It’s a standard 60hz signal. The OSSC reads it at 59.18Hz.

[nmalinoski]

264p and/or 59.18Hz may be just enough out of spec that your HDMI hardware is rejecting the linedoubled output.

NTSC is typically 525 lines at 59.94 or 60Hz; 240p is usually 262 or 263 lines, making the line-doubled output 524 or 526 lines, which most displays will tolerate. So, 528 lines might be just one too many for your hardware to tolerate. Separately, or in combination with the line counts, the vertical refresh rate might be a little too low.

What line counts/refresh rates have you experienced with your other PCBs? Are they all pretty close to typical 240p or 480i at 59.94 or 60Hz, or are there some that work that are as off-spec as or worse than this PCB?

[jimbodeanny]

Okay, so I tested out a few other sources that haven’t given me issues.

My Toki pcb is detected as 259p, 60.32Hz. It’s the same whether I connect it via AV1 or AV3

My arcade test pattern generator is detected at 262p, 60.33Hz. This is connected via AV3.

My Ms. Pacman pcb is detected at 264p, 60.55Hz. This is connected via AV3.

Since Ms Pacman is also detected at 264p, I’m wondering if maybe it’s the frequency? If I plug my Arkanoid: Revenge of DOH pcb into AV3, it never completely sync, but I see the numbers rapidly change, ranging from roughly 259p – 265p.

I don’t know what this all means.

I’m not sure where to go from here. Any thoughts or help are appreciated!

[jimbodeanny]

When I open the same games up in MAME, it lists these resolutions…

Arkanoid: Revenge of DOH
256×224 60.000000Hz

Toki
256×240 60.000000Hz

Ms. Pac-man
288×224 60.606060Hz

Not sure if that helps or means anything.

[Harrumph]

It’s a standard 60hz signal. The OSSC reads it at 59.18Hz.

That’s not a standard signal. ;-P
It deviates from standard by 0.8 Hz, more than any of your other boards. I’m now pretty sure it’s the refresh that exceeds the tolerance of your card and TV, causing them to apply frame conversion.

As I wrote earlier, try to match capture framerate with that of the board. For your TV, you will have to live with it or get another display. It’s also totally possible that the framerate tolerance of your sinks is different for different resolutions, so you should try all multiplication modes and see if it helps.

[jimbodeanny]

That’s not a standard signal. ;-P
It deviates from standard by 0.8 Hz, more than any of your other boards. I’m now pretty sure it’s the refresh that exceeds the tolerance of your card and TV, causing them to apply frame conversion.

As I wrote earlier, try to match capture framerate with that of the board. For your TV, you will have to live with it or get another display. It’s also totally possible that the framerate tolerance of your sinks is different for different resolutions, so you should try all multiplication modes and see if it helps.

DOH. I didn’t realize that, but it makes sense.

I’ve been capturing at 60fps. I’ve tried all of the different multiplication modes with the same results.

I don’t care about my TV display as I’m not aiming to play these games on an HD display. The capture quality is all I’m concerned with as I’m only going to be using the OSSC to capture/record/stream while playing on my original arcade cabinets. I don’t mind spending some money to achieve that. On that note, I’m wondering if I’m going to need some other piece of hardware? Would the Framemeister be the better choice and/or work better in tandem with the OSSC? My main goal is to be able to record/capture a direct feed from my multiple arcade cabinets. Some are JAMMA games, many are old classic (i.e. Pac-man). This has been quite the rabbit hole of a project!

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